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@andreamerello
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I've changed the adi_axi_hdmi driver in order to work with the new, mainlined, VDMA driver while keeping it backward compatible with the old VDMA driver. Support for both single and interleaved transfer mode has been thus kept.

Unfortunately I needed to patch the mainline VDMA driver becasue it missed DMA_INTERLEAVE in cap_mask (I'll push this patch also to the mainline).

I also realized that since the new VDMA driver do not uses anymore a "overloaded" version of dma_slave_config struct, and it exports it's own function for private configuration, we would run in linking error if the new VMDA driver is not selected in kernel config, so I enforced this in KConfig. I honestly don't like this solution because we still support also the older VDMA driver, but since this should be, I hope, just a transitory situation, I think it might be reasonable (RFC).

Andrea

mhennerich and others added 5 commits November 23, 2015 16:07
This driver was tied to a old-version, not-mainlined, Xilinx VDMA driver.
A custom configuration API was used for passing a bunch of parameters
to the VDMA driver.

By using the interleaved API most of this custom stuff is no longer needed
and this makes also things working with the mainlined version of VDMA driver.

For now the old DMA API is still supported in order to ensure compatibility
with the old VDMA driver, otherwise users who update kernel keeping the old
DT/driver would have things broken. The interleaved mode will be automatically
used when available on the DMA channel.

Note that, AFAICT, this works (and ever worked) only because the Xilinx VDMA
implementation implicitly do cyclic transfers; so that making adi_axi_hdmi to
use the standard DMA API is not enough to state it will work with any dmaengine
driver that supports interleaved transfers. AFAIK this is odd, and there is no
way to ask for cyclic transfers on the top of interleaved transfers (RFC).

Beside that, the new VDMA driver still has a custom-API for configuration,
but this time we need it only to flip a configuration flag.
I suspect we indeed need to flip it only because of a bug in the VDMA driver.
If this will turn out to be the case, and it will be fixed, then maybe
removing this remaining custom-stuff would be possible.

Signed-off-by: Andrea Merello <[email protected]>
We don't need anymore the old, not-mainlined VDMA driver.
Update the "compatible" string for the VDMA IP so that the mainline
VDMA driver will catch it.
Remove also a child property that was set to zero, but become boolean
in the new VDMA driver.

Signed-off-by: Andrea Merello <[email protected]>
The mainline VDMA driver does not overload the dma_slave_config
struct, instead it exports it's own configuration function.
Thus, since we call it, we require the VDMA driver to be also
compiled in order to avoid linking error.

I didn't worry too much about having this unconditionally required,
even if we still support also the old VDMA driver, because hopefully
this is transitory situation, and I hope the old driver will go
away; currently we still support it mainly to care about pepole
who may update kernel while keeping the old DT.

Signed-off-by: Andrea Merello <[email protected]>
@lclausen-adi
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Hi,

Thanks a lot for doing this. I've applied the patches. I slightly changed the order and also squashed the 'select' patch into the other patch to avoid the linker error from ever occurring. Also adjusted the patch subjects to match the subsystem preferred style.

I agree that it is not nice that we have to use the custom config function. The main issue is that the DMAEngine API does not offer a way to setup a cyclic interleaved transfer like we want it in this case. If we extend the DMAEngine API to allow this we can get rid of the custom config function.

  • Lars

mhennerich pushed a commit that referenced this pull request Apr 5, 2016
Fixes segmentation fault using, for instance:

  (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib64/libthread_db.so.1".

 Program received signal SIGSEGV, Segmentation fault.
  0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  (gdb) bt
  #0  0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  #1  0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:433
  #2  0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:498
  #3  0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:936
  #4  0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391
  #5  0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361
  #6  0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401
  #7  0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253
  #8  0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364
  #9  0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664
  #10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539
  #11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264
  #12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390
  #13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451
  #14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495
  #15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618
(gdb)

Intel PT attempts to find the sched:sched_switch tracepoint but that seg
faults if tracefs is not readable, because the error reporting structure
is null, as errors are not reported when automatically adding
tracepoints.  Fix by checking before using.

Committer note:

This doesn't take place in a kernel that supports
perf_event_attr.context_switch, that is the default way that will be
used for tracking context switches, only in older kernels, like 4.2, in
a machine with Intel PT (e.g. Broadwell) for non-priviledged users.

Further info from a similar patch by Wang:

The error is in tracepoint_error: it assumes the 'e' parameter is valid.

However, there are many situation a parse_event() can be called without
parse_events_error. See result of

  $ grep 'parse_events(.*NULL)' ./tools/perf/ -r'

Signed-off-by: Adrian Hunter <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Tong Zhang <[email protected]>
Cc: Wang Nan <[email protected]>
Cc: [email protected] # v4.4+
Fixes: 1965817 ("perf tools: Enhance parsing events tracepoint error output")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
commodo pushed a commit that referenced this pull request Apr 26, 2018
[ Upstream commit 191f86c ]

The seg6_build_state() function is called with RCU read lock held,
so we cannot use GFP_KERNEL. This patch uses GFP_ATOMIC instead.

[   92.770271] =============================
[   92.770628] WARNING: suspicious RCU usage
[   92.770921] 4.16.0-rc4+ #12 Not tainted
[   92.771277] -----------------------------
[   92.771585] ./include/linux/rcupdate.h:302 Illegal context switch in RCU read-side critical section!
[   92.772279]
[   92.772279] other info that might help us debug this:
[   92.772279]
[   92.773067]
[   92.773067] rcu_scheduler_active = 2, debug_locks = 1
[   92.773514] 2 locks held by ip/2413:
[   92.773765]  #0:  (rtnl_mutex){+.+.}, at: [<00000000e5461720>] rtnetlink_rcv_msg+0x441/0x4d0
[   92.774377]  #1:  (rcu_read_lock){....}, at: [<00000000df4f161e>] lwtunnel_build_state+0x59/0x210
[   92.775065]
[   92.775065] stack backtrace:
[   92.775371] CPU: 0 PID: 2413 Comm: ip Not tainted 4.16.0-rc4+ #12
[   92.775791] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014
[   92.776608] Call Trace:
[   92.776852]  dump_stack+0x7d/0xbc
[   92.777130]  __schedule+0x133/0xf00
[   92.777393]  ? unwind_get_return_address_ptr+0x50/0x50
[   92.777783]  ? __sched_text_start+0x8/0x8
[   92.778073]  ? rcu_is_watching+0x19/0x30
[   92.778383]  ? kernel_text_address+0x49/0x60
[   92.778800]  ? __kernel_text_address+0x9/0x30
[   92.779241]  ? unwind_get_return_address+0x29/0x40
[   92.779727]  ? pcpu_alloc+0x102/0x8f0
[   92.780101]  _cond_resched+0x23/0x50
[   92.780459]  __mutex_lock+0xbd/0xad0
[   92.780818]  ? pcpu_alloc+0x102/0x8f0
[   92.781194]  ? seg6_build_state+0x11d/0x240
[   92.781611]  ? save_stack+0x9b/0xb0
[   92.781965]  ? __ww_mutex_wakeup_for_backoff+0xf0/0xf0
[   92.782480]  ? seg6_build_state+0x11d/0x240
[   92.782925]  ? lwtunnel_build_state+0x1bd/0x210
[   92.783393]  ? ip6_route_info_create+0x687/0x1640
[   92.783846]  ? ip6_route_add+0x74/0x110
[   92.784236]  ? inet6_rtm_newroute+0x8a/0xd0

Fixes: 6c8702c ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Signed-off-by: David Lebrun <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
commodo pushed a commit that referenced this pull request Aug 7, 2018
Crash dump shows following instructions

crash> bt
PID: 0      TASK: ffffffffbe412480  CPU: 0   COMMAND: "swapper/0"
 #0 [ffff891ee0003868] machine_kexec at ffffffffbd063ef1
 #1 [ffff891ee00038c8] __crash_kexec at ffffffffbd12b6f2
 #2 [ffff891ee0003998] crash_kexec at ffffffffbd12c84c
 #3 [ffff891ee00039b8] oops_end at ffffffffbd030f0a
 #4 [ffff891ee00039e0] no_context at ffffffffbd074643
 #5 [ffff891ee0003a40] __bad_area_nosemaphore at ffffffffbd07496e
 #6 [ffff891ee0003a90] bad_area_nosemaphore at ffffffffbd074a64
 #7 [ffff891ee0003aa0] __do_page_fault at ffffffffbd074b0a
 #8 [ffff891ee0003b18] do_page_fault at ffffffffbd074fc8
 #9 [ffff891ee0003b50] page_fault at ffffffffbda01925
    [exception RIP: qlt_schedule_sess_for_deletion+15]
    RIP: ffffffffc02e526f  RSP: ffff891ee0003c08  RFLAGS: 00010046
    RAX: 0000000000000000  RBX: 0000000000000000  RCX: ffffffffc0307847
    RDX: 00000000000020e6  RSI: ffff891edbc377c8  RDI: 0000000000000000
    RBP: ffff891ee0003c18   R8: ffffffffc02f0b20   R9: 0000000000000250
    R10: 0000000000000258  R11: 000000000000b780  R12: ffff891ed9b43000
    R13: 00000000000000f0  R14: 0000000000000006  R15: ffff891edbc377c8
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #10 [ffff891ee0003c20] qla2x00_fcport_event_handler at ffffffffc02853d3 [qla2xxx]
 #11 [ffff891ee0003cf0] __dta_qla24xx_async_gnl_sp_done_333 at ffffffffc0285a1d [qla2xxx]
 #12 [ffff891ee0003de8] qla24xx_process_response_queue at ffffffffc02a2eb5 [qla2xxx]
 #13 [ffff891ee0003e88] qla24xx_msix_rsp_q at ffffffffc02a5403 [qla2xxx]
 #14 [ffff891ee0003ec0] __handle_irq_event_percpu at ffffffffbd0f4c59
 #15 [ffff891ee0003f10] handle_irq_event_percpu at ffffffffbd0f4e02
 #16 [ffff891ee0003f40] handle_irq_event at ffffffffbd0f4e90
 #17 [ffff891ee0003f68] handle_edge_irq at ffffffffbd0f8984
 #18 [ffff891ee0003f88] handle_irq at ffffffffbd0305d5
 #19 [ffff891ee0003fb8] do_IRQ at ffffffffbda02a18
 --- <IRQ stack> ---
 #20 [ffffffffbe403d30] ret_from_intr at ffffffffbda0094e
    [exception RIP: unknown or invalid address]
    RIP: 000000000000001f  RSP: 0000000000000000  RFLAGS: fff3b8c2091ebb3f
    RAX: ffffbba5a0000200  RBX: 0000be8cdfa8f9fa  RCX: 0000000000000018
    RDX: 0000000000000101  RSI: 000000000000015d  RDI: 0000000000000193
    RBP: 0000000000000083   R8: ffffffffbe403e38   R9: 0000000000000002
    R10: 0000000000000000  R11: ffffffffbe56b820  R12: ffff891ee001cf00
    R13: ffffffffbd11c0a4  R14: ffffffffbe403d60  R15: 0000000000000001
    ORIG_RAX: ffff891ee0022ac0  CS: 0000  SS: ffffffffffffffb9
 bt: WARNING: possibly bogus exception frame
 #21 [ffffffffbe403dd8] cpuidle_enter_state at ffffffffbd67c6fd
 #22 [ffffffffbe403e40] cpuidle_enter at ffffffffbd67c907
 #23 [ffffffffbe403e50] call_cpuidle at ffffffffbd0d98f3
 #24 [ffffffffbe403e60] do_idle at ffffffffbd0d9b42
 #25 [ffffffffbe403e98] cpu_startup_entry at ffffffffbd0d9da3
 #26 [ffffffffbe403ec0] rest_init at ffffffffbd81d4aa
 #27 [ffffffffbe403ed0] start_kernel at ffffffffbe67d2ca
 #28 [ffffffffbe403f28] x86_64_start_reservations at ffffffffbe67c675
 #29 [ffffffffbe403f38] x86_64_start_kernel at ffffffffbe67c6eb
 #30 [ffffffffbe403f50] secondary_startup_64 at ffffffffbd0000d5

Fixes: 040036b ("scsi: qla2xxx: Delay loop id allocation at login")
Cc: <[email protected]> # v4.17+
Signed-off-by: Chuck Anderson <[email protected]>
Signed-off-by: Himanshu Madhani <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
commodo pushed a commit that referenced this pull request Oct 2, 2019
A deadlock with this stacktrace was observed.

The loop thread does a GFP_KERNEL allocation, it calls into dm-bufio
shrinker and the shrinker depends on I/O completion in the dm-bufio
subsystem.

In order to fix the deadlock (and other similar ones), we set the flag
PF_MEMALLOC_NOIO at loop thread entry.

PID: 474    TASK: ffff8813e11f4600  CPU: 10  COMMAND: "kswapd0"
   #0 [ffff8813dedfb938] __schedule at ffffffff8173f405
   #1 [ffff8813dedfb990] schedule at ffffffff8173fa27
   #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
   #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
   #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
   #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
   #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
   #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
   #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
   #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
  #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
  #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
  #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
  #13 [ffff8813dedfbec0] kthread at ffffffff810a8428
  #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242

  PID: 14127  TASK: ffff881455749c00  CPU: 11  COMMAND: "loop1"
   #0 [ffff88272f5af228] __schedule at ffffffff8173f405
   #1 [ffff88272f5af280] schedule at ffffffff8173fa27
   #2 [ffff88272f5af2a0] schedule_preempt_disabled at ffffffff8173fd5e
   #3 [ffff88272f5af2b0] __mutex_lock_slowpath at ffffffff81741fb5
   #4 [ffff88272f5af330] mutex_lock at ffffffff81742133
   #5 [ffff88272f5af350] dm_bufio_shrink_count at ffffffffa03865f9 [dm_bufio]
   #6 [ffff88272f5af380] shrink_slab at ffffffff811a86bd
   #7 [ffff88272f5af470] shrink_zone at ffffffff811ad778
   #8 [ffff88272f5af500] do_try_to_free_pages at ffffffff811adb34
   #9 [ffff88272f5af590] try_to_free_pages at ffffffff811adef8
  #10 [ffff88272f5af610] __alloc_pages_nodemask at ffffffff811a09c3
  #11 [ffff88272f5af710] alloc_pages_current at ffffffff811e8b71
  #12 [ffff88272f5af760] new_slab at ffffffff811f4523
  #13 [ffff88272f5af7b0] __slab_alloc at ffffffff8173a1b5
  #14 [ffff88272f5af880] kmem_cache_alloc at ffffffff811f484b
  #15 [ffff88272f5af8d0] do_blockdev_direct_IO at ffffffff812535b3
  #16 [ffff88272f5afb00] __blockdev_direct_IO at ffffffff81255dc3
  #17 [ffff88272f5afb30] xfs_vm_direct_IO at ffffffffa01fe3fc [xfs]
  #18 [ffff88272f5afb90] generic_file_read_iter at ffffffff81198994
  #19 [ffff88272f5afc50] __dta_xfs_file_read_iter_2398 at ffffffffa020c970 [xfs]
  #20 [ffff88272f5afcc0] lo_rw_aio at ffffffffa0377042 [loop]
  #21 [ffff88272f5afd70] loop_queue_work at ffffffffa0377c3b [loop]
  #22 [ffff88272f5afe60] kthread_worker_fn at ffffffff810a8a0c
  #23 [ffff88272f5afec0] kthread at ffffffff810a8428
  #24 [ffff88272f5aff50] ret_from_fork at ffffffff81745242

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Signed-off-by: Jens Axboe <[email protected]>
commodo pushed a commit that referenced this pull request Nov 25, 2019
The mkey_table xarray is touched by the reg_mr_callback() function which
is called from a hard irq. Thus all other uses of xa_lock must use the
_irq variants.

  WARNING: inconsistent lock state
  5.4.0-rc1 #12 Not tainted
  --------------------------------
  inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
  python3/343 [HC0[0]:SC0[0]:HE1:SE1] takes:
  ffff888182be1d40 (&(&xa->xa_lock)->rlock#3){?.-.}, at: xa_erase+0x12/0x30
  {IN-HARDIRQ-W} state was registered at:
    lock_acquire+0xe1/0x200
    _raw_spin_lock_irqsave+0x35/0x50
    reg_mr_callback+0x2dd/0x450 [mlx5_ib]
    mlx5_cmd_exec_cb_handler+0x2c/0x70 [mlx5_core]
    mlx5_cmd_comp_handler+0x355/0x840 [mlx5_core]
   [..]

   Possible unsafe locking scenario:

         CPU0
         ----
    lock(&(&xa->xa_lock)->rlock#3);
    <Interrupt>
      lock(&(&xa->xa_lock)->rlock#3);

   *** DEADLOCK ***

  2 locks held by python3/343:
   #0: ffff88818eb4bd38 (&uverbs_dev->disassociate_srcu){....}, at: ib_uverbs_ioctl+0xe5/0x1e0 [ib_uverbs]
   #1: ffff888176c76d38 (&file->hw_destroy_rwsem){++++}, at: uobj_destroy+0x2d/0x90 [ib_uverbs]

  stack backtrace:
  CPU: 3 PID: 343 Comm: python3 Not tainted 5.4.0-rc1 #12
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
  Call Trace:
   dump_stack+0x86/0xca
   print_usage_bug.cold.50+0x2e5/0x355
   mark_lock+0x871/0xb50
   ? match_held_lock+0x20/0x250
   ? check_usage_forwards+0x240/0x240
   __lock_acquire+0x7de/0x23a0
   ? __kasan_check_read+0x11/0x20
   ? mark_lock+0xae/0xb50
   ? mark_held_locks+0xb0/0xb0
   ? find_held_lock+0xca/0xf0
   lock_acquire+0xe1/0x200
   ? xa_erase+0x12/0x30
   _raw_spin_lock+0x2a/0x40
   ? xa_erase+0x12/0x30
   xa_erase+0x12/0x30
   mlx5_ib_dealloc_mw+0x55/0xa0 [mlx5_ib]
   uverbs_dealloc_mw+0x3c/0x70 [ib_uverbs]
   uverbs_free_mw+0x1a/0x20 [ib_uverbs]
   destroy_hw_idr_uobject+0x49/0xa0 [ib_uverbs]
   [..]

Fixes: 0417791 ("RDMA/mlx5: Add missing synchronize_srcu() for MW cases")
Link: https://lore.kernel.org/r/[email protected]
Acked-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
commodo pushed a commit that referenced this pull request Sep 10, 2020
…s metrics" test

Linux 5.9 introduced perf test case "Parse and process metrics" and
on s390 this test case always dumps core:

  [root@t35lp67 perf]# ./perf test -vvvv -F 67
  67: Parse and process metrics                             :
  --- start ---
  metric expr inst_retired.any / cpu_clk_unhalted.thread for IPC
  parsing metric: inst_retired.any / cpu_clk_unhalted.thread
  Segmentation fault (core dumped)
  [root@t35lp67 perf]#

I debugged this core dump and gdb shows this call chain:

  (gdb) where
   #0  0x000003ffabc3192a in __strnlen_c_1 () from /lib64/libc.so.6
   #1  0x000003ffabc293de in strcasestr () from /lib64/libc.so.6
   #2  0x0000000001102ba2 in match_metric(list=0x1e6ea20 "inst_retired.any",
            n=<optimized out>)
       at util/metricgroup.c:368
   #3  find_metric (map=<optimized out>, map=<optimized out>,
           metric=0x1e6ea20 "inst_retired.any")
      at util/metricgroup.c:765
   #4  __resolve_metric (ids=0x0, map=<optimized out>, metric_list=0x0,
           metric_no_group=<optimized out>, m=<optimized out>)
      at util/metricgroup.c:844
   #5  resolve_metric (ids=0x0, map=0x0, metric_list=0x0,
          metric_no_group=<optimized out>)
      at util/metricgroup.c:881
   #6  metricgroup__add_metric (metric=<optimized out>,
        metric_no_group=metric_no_group@entry=false, events=<optimized out>,
        events@entry=0x3ffd84fb878, metric_list=0x0,
        metric_list@entry=0x3ffd84fb868, map=0x0)
      at util/metricgroup.c:943
   #7  0x00000000011034ae in metricgroup__add_metric_list (map=0x13f9828 <map>,
        metric_list=0x3ffd84fb868, events=0x3ffd84fb878,
        metric_no_group=<optimized out>, list=<optimized out>)
      at util/metricgroup.c:988
   #8  parse_groups (perf_evlist=perf_evlist@entry=0x1e70260,
          str=str@entry=0x12f34b2 "IPC", metric_no_group=<optimized out>,
          metric_no_merge=<optimized out>,
          fake_pmu=fake_pmu@entry=0x1462f18 <perf_pmu.fake>,
          metric_events=0x3ffd84fba58, map=0x1)
      at util/metricgroup.c:1040
   #9  0x0000000001103eb2 in metricgroup__parse_groups_test(
  	evlist=evlist@entry=0x1e70260, map=map@entry=0x13f9828 <map>,
  	str=str@entry=0x12f34b2 "IPC",
  	metric_no_group=metric_no_group@entry=false,
  	metric_no_merge=metric_no_merge@entry=false,
  	metric_events=0x3ffd84fba58)
      at util/metricgroup.c:1082
   #10 0x00000000010c84d8 in __compute_metric (ratio2=0x0, name2=0x0,
          ratio1=<synthetic pointer>, name1=0x12f34b2 "IPC",
  	vals=0x3ffd84fbad8, name=0x12f34b2 "IPC")
      at tests/parse-metric.c:159
   #11 compute_metric (ratio=<synthetic pointer>, vals=0x3ffd84fbad8,
  	name=0x12f34b2 "IPC")
      at tests/parse-metric.c:189
   #12 test_ipc () at tests/parse-metric.c:208
.....
..... omitted many more lines

This test case was added with
commit 218ca91 ("perf tests: Add parse metric test for frontend metric").

When I compile with make DEBUG=y it works fine and I do not get a core dump.

It turned out that the above listed function call chain worked on a struct
pmu_event array which requires a trailing element with zeroes which was
missing. The marco map_for_each_event() loops over that array tests for members
metric_expr/metric_name/metric_group being non-NULL. Adding this element fixes
the issue.

Output after:

  [root@t35lp46 perf]# ./perf test 67
  67: Parse and process metrics                             : Ok
  [root@t35lp46 perf]#

Committer notes:

As Ian remarks, this is not s390 specific:

<quote Ian>
  This also shows up with address sanitizer on all architectures
  (perhaps change the patch title) and perhaps add a "Fixes: <commit>"
  tag.

  =================================================================
  ==4718==ERROR: AddressSanitizer: global-buffer-overflow on address
  0x55c93b4d59e8 at pc 0x55c93a1541e2 bp 0x7ffd24327c60 sp
  0x7ffd24327c58
  READ of size 8 at 0x55c93b4d59e8 thread T0
      #0 0x55c93a1541e1 in find_metric tools/perf/util/metricgroup.c:764:2
      #1 0x55c93a153e6c in __resolve_metric tools/perf/util/metricgroup.c:844:9
      #2 0x55c93a152f18 in resolve_metric tools/perf/util/metricgroup.c:881:9
      #3 0x55c93a1528db in metricgroup__add_metric
  tools/perf/util/metricgroup.c:943:9
      #4 0x55c93a151996 in metricgroup__add_metric_list
  tools/perf/util/metricgroup.c:988:9
      #5 0x55c93a1511b9 in parse_groups tools/perf/util/metricgroup.c:1040:8
      #6 0x55c93a1513e1 in metricgroup__parse_groups_test
  tools/perf/util/metricgroup.c:1082:9
      #7 0x55c93a0108ae in __compute_metric tools/perf/tests/parse-metric.c:159:8
      #8 0x55c93a010744 in compute_metric tools/perf/tests/parse-metric.c:189:9
      #9 0x55c93a00f5ee in test_ipc tools/perf/tests/parse-metric.c:208:2
      #10 0x55c93a00f1e8 in test__parse_metric
  tools/perf/tests/parse-metric.c:345:2
      #11 0x55c939fd7202 in run_test tools/perf/tests/builtin-test.c:410:9
      #12 0x55c939fd6736 in test_and_print tools/perf/tests/builtin-test.c:440:9
      #13 0x55c939fd58c3 in __cmd_test tools/perf/tests/builtin-test.c:661:4
      #14 0x55c939fd4e02 in cmd_test tools/perf/tests/builtin-test.c:807:9
      #15 0x55c939e4763d in run_builtin tools/perf/perf.c:313:11
      #16 0x55c939e46475 in handle_internal_command tools/perf/perf.c:365:8
      #17 0x55c939e4737e in run_argv tools/perf/perf.c:409:2
      #18 0x55c939e45f7e in main tools/perf/perf.c:539:3

  0x55c93b4d59e8 is located 0 bytes to the right of global variable
  'pme_test' defined in 'tools/perf/tests/parse-metric.c:17:25'
  (0x55c93b4d54a0) of size 1352
  SUMMARY: AddressSanitizer: global-buffer-overflow
  tools/perf/util/metricgroup.c:764:2 in find_metric
  Shadow bytes around the buggy address:
    0x0ab9a7692ae0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692af0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  =>0x0ab9a7692b30: 00 00 00 00 00 00 00 00 00 00 00 00 00[f9]f9 f9
    0x0ab9a7692b40: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
    0x0ab9a7692b50: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
    0x0ab9a7692b60: f9 f9 f9 f9 f9 f9 f9 f9 00 00 00 00 00 00 00 00
    0x0ab9a7692b70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
  Shadow byte legend (one shadow byte represents 8 application bytes):
    Addressable:           00
    Partially addressable: 01 02 03 04 05 06 07
    Heap left redzone:	   fa
    Freed heap region:	   fd
    Stack left redzone:	   f1
    Stack mid redzone:	   f2
    Stack right redzone:     f3
    Stack after return:	   f5
    Stack use after scope:   f8
    Global redzone:          f9
    Global init order:	   f6
    Poisoned by user:        f7
    Container overflow:	   fc
    Array cookie:            ac
    Intra object redzone:    bb
    ASan internal:           fe
    Left alloca redzone:     ca
    Right alloca redzone:    cb
    Shadow gap:              cc
</quote>

I'm also adding the missing "Fixes" tag and setting just .name to NULL,
as doing it that way is more compact (the compiler will zero out
everything else) and the table iterators look for .name being NULL as
the sentinel marking the end of the table.

Fixes: 0a507af ("perf tests: Add parse metric test for ipc metric")
Signed-off-by: Thomas Richter <[email protected]>
Reviewed-by: Sumanth Korikkar <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
commodo pushed a commit that referenced this pull request Sep 10, 2020
We've met softlockup with "CONFIG_PREEMPT_NONE=y", when the target memcg
doesn't have any reclaimable memory.

It can be easily reproduced as below:

  watchdog: BUG: soft lockup - CPU#0 stuck for 111s![memcg_test:2204]
  CPU: 0 PID: 2204 Comm: memcg_test Not tainted 5.9.0-rc2+ #12
  Call Trace:
    shrink_lruvec+0x49f/0x640
    shrink_node+0x2a6/0x6f0
    do_try_to_free_pages+0xe9/0x3e0
    try_to_free_mem_cgroup_pages+0xef/0x1f0
    try_charge+0x2c1/0x750
    mem_cgroup_charge+0xd7/0x240
    __add_to_page_cache_locked+0x2fd/0x370
    add_to_page_cache_lru+0x4a/0xc0
    pagecache_get_page+0x10b/0x2f0
    filemap_fault+0x661/0xad0
    ext4_filemap_fault+0x2c/0x40
    __do_fault+0x4d/0xf9
    handle_mm_fault+0x1080/0x1790

It only happens on our 1-vcpu instances, because there's no chance for
oom reaper to run to reclaim the to-be-killed process.

Add a cond_resched() at the upper shrink_node_memcgs() to solve this
issue, this will mean that we will get a scheduling point for each memcg
in the reclaimed hierarchy without any dependency on the reclaimable
memory in that memcg thus making it more predictable.

Suggested-by: Michal Hocko <[email protected]>
Signed-off-by: Xunlei Pang <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Chris Down <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
nunojsa pushed a commit that referenced this pull request Mar 13, 2023
This reverts commit bbaf971.

The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.

Example stacktrace with ZSTD on a 32bit ARM machine:

  Unable to handle kernel NULL pointer dereference at virtual address 00000000
  pgd = c4159ed3
  [00000000] *pgd=00000000
  Internal error: Oops: 5 [#1] PREEMPT SMP ARM
  Modules linked in:
  CPU: 0 PID: 210 Comm: kworker/u2:3 Not tainted 5.14.0-rc79+ #12
  Hardware name: Allwinner sun4i/sun5i Families
  Workqueue: btrfs-delalloc btrfs_work_helper
  PC is at mmiocpy+0x48/0x330
  LR is at ZSTD_compressStream_generic+0x15c/0x28c

  (mmiocpy) from [<c0629648>] (ZSTD_compressStream_generic+0x15c/0x28c)
  (ZSTD_compressStream_generic) from [<c06297dc>] (ZSTD_compressStream+0x64/0xa0)
  (ZSTD_compressStream) from [<c049444c>] (zstd_compress_pages+0x170/0x488)
  (zstd_compress_pages) from [<c0496798>] (btrfs_compress_pages+0x124/0x12c)
  (btrfs_compress_pages) from [<c043c068>] (compress_file_range+0x3c0/0x834)
  (compress_file_range) from [<c043c4ec>] (async_cow_start+0x10/0x28)
  (async_cow_start) from [<c0475c3c>] (btrfs_work_helper+0x100/0x230)
  (btrfs_work_helper) from [<c014ef68>] (process_one_work+0x1b4/0x418)
  (process_one_work) from [<c014f210>] (worker_thread+0x44/0x524)
  (worker_thread) from [<c0156aa4>] (kthread+0x180/0x1b0)
  (kthread) from [<c0100150>]

Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Signed-off-by: David Sterba <[email protected]>
btogorean pushed a commit that referenced this pull request Aug 25, 2023
[ Upstream commit 93c660c ]

ASAN reports an use-after-free in btf_dump_name_dups:

ERROR: AddressSanitizer: heap-use-after-free on address 0xffff927006db at pc 0xaaaab5dfb618 bp 0xffffdd89b890 sp 0xffffdd89b928
READ of size 2 at 0xffff927006db thread T0
    #0 0xaaaab5dfb614 in __interceptor_strcmp.part.0 (test_progs+0x21b614)
    #1 0xaaaab635f144 in str_equal_fn tools/lib/bpf/btf_dump.c:127
    #2 0xaaaab635e3e0 in hashmap_find_entry tools/lib/bpf/hashmap.c:143
    #3 0xaaaab635e72c in hashmap__find tools/lib/bpf/hashmap.c:212
    #4 0xaaaab6362258 in btf_dump_name_dups tools/lib/bpf/btf_dump.c:1525
    #5 0xaaaab636240c in btf_dump_resolve_name tools/lib/bpf/btf_dump.c:1552
    #6 0xaaaab6362598 in btf_dump_type_name tools/lib/bpf/btf_dump.c:1567
    #7 0xaaaab6360b48 in btf_dump_emit_struct_def tools/lib/bpf/btf_dump.c:912
    #8 0xaaaab6360630 in btf_dump_emit_type tools/lib/bpf/btf_dump.c:798
    #9 0xaaaab635f720 in btf_dump__dump_type tools/lib/bpf/btf_dump.c:282
    #10 0xaaaab608523c in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:236
    #11 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #12 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #13 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #14 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #15 0xaaaab5d65990  (test_progs+0x185990)

0xffff927006db is located 11 bytes inside of 16-byte region [0xffff927006d0,0xffff927006e0)
freed by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353e10 in btf__add_field tools/lib/bpf/btf.c:2032
    #7 0xaaaab6084fcc in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:232
    #8 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #9 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #10 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #11 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #12 0xaaaab5d65990  (test_progs+0x185990)

previously allocated by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353ff0 in btf_add_enum_common tools/lib/bpf/btf.c:2070
    #7 0xaaaab6354080 in btf__add_enum tools/lib/bpf/btf.c:2102
    #8 0xaaaab6082f50 in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:162
    #9 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #10 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #11 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #12 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #13 0xaaaab5d65990  (test_progs+0x185990)

The reason is that the key stored in hash table name_map is a string
address, and the string memory is allocated by realloc() function, when
the memory is resized by realloc() later, the old memory may be freed,
so the address stored in name_map references to a freed memory, causing
use-after-free.

Fix it by storing duplicated string address in name_map.

Fixes: 919d2b1 ("libbpf: Allow modification of BTF and add btf__add_str API")
Signed-off-by: Xu Kuohai <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
btogorean pushed a commit that referenced this pull request Aug 25, 2023
…g the sock

[ Upstream commit 3cf7203 ]

There is a race condition in vxlan that when deleting a vxlan device
during receiving packets, there is a possibility that the sock is
released after getting vxlan_sock vs from sk_user_data. Then in
later vxlan_ecn_decapsulate(), vxlan_get_sk_family() we will got
NULL pointer dereference. e.g.

   #0 [ffffa25ec6978a38] machine_kexec at ffffffff8c669757
   #1 [ffffa25ec6978a90] __crash_kexec at ffffffff8c7c0a4d
   #2 [ffffa25ec6978b58] crash_kexec at ffffffff8c7c1c48
   #3 [ffffa25ec6978b60] oops_end at ffffffff8c627f2b
   #4 [ffffa25ec6978b80] page_fault_oops at ffffffff8c678fcb
   #5 [ffffa25ec6978bd8] exc_page_fault at ffffffff8d109542
   #6 [ffffa25ec6978c00] asm_exc_page_fault at ffffffff8d200b62
      [exception RIP: vxlan_ecn_decapsulate+0x3b]
      RIP: ffffffffc1014e7b  RSP: ffffa25ec6978cb0  RFLAGS: 00010246
      RAX: 0000000000000008  RBX: ffff8aa000888000  RCX: 0000000000000000
      RDX: 000000000000000e  RSI: ffff8a9fc7ab803e  RDI: ffff8a9fd1168700
      RBP: ffff8a9fc7ab803e   R8: 0000000000700000   R9: 00000000000010ae
      R10: ffff8a9fcb748980  R11: 0000000000000000  R12: ffff8a9fd1168700
      R13: ffff8aa000888000  R14: 00000000002a0000  R15: 00000000000010ae
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #7 [ffffa25ec6978ce8] vxlan_rcv at ffffffffc10189cd [vxlan]
   #8 [ffffa25ec6978d90] udp_queue_rcv_one_skb at ffffffff8cfb6507
   #9 [ffffa25ec6978dc0] udp_unicast_rcv_skb at ffffffff8cfb6e45
  #10 [ffffa25ec6978dc8] __udp4_lib_rcv at ffffffff8cfb8807
  #11 [ffffa25ec6978e20] ip_protocol_deliver_rcu at ffffffff8cf76951
  #12 [ffffa25ec6978e48] ip_local_deliver at ffffffff8cf76bde
  #13 [ffffa25ec6978ea0] __netif_receive_skb_one_core at ffffffff8cecde9b
  #14 [ffffa25ec6978ec8] process_backlog at ffffffff8cece139
  #15 [ffffa25ec6978f00] __napi_poll at ffffffff8ceced1a
  #16 [ffffa25ec6978f28] net_rx_action at ffffffff8cecf1f3
  #17 [ffffa25ec6978fa0] __softirqentry_text_start at ffffffff8d4000ca
  #18 [ffffa25ec6978ff0] do_softirq at ffffffff8c6fbdc3

Reproducer: https://github.com/Mellanox/ovs-tests/blob/master/test-ovs-vxlan-remove-tunnel-during-traffic.sh

Fix this by waiting for all sk_user_data reader to finish before
releasing the sock.

Reported-by: Jianlin Shi <[email protected]>
Suggested-by: Jakub Sitnicki <[email protected]>
Fixes: 6a93cc9 ("udp-tunnel: Add a few more UDP tunnel APIs")
Signed-off-by: Hangbin Liu <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
nunojsa pushed a commit that referenced this pull request Nov 7, 2023
Fix an error detected by memory sanitizer:
```
==4033==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x55fb0fbedfc7 in read_alias_info tools/perf/util/pmu.c:457:6
    #1 0x55fb0fbea339 in check_info_data tools/perf/util/pmu.c:1434:2
    #2 0x55fb0fbea339 in perf_pmu__check_alias tools/perf/util/pmu.c:1504:9
    #3 0x55fb0fbdca85 in parse_events_add_pmu tools/perf/util/parse-events.c:1429:32
    #4 0x55fb0f965230 in parse_events_parse tools/perf/util/parse-events.y:299:6
    #5 0x55fb0fbdf6b2 in parse_events__scanner tools/perf/util/parse-events.c:1822:8
    #6 0x55fb0fbdf8c1 in __parse_events tools/perf/util/parse-events.c:2094:8
    #7 0x55fb0fa8ffa9 in parse_events tools/perf/util/parse-events.h:41:9
    #8 0x55fb0fa8ffa9 in test_event tools/perf/tests/parse-events.c:2393:8
    #9 0x55fb0fa8f458 in test__pmu_events tools/perf/tests/parse-events.c:2551:15
    #10 0x55fb0fa6d93f in run_test tools/perf/tests/builtin-test.c:242:9
    #11 0x55fb0fa6d93f in test_and_print tools/perf/tests/builtin-test.c:271:8
    #12 0x55fb0fa6d082 in __cmd_test tools/perf/tests/builtin-test.c:442:5
    #13 0x55fb0fa6d082 in cmd_test tools/perf/tests/builtin-test.c:564:9
    #14 0x55fb0f942720 in run_builtin tools/perf/perf.c:322:11
    #15 0x55fb0f942486 in handle_internal_command tools/perf/perf.c:375:8
    #16 0x55fb0f941dab in run_argv tools/perf/perf.c:419:2
    #17 0x55fb0f941dab in main tools/perf/perf.c:535:3
```

Fixes: 7b723db ("perf pmu: Be lazy about loading event info files from sysfs")
Signed-off-by: Ian Rogers <[email protected]>
Cc: James Clark <[email protected]>
Cc: Kan Liang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
nunojsa pushed a commit that referenced this pull request Nov 7, 2023
The following call trace shows a deadlock issue due to recursive locking of
mutex "device_mutex". First lock acquire is in target_for_each_device() and
second in target_free_device().

 PID: 148266   TASK: ffff8be21ffb5d00  CPU: 10   COMMAND: "iscsi_ttx"
  #0 [ffffa2bfc9ec3b18] __schedule at ffffffffa8060e7f
  #1 [ffffa2bfc9ec3ba0] schedule at ffffffffa8061224
  #2 [ffffa2bfc9ec3bb8] schedule_preempt_disabled at ffffffffa80615ee
  #3 [ffffa2bfc9ec3bc8] __mutex_lock at ffffffffa8062fd7
  #4 [ffffa2bfc9ec3c40] __mutex_lock_slowpath at ffffffffa80631d3
  #5 [ffffa2bfc9ec3c50] mutex_lock at ffffffffa806320c
  #6 [ffffa2bfc9ec3c68] target_free_device at ffffffffc0935998 [target_core_mod]
  #7 [ffffa2bfc9ec3c90] target_core_dev_release at ffffffffc092f975 [target_core_mod]
  #8 [ffffa2bfc9ec3ca0] config_item_put at ffffffffa79d250f
  #9 [ffffa2bfc9ec3cd0] config_item_put at ffffffffa79d2583
 #10 [ffffa2bfc9ec3ce0] target_devices_idr_iter at ffffffffc0933f3a [target_core_mod]
 #11 [ffffa2bfc9ec3d00] idr_for_each at ffffffffa803f6fc
 #12 [ffffa2bfc9ec3d60] target_for_each_device at ffffffffc0935670 [target_core_mod]
 #13 [ffffa2bfc9ec3d98] transport_deregister_session at ffffffffc0946408 [target_core_mod]
 #14 [ffffa2bfc9ec3dc8] iscsit_close_session at ffffffffc09a44a6 [iscsi_target_mod]
 #15 [ffffa2bfc9ec3df0] iscsit_close_connection at ffffffffc09a4a88 [iscsi_target_mod]
 #16 [ffffa2bfc9ec3df8] finish_task_switch at ffffffffa76e5d07
 #17 [ffffa2bfc9ec3e78] iscsit_take_action_for_connection_exit at ffffffffc0991c23 [iscsi_target_mod]
 #18 [ffffa2bfc9ec3ea0] iscsi_target_tx_thread at ffffffffc09a403b [iscsi_target_mod]
 #19 [ffffa2bfc9ec3f08] kthread at ffffffffa76d8080
 #20 [ffffa2bfc9ec3f50] ret_from_fork at ffffffffa8200364

Fixes: 36d4cb4 ("scsi: target: Avoid that EXTENDED COPY commands trigger lock inversion")
Signed-off-by: Junxiao Bi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
nunojsa pushed a commit that referenced this pull request Nov 7, 2023
Syzkaller reported the following issue:

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 2807 at mm/vmalloc.c:3247 __vmalloc_node_range (mm/vmalloc.c:3361)
  Modules linked in:
  CPU: 0 PID: 2807 Comm: repro Not tainted 6.6.0-rc2+ #12
  Hardware name: Generic DT based system
  unwind_backtrace from show_stack (arch/arm/kernel/traps.c:258)
  show_stack from dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1))
  dump_stack_lvl from __warn (kernel/panic.c:633 kernel/panic.c:680)
  __warn from warn_slowpath_fmt (./include/linux/context_tracking.h:153 kernel/panic.c:700)
  warn_slowpath_fmt from __vmalloc_node_range (mm/vmalloc.c:3361 (discriminator 3))
  __vmalloc_node_range from vmalloc_user (mm/vmalloc.c:3478)
  vmalloc_user from xskq_create (net/xdp/xsk_queue.c:40)
  xskq_create from xsk_setsockopt (net/xdp/xsk.c:953 net/xdp/xsk.c:1286)
  xsk_setsockopt from __sys_setsockopt (net/socket.c:2308)
  __sys_setsockopt from ret_fast_syscall (arch/arm/kernel/entry-common.S:68)

xskq_get_ring_size() uses struct_size() macro to safely calculate the
size of struct xsk_queue and q->nentries of desc members. But the
syzkaller repro was able to set q->nentries with the value initially
taken from copy_from_sockptr() high enough to return SIZE_MAX by
struct_size(). The next PAGE_ALIGN(size) is such case will overflow
the size_t value and set it to 0. This will trigger WARN_ON_ONCE in
vmalloc_user() -> __vmalloc_node_range().

The issue is reproducible on 32-bit arm kernel.

Fixes: 9f78bf3 ("xsk: support use vaddr as ring")
Reported-by: [email protected]
Closes: https://lore.kernel.org/all/[email protected]/T/
Reported-by: [email protected]
Closes: https://lore.kernel.org/all/[email protected]/T/
Signed-off-by: Andrew Kanner <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Tested-by: [email protected]
Acked-by: Magnus Karlsson <[email protected]>
Link: https://syzkaller.appspot.com/bug?extid=fae676d3cf469331fc89
Link: https://lore.kernel.org/bpf/[email protected]
nunojsa pushed a commit that referenced this pull request Jan 18, 2024
[ Upstream commit e82025c ]

Out-of-band data automatically places a "mark" showing wherein the
sequence the out-of-band data would have been.  If the out-of-band data
implies cancelling everything sent so far, the "mark" is helpful to flush
them.  When the socket's read pointer reaches the "mark", the ioctl() below
sets a non zero value to the arg `atmark`:

The out-of-band data is queued in sk->sk_receive_queue as well as ordinary
data and also saved in unix_sk(sk)->oob_skb.  It can be used to test if the
head of the receive queue is the out-of-band data meaning the socket is at
the "mark".

While testing that, unix_ioctl() reads unix_sk(sk)->oob_skb locklessly.
Thus, all accesses to oob_skb need some basic protection to avoid
load/store tearing which KCSAN detects when these are called concurrently:

  - ioctl(fd_a, SIOCATMARK, &atmark, sizeof(atmark))
  - send(fd_b_connected_to_a, buf, sizeof(buf), MSG_OOB)

BUG: KCSAN: data-race in unix_ioctl / unix_stream_sendmsg

write to 0xffff888003d9cff0 of 8 bytes by task 175 on cpu 1:
 unix_stream_sendmsg (net/unix/af_unix.c:2087 net/unix/af_unix.c:2191)
 sock_sendmsg (net/socket.c:705 net/socket.c:725)
 __sys_sendto (net/socket.c:2040)
 __x64_sys_sendto (net/socket.c:2048)
 do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:113)

read to 0xffff888003d9cff0 of 8 bytes by task 176 on cpu 0:
 unix_ioctl (net/unix/af_unix.c:3101 (discriminator 1))
 sock_do_ioctl (net/socket.c:1128)
 sock_ioctl (net/socket.c:1242)
 __x64_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:874 fs/ioctl.c:860 fs/ioctl.c:860)
 do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:113)

value changed: 0xffff888003da0c00 -> 0xffff888003da0d00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 176 Comm: unix_race_oob_i Not tainted 5.17.0-rc5-59529-g83dc4c2af682 #12
Hardware name: Red Hat KVM, BIOS 1.11.0-2.amzn2 04/01/2014

Fixes: 314001f ("af_unix: Add OOB support")
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
nunojsa pushed a commit that referenced this pull request Jan 18, 2024
[ Upstream commit fe2640b ]

In remove_phb_dynamic() we use &phb->io_resource, after we've called
device_unregister(&host_bridge->dev). But the unregister may have freed
phb, because pcibios_free_controller_deferred() is the release function
for the host_bridge.

If there are no outstanding references when we call device_unregister()
then phb will be freed out from under us.

This has gone mainly unnoticed, but with slub_debug and page_poison
enabled it can lead to a crash:

  PID: 7574   TASK: c0000000d492cb80  CPU: 13  COMMAND: "drmgr"
   #0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc
   #1 [c0000000e4f075d0] oops_end at c000000000029608
   #2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4
   #3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8
   #4 [c0000000e4f076f0] data_access_slb_common_virt at c000000000008b30
   Data SLB Access [380] exception frame:
   R0:  c000000000167250    R1:  c0000000e4f07a00    R2:  c000000002a46100
   R3:  c000000002b39ce8    R4:  00000000000000c0    R5:  00000000000000a9
   R6:  3894674d000000c0    R7:  0000000000000000    R8:  00000000000000ff
   R9:  0000000000000100    R10: 6b6b6b6b6b6b6b6b    R11: 0000000000008000
   R12: c00000000023da80    R13: c0000009ffd38b00    R14: 0000000000000000
   R15: 000000011c87f0f0    R16: 0000000000000006    R17: 0000000000000003
   R18: 0000000000000002    R19: 0000000000000004    R20: 0000000000000005
   R21: 000000011c87ede8    R22: 000000011c87c5a8    R23: 000000011c87d3a0
   R24: 0000000000000000    R25: 0000000000000001    R26: c0000000e4f07cc8
   R27: c00000004d1cc400    R28: c0080000031d00e8    R29: c00000004d23d800
   R30: c00000004d1d2400    R31: c00000004d1d2540
   NIP: c000000000167258    MSR: 8000000000009033    OR3: c000000000e9f474
   CTR: 0000000000000000    LR:  c000000000167250    XER: 0000000020040003
   CCR: 0000000024088420    MQ:  0000000000000000    DAR: 6b6b6b6b6b6b6ba3
   DSISR: c0000000e4f07920     Syscall Result: fffffffffffffff2
   [NIP  : release_resource+56]
   [LR   : release_resource+48]
   #5 [c0000000e4f07a00] release_resource at c000000000167258  (unreliable)
   #6 [c0000000e4f07a30] remove_phb_dynamic at c000000000105648
   #7 [c0000000e4f07ab0] dlpar_remove_slot at c0080000031a09e8 [rpadlpar_io]
   #8 [c0000000e4f07b50] remove_slot_store at c0080000031a0b9c [rpadlpar_io]
   #9 [c0000000e4f07be0] kobj_attr_store at c000000000817d8c
  #10 [c0000000e4f07c00] sysfs_kf_write at c00000000063e504
  #11 [c0000000e4f07c20] kernfs_fop_write_iter at c00000000063d868
  #12 [c0000000e4f07c70] new_sync_write at c00000000054339c
  #13 [c0000000e4f07d10] vfs_write at c000000000546624
  #14 [c0000000e4f07d60] ksys_write at c0000000005469f4
  #15 [c0000000e4f07db0] system_call_exception at c000000000030840
  #16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168

To avoid it, we can take a reference to the host_bridge->dev until we're
done using phb. Then when we drop the reference the phb will be freed.

Fixes: 2dd9c11 ("powerpc/pseries: use pci_host_bridge.release_fn() to kfree(phb)")
Reported-by: David Dai <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Tested-by: Sachin Sant <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
UtsavAgarwalADI pushed a commit that referenced this pull request Jun 28, 2024
…PLES event"

This reverts commit 7d1405c.

This causes segfaults in some cases, as reported by Milian:

  ```
  sudo /usr/bin/perf record -z --call-graph dwarf -e cycles -e
  raw_syscalls:sys_enter ls
  ...
  [ perf record: Woken up 3 times to write data ]
  malloc(): invalid next size (unsorted)
  Aborted
  ```

  Backtrace with GDB + debuginfod:

  ```
  malloc(): invalid next size (unsorted)

  Thread 1 "perf" received signal SIGABRT, Aborted.
  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6,
  no_tid=no_tid@entry=0) at pthread_kill.c:44
  Downloading source file /usr/src/debug/glibc/glibc/nptl/pthread_kill.c
  44            return INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO
  (ret) : 0;
  (gdb) bt
  #0  __pthread_kill_implementation (threadid=<optimized out>,
  signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
  #1  0x00007ffff6ea8eb3 in __pthread_kill_internal (threadid=<optimized out>,
  signo=6) at pthread_kill.c:78
  #2  0x00007ffff6e50a30 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/
  raise.c:26
  #3  0x00007ffff6e384c3 in __GI_abort () at abort.c:79
  #4  0x00007ffff6e39354 in __libc_message_impl (fmt=fmt@entry=0x7ffff6fc22ea
  "%s\n") at ../sysdeps/posix/libc_fatal.c:132
  #5  0x00007ffff6eb3085 in malloc_printerr (str=str@entry=0x7ffff6fc5850
  "malloc(): invalid next size (unsorted)") at malloc.c:5772
  #6  0x00007ffff6eb657c in _int_malloc (av=av@entry=0x7ffff6ff6ac0
  <main_arena>, bytes=bytes@entry=368) at malloc.c:4081
  #7  0x00007ffff6eb877e in __libc_calloc (n=<optimized out>,
  elem_size=<optimized out>) at malloc.c:3754
  #8  0x000055555569bdb6 in perf_session.do_write_header ()
  #9  0x00005555555a373a in __cmd_record.constprop.0 ()
  #10 0x00005555555a6846 in cmd_record ()
  #11 0x000055555564db7f in run_builtin ()
  #12 0x000055555558ed77 in main ()
  ```

  Valgrind memcheck:
  ```
  ==45136== Invalid write of size 8
  ==45136==    at 0x2B38A5: perf_event__synthesize_id_sample (in /usr/bin/perf)
  ==45136==    by 0x157069: __cmd_record.constprop.0 (in /usr/bin/perf)
  ==45136==    by 0x15A845: cmd_record (in /usr/bin/perf)
  ==45136==    by 0x201B7E: run_builtin (in /usr/bin/perf)
  ==45136==    by 0x142D76: main (in /usr/bin/perf)
  ==45136==  Address 0x6a866a8 is 0 bytes after a block of size 40 alloc'd
  ==45136==    at 0x4849BF3: calloc (vg_replace_malloc.c:1675)
  ==45136==    by 0x3574AB: zalloc (in /usr/bin/perf)
  ==45136==    by 0x1570E0: __cmd_record.constprop.0 (in /usr/bin/perf)
  ==45136==    by 0x15A845: cmd_record (in /usr/bin/perf)
  ==45136==    by 0x201B7E: run_builtin (in /usr/bin/perf)
  ==45136==    by 0x142D76: main (in /usr/bin/perf)
  ==45136==
  ==45136== Syscall param write(buf) points to unaddressable byte(s)
  ==45136==    at 0x575953D: __libc_write (write.c:26)
  ==45136==    by 0x575953D: write (write.c:24)
  ==45136==    by 0x35761F: ion (in /usr/bin/perf)
  ==45136==    by 0x357778: writen (in /usr/bin/perf)
  ==45136==    by 0x1548F7: record__write (in /usr/bin/perf)
  ==45136==    by 0x15708A: __cmd_record.constprop.0 (in /usr/bin/perf)
  ==45136==    by 0x15A845: cmd_record (in /usr/bin/perf)
  ==45136==    by 0x201B7E: run_builtin (in /usr/bin/perf)
  ==45136==    by 0x142D76: main (in /usr/bin/perf)
  ==45136==  Address 0x6a866a8 is 0 bytes after a block of size 40 alloc'd
  ==45136==    at 0x4849BF3: calloc (vg_replace_malloc.c:1675)
  ==45136==    by 0x3574AB: zalloc (in /usr/bin/perf)
  ==45136==    by 0x1570E0: __cmd_record.constprop.0 (in /usr/bin/perf)
  ==45136==    by 0x15A845: cmd_record (in /usr/bin/perf)
  ==45136==    by 0x201B7E: run_builtin (in /usr/bin/perf)
  ==45136==    by 0x142D76: main (in /usr/bin/perf)
  ==45136==
 -----

Closes: https://lore.kernel.org/linux-perf-users/23879991.0LEYPuXRzz@milian-workstation/
Reported-by: Milian Wolff <[email protected]>
Tested-by: Milian Wolff <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: [email protected] # 6.8+
Link: https://lore.kernel.org/lkml/Zl9ksOlHJHnKM70p@x1
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
UtsavAgarwalADI pushed a commit that referenced this pull request Jun 28, 2024
We have been seeing crashes on duplicate keys in
btrfs_set_item_key_safe():

  BTRFS critical (device vdb): slot 4 key (450 108 8192) new key (450 108 8192)
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/ctree.c:2620!
  invalid opcode: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 PID: 3139 Comm: xfs_io Kdump: loaded Not tainted 6.9.0 #6
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
  RIP: 0010:btrfs_set_item_key_safe+0x11f/0x290 [btrfs]

With the following stack trace:

  #0  btrfs_set_item_key_safe (fs/btrfs/ctree.c:2620:4)
  #1  btrfs_drop_extents (fs/btrfs/file.c:411:4)
  #2  log_one_extent (fs/btrfs/tree-log.c:4732:9)
  #3  btrfs_log_changed_extents (fs/btrfs/tree-log.c:4955:9)
  #4  btrfs_log_inode (fs/btrfs/tree-log.c:6626:9)
  #5  btrfs_log_inode_parent (fs/btrfs/tree-log.c:7070:8)
  #6  btrfs_log_dentry_safe (fs/btrfs/tree-log.c:7171:8)
  #7  btrfs_sync_file (fs/btrfs/file.c:1933:8)
  #8  vfs_fsync_range (fs/sync.c:188:9)
  #9  vfs_fsync (fs/sync.c:202:9)
  #10 do_fsync (fs/sync.c:212:9)
  #11 __do_sys_fdatasync (fs/sync.c:225:9)
  #12 __se_sys_fdatasync (fs/sync.c:223:1)
  #13 __x64_sys_fdatasync (fs/sync.c:223:1)
  #14 do_syscall_x64 (arch/x86/entry/common.c:52:14)
  #15 do_syscall_64 (arch/x86/entry/common.c:83:7)
  #16 entry_SYSCALL_64+0xaf/0x14c (arch/x86/entry/entry_64.S:121)

So we're logging a changed extent from fsync, which is splitting an
extent in the log tree. But this split part already exists in the tree,
triggering the BUG().

This is the state of the log tree at the time of the crash, dumped with
drgn (https://github.com/osandov/drgn/blob/main/contrib/btrfs_tree.py)
to get more details than btrfs_print_leaf() gives us:

  >>> print_extent_buffer(prog.crashed_thread().stack_trace()[0]["eb"])
  leaf 33439744 level 0 items 72 generation 9 owner 18446744073709551610
  leaf 33439744 flags 0x100000000000000
  fs uuid e5bd3946-400c-4223-8923-190ef1f18677
  chunk uuid d58cb17e-6d02-494a-829a-18b7d8a399da
          item 0 key (450 INODE_ITEM 0) itemoff 16123 itemsize 160
                  generation 7 transid 9 size 8192 nbytes 8473563889606862198
                  block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
                  sequence 204 flags 0x10(PREALLOC)
                  atime 1716417703.220000000 (2024-05-22 15:41:43)
                  ctime 1716417704.983333333 (2024-05-22 15:41:44)
                  mtime 1716417704.983333333 (2024-05-22 15:41:44)
                  otime 17592186044416.000000000 (559444-03-08 01:40:16)
          item 1 key (450 INODE_REF 256) itemoff 16110 itemsize 13
                  index 195 namelen 3 name: 193
          item 2 key (450 XATTR_ITEM 1640047104) itemoff 16073 itemsize 37
                  location key (0 UNKNOWN.0 0) type XATTR
                  transid 7 data_len 1 name_len 6
                  name: user.a
                  data a
          item 3 key (450 EXTENT_DATA 0) itemoff 16020 itemsize 53
                  generation 9 type 1 (regular)
                  extent data disk byte 303144960 nr 12288
                  extent data offset 0 nr 4096 ram 12288
                  extent compression 0 (none)
          item 4 key (450 EXTENT_DATA 4096) itemoff 15967 itemsize 53
                  generation 9 type 2 (prealloc)
                  prealloc data disk byte 303144960 nr 12288
                  prealloc data offset 4096 nr 8192
          item 5 key (450 EXTENT_DATA 8192) itemoff 15914 itemsize 53
                  generation 9 type 2 (prealloc)
                  prealloc data disk byte 303144960 nr 12288
                  prealloc data offset 8192 nr 4096
  ...

So the real problem happened earlier: notice that items 4 (4k-12k) and 5
(8k-12k) overlap. Both are prealloc extents. Item 4 straddles i_size and
item 5 starts at i_size.

Here is the state of the filesystem tree at the time of the crash:

  >>> root = prog.crashed_thread().stack_trace()[2]["inode"].root
  >>> ret, nodes, slots = btrfs_search_slot(root, BtrfsKey(450, 0, 0))
  >>> print_extent_buffer(nodes[0])
  leaf 30425088 level 0 items 184 generation 9 owner 5
  leaf 30425088 flags 0x100000000000000
  fs uuid e5bd3946-400c-4223-8923-190ef1f18677
  chunk uuid d58cb17e-6d02-494a-829a-18b7d8a399da
  	...
          item 179 key (450 INODE_ITEM 0) itemoff 4907 itemsize 160
                  generation 7 transid 7 size 4096 nbytes 12288
                  block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
                  sequence 6 flags 0x10(PREALLOC)
                  atime 1716417703.220000000 (2024-05-22 15:41:43)
                  ctime 1716417703.220000000 (2024-05-22 15:41:43)
                  mtime 1716417703.220000000 (2024-05-22 15:41:43)
                  otime 1716417703.220000000 (2024-05-22 15:41:43)
          item 180 key (450 INODE_REF 256) itemoff 4894 itemsize 13
                  index 195 namelen 3 name: 193
          item 181 key (450 XATTR_ITEM 1640047104) itemoff 4857 itemsize 37
                  location key (0 UNKNOWN.0 0) type XATTR
                  transid 7 data_len 1 name_len 6
                  name: user.a
                  data a
          item 182 key (450 EXTENT_DATA 0) itemoff 4804 itemsize 53
                  generation 9 type 1 (regular)
                  extent data disk byte 303144960 nr 12288
                  extent data offset 0 nr 8192 ram 12288
                  extent compression 0 (none)
          item 183 key (450 EXTENT_DATA 8192) itemoff 4751 itemsize 53
                  generation 9 type 2 (prealloc)
                  prealloc data disk byte 303144960 nr 12288
                  prealloc data offset 8192 nr 4096

Item 5 in the log tree corresponds to item 183 in the filesystem tree,
but nothing matches item 4. Furthermore, item 183 is the last item in
the leaf.

btrfs_log_prealloc_extents() is responsible for logging prealloc extents
beyond i_size. It first truncates any previously logged prealloc extents
that start beyond i_size. Then, it walks the filesystem tree and copies
the prealloc extent items to the log tree.

If it hits the end of a leaf, then it calls btrfs_next_leaf(), which
unlocks the tree and does another search. However, while the filesystem
tree is unlocked, an ordered extent completion may modify the tree. In
particular, it may insert an extent item that overlaps with an extent
item that was already copied to the log tree.

This may manifest in several ways depending on the exact scenario,
including an EEXIST error that is silently translated to a full sync,
overlapping items in the log tree, or this crash. This particular crash
is triggered by the following sequence of events:

- Initially, the file has i_size=4k, a regular extent from 0-4k, and a
  prealloc extent beyond i_size from 4k-12k. The prealloc extent item is
  the last item in its B-tree leaf.
- The file is fsync'd, which copies its inode item and both extent items
  to the log tree.
- An xattr is set on the file, which sets the
  BTRFS_INODE_COPY_EVERYTHING flag.
- The range 4k-8k in the file is written using direct I/O. i_size is
  extended to 8k, but the ordered extent is still in flight.
- The file is fsync'd. Since BTRFS_INODE_COPY_EVERYTHING is set, this
  calls copy_inode_items_to_log(), which calls
  btrfs_log_prealloc_extents().
- btrfs_log_prealloc_extents() finds the 4k-12k prealloc extent in the
  filesystem tree. Since it starts before i_size, it skips it. Since it
  is the last item in its B-tree leaf, it calls btrfs_next_leaf().
- btrfs_next_leaf() unlocks the path.
- The ordered extent completion runs, which converts the 4k-8k part of
  the prealloc extent to written and inserts the remaining prealloc part
  from 8k-12k.
- btrfs_next_leaf() does a search and finds the new prealloc extent
  8k-12k.
- btrfs_log_prealloc_extents() copies the 8k-12k prealloc extent into
  the log tree. Note that it overlaps with the 4k-12k prealloc extent
  that was copied to the log tree by the first fsync.
- fsync calls btrfs_log_changed_extents(), which tries to log the 4k-8k
  extent that was written.
- This tries to drop the range 4k-8k in the log tree, which requires
  adjusting the start of the 4k-12k prealloc extent in the log tree to
  8k.
- btrfs_set_item_key_safe() sees that there is already an extent
  starting at 8k in the log tree and calls BUG().

Fix this by detecting when we're about to insert an overlapping file
extent item in the log tree and truncating the part that would overlap.

CC: [email protected] # 6.1+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Omar Sandoval <[email protected]>
Signed-off-by: David Sterba <[email protected]>
dbogdan pushed a commit that referenced this pull request Jun 28, 2024
The code in ocfs2_dio_end_io_write() estimates number of necessary
transaction credits using ocfs2_calc_extend_credits().  This however does
not take into account that the IO could be arbitrarily large and can
contain arbitrary number of extents.

Extent tree manipulations do often extend the current transaction but not
in all of the cases.  For example if we have only single block extents in
the tree, ocfs2_mark_extent_written() will end up calling
ocfs2_replace_extent_rec() all the time and we will never extend the
current transaction and eventually exhaust all the transaction credits if
the IO contains many single block extents.  Once that happens a
WARN_ON(jbd2_handle_buffer_credits(handle) <= 0) is triggered in
jbd2_journal_dirty_metadata() and subsequently OCFS2 aborts in response to
this error.  This was actually triggered by one of our customers on a
heavily fragmented OCFS2 filesystem.

To fix the issue make sure the transaction always has enough credits for
one extent insert before each call of ocfs2_mark_extent_written().

Heming Zhao said:

------
PANIC: "Kernel panic - not syncing: OCFS2: (device dm-1): panic forced after error"

PID: xxx  TASK: xxxx  CPU: 5  COMMAND: "SubmitThread-CA"
  #0 machine_kexec at ffffffff8c069932
  #1 __crash_kexec at ffffffff8c1338fa
  #2 panic at ffffffff8c1d69b9
  #3 ocfs2_handle_error at ffffffffc0c86c0c [ocfs2]
  #4 __ocfs2_abort at ffffffffc0c88387 [ocfs2]
  #5 ocfs2_journal_dirty at ffffffffc0c51e98 [ocfs2]
  #6 ocfs2_split_extent at ffffffffc0c27ea3 [ocfs2]
  #7 ocfs2_change_extent_flag at ffffffffc0c28053 [ocfs2]
  #8 ocfs2_mark_extent_written at ffffffffc0c28347 [ocfs2]
  #9 ocfs2_dio_end_io_write at ffffffffc0c2bef9 [ocfs2]
#10 ocfs2_dio_end_io at ffffffffc0c2c0f5 [ocfs2]
#11 dio_complete at ffffffff8c2b9fa7
#12 do_blockdev_direct_IO at ffffffff8c2bc09f
#13 ocfs2_direct_IO at ffffffffc0c2b653 [ocfs2]
#14 generic_file_direct_write at ffffffff8c1dcf14
#15 __generic_file_write_iter at ffffffff8c1dd07b
#16 ocfs2_file_write_iter at ffffffffc0c49f1f [ocfs2]
#17 aio_write at ffffffff8c2cc72e
#18 kmem_cache_alloc at ffffffff8c248dde
#19 do_io_submit at ffffffff8c2ccada
#20 do_syscall_64 at ffffffff8c004984
#21 entry_SYSCALL_64_after_hwframe at ffffffff8c8000ba

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: c15471f ("ocfs2: fix sparse file & data ordering issue in direct io")
Signed-off-by: Jan Kara <[email protected]>
Reviewed-by: Joseph Qi <[email protected]>
Reviewed-by: Heming Zhao <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Changwei Ge <[email protected]>
Cc: Gang He <[email protected]>
Cc: Jun Piao <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request May 28, 2025
Biju Das <[email protected]> says:

The CAN-FD module on RZ/G3E is very similar to the one on both R-Car V4H
and RZ/G2L, but differs in some hardware parameters:
 * No external clock, but instead has ram clock.
 * Support up to 6 channels.
 * 20 interrupts.

v8->v9:
 * Collected tags.
 * Added missing header bitfield.h.
 * Fixed logical error ch->BIT(ch) in rcar_canfd_global_error().
 * Removed unneeded double space in rcar_canfd_setrnc().
 * Updated commit description in patch#15.
v7->v8:
 * Collected tags.
 * Updated commit description for patch#{5,9,15,16,17}.
 * Replaced the macro RCANFD_GERFL_EEF0_7->RCANFD_GERFL_EEF.
 * Dropped the redundant macro RCANFD_GERFL_EEF(ch).
 * Added patch for dropping the mask operation in RCANFD_GAFLCFG_SETRNC
   macro.
 * Converted RCANFD_GAFLCFG_SETRNC->rcar_canfd_setrnc().
 * Updated RCANFD_GAFLCFG macro by replacing the parameter ch->w, where w
   is the GAFLCFG index used in the hardware manual.
 * Renamed the parameter x->page_num in RCANFD_GAFLECTR_AFLPN macro to
   make it clear.
 * Renamed the parameter x->cftml in RCANFD_CFCC_CFTML macro to make it
   clear.
 * Updated {rzg2l,car_gen3_hw_info} with ch_interface_mode = 0.
 * Updated {rzg2l,rcar_gen3}_hw_info with shared_can_regs = 0.
 * Started using struct rcanfd_regs instead of LUT for reg offsets.
 * Started using struct rcar_canfd_shift_data instead of LUT for shift
   data.
 * Renamed only_internal_clks->external_clk to avoid negation.
 * Updated rcar_canfd_hw_info tables with external_clk entries.
 * Replaced 10->sizeof(name) in scnprintf().
v6->v7:
 * Collected tags
 * Replaced 'aswell'->'as well' in patch#11 commit description.
v5->v6:
 * Replaced RCANFD_RNC_PER_REG macro with rnc_stride variable.
 * Updated commit description for patch#7 and #8
 * Dropped mask_table:
     AFLPN_MASK is replaced by max_aflpn variable.
     CFTML_MASK is replaced by max_cftml variable.
     BITTIMING MASK's are replaced by {nom,data}_bittiming variables.
 * Collected tag from Geert.
v4->v5:
 * Collected tag from Geert.
 * The rules for R-Car Gen3/4 could be kept together, reducing the number
   of lines. Similar change for rzg2l-canfd aswell.
 * Keeping interrupts and resets together allows to keep a clear
   separation between RZ/G2L and RZ/G3E, at the expense of only
   a single line.
 * Retained the tags for binding patches as it is trivial changes.
 * Dropped the unused macro RCANFD_GAFLCFG_GETRNC.
 * Updated macro RCANFD_GERFL_ERR by using gpriv->channels_mask and
   dropped unused macro RCANFD_GERFL_EEF0_7.
 * Replaced RNC mask in RCANFD_GAFLCFG_SETRNC macro by using
   info->num_supported_rules variable.
 * Updated the macro RCANFD_GAFLCFG by using info->rnc_field_width
   variable.
 * Updated shift value in RCANFD_GAFLCFG_SETRNC macro by using a formula
   (32 - (n % rnc_per_reg + 1) * field_width).
 * Replaced the variable name shared_can_reg->shared_can_regs.
 * Improved commit description for patch{#11,#12}by replacing has->have.
 * Dropped RCANFD_EEF_MASK and RCANFD_RNC_MASK as it is taken
   care by gpriv->channels_mask and info->num_supported_rules.
 * Dropped RCANFD_FIRST_RNC_SH and RCANFD_SECOND_RNC_SH by using a
   formula (32 - (n % rnc_per_reg + 1) * rnc_field_width.
 * Improved commit description by "All SoCs supports extenal clock"->
   "All existing SoCs support an external clock".
 * Updated error description in probe as "cannot get enabled ram clock"
 * Updated r9a09g047_hw_info table.
v3->v4:
 * Added Rb tag from Rob for patch#2.
 * Added prefix RCANFD_* to enum rcar_canfd_reg_offset_id.
 * Added prefix RCANFD_* to enum rcar_canfd_mask_id.
 * Added prefix RCANFD_* to enum rcar_canfd_shift_id.
v2->v3:
 * Collected tags.
 * Dropped reg_gen4() and is_gen4() by adding mask_table, shift_table,
   regs, ch_interface_mode and shared_can_reg variables to
   struct rcar_canfd_hw_info.
v1->v2:
 * Split the series with fixes patch separately.
 * Added patch for Simplify rcar_canfd_probe() using
   of_get_available_child_by_name() as dependency patch hit on can-next.
 * Added Rb tag from Vincent Mailhol.
 * Dropped redundant comment from commit description for patch#3.

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
github-actions bot pushed a commit that referenced this pull request Jun 20, 2025
Petr Machata says:

====================
ipmr, ip6mr: Allow MC-routing locally-generated MC packets

Multicast routing is today handled in the input path. Locally generated MC
packets don't hit the IPMR code. Thus if a VXLAN remote address is
multicast, the driver needs to set an OIF during route lookup. In practice
that means that MC routing configuration needs to be kept in sync with the
VXLAN FDB and MDB. Ideally, the VXLAN packets would be routed by the MC
routing code instead.

To that end, this patchset adds support to route locally generated
multicast packets.

However, an installation that uses a VXLAN underlay netdevice for which it
also has matching MC routes, would get a different routing with this patch.
Previously, the MC packets would be delivered directly to the underlay
port, whereas now they would be MC-routed. In order to avoid this change in
behavior, introduce an IPCB/IP6CB flag. Unless the flag is set, the new
MC-routing code is skipped.

All this is keyed to a new VXLAN attribute, IFLA_VXLAN_MC_ROUTE. Only when
it is set does any of the above engage.

In addition to that, and as is the case today with MC forwarding,
IPV4_DEVCONF_MC_FORWARDING must be enabled for the netdevice that acts as a
source of MC traffic (i.e. the VXLAN PHYS_DEV), so an MC daemon must be
attached to the netdevice.

When a VXLAN netdevice with a MC remote is brought up, the physical
netdevice joins the indicated MC group. This is important for local
delivery of MC packets, so it is still necessary to configure a physical
netdevice -- the parameter cannot go away. The netdevice would however
typically not be a front panel port, but a dummy. An MC daemon would then
sit on top of that netdevice as well as any front panel ports that it needs
to service, and have routes set up between the two.

A way to configure the VXLAN netdevice to take advantage of the new MC
routing would be:

 # ip link add name d up type dummy
 # ip link add name vx10 up type vxlan id 1000 dstport 4789 \
	local 192.0.2.1 group 225.0.0.1 ttl 16 dev d mrcoute
 # ip link set dev vx10 master br # plus vlans etc.

With the following MC routes:

 (192.0.2.1, 225.0.0.1) iif=d oil=swp1,swp2 # TX route
 (*, 225.0.0.1) iif=swp1 oil=d,swp2         # RX route
 (*, 225.0.0.1) iif=swp2 oil=d,swp1         # RX route

The RX path has not changed, with the exception of an extra MC hop. Packets
are delivered to the front panel port and MC-forwarded to the VXLAN
physical port, here "d". Since the port has joined the multicast group, the
packets are locally delivered, and end up being processed by the VXLAN
netdevice.

This patchset is based on earlier patches from Nikolay Aleksandrov and
Roopa Prabhu, though it underwent significant changes. Roopa broadly
presented the topic on LPC 2019 [0].

Patchset progression:

- Patches #1 to #4 add ip_mr_output()
- Patches #5 to #10 add ip6_mr_output()
- Patch #11 adds the VXLAN bits to enable MR engagement
- Patches #12 to #14 prepare selftest libraries
- Patch #15 includes a new test suite

[0] https://www.youtube.com/watch?v=xlReECfi-uo
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
github-actions bot pushed a commit that referenced this pull request Jun 26, 2025
Without the change `perf `hangs up on charaster devices. On my system
it's enough to run system-wide sampler for a few seconds to get the
hangup:

    $ perf record -a -g --call-graph=dwarf
    $ perf report
    # hung

`strace` shows that hangup happens on reading on a character device
`/dev/dri/renderD128`

    $ strace -y -f -p 2780484
    strace: Process 2780484 attached
    pread64(101</dev/dri/renderD128>, strace: Process 2780484 detached

It's call trace descends into `elfutils`:

    $ gdb -p 2780484
    (gdb) bt
    #0  0x00007f5e508f04b7 in __libc_pread64 (fd=101, buf=0x7fff9df7edb0, count=0, offset=0)
        at ../sysdeps/unix/sysv/linux/pread64.c:25
    #1  0x00007f5e52b79515 in read_file () from /<<NIX>>/elfutils-0.192/lib/libelf.so.1
    #2  0x00007f5e52b25666 in libdw_open_elf () from /<<NIX>>/elfutils-0.192/lib/libdw.so.1
    #3  0x00007f5e52b25907 in __libdw_open_file () from /<<NIX>>/elfutils-0.192/lib/libdw.so.1
    #4  0x00007f5e52b120a9 in dwfl_report_elf@@ELFUTILS_0.156 ()
       from /<<NIX>>/elfutils-0.192/lib/libdw.so.1
    #5  0x000000000068bf20 in __report_module (al=al@entry=0x7fff9df80010, ip=ip@entry=139803237033216, ui=ui@entry=0x5369b5e0)
        at util/dso.h:537
    #6  0x000000000068c3d1 in report_module (ip=139803237033216, ui=0x5369b5e0) at util/unwind-libdw.c:114
    #7  frame_callback (state=0x535aef10, arg=0x5369b5e0) at util/unwind-libdw.c:242
    #8  0x00007f5e52b261d3 in dwfl_thread_getframes () from /<<NIX>>/elfutils-0.192/lib/libdw.so.1
    #9  0x00007f5e52b25bdb in get_one_thread_cb () from /<<NIX>>/elfutils-0.192/lib/libdw.so.1
    #10 0x00007f5e52b25faa in dwfl_getthreads () from /<<NIX>>/elfutils-0.192/lib/libdw.so.1
    #11 0x00007f5e52b26514 in dwfl_getthread_frames () from /<<NIX>>/elfutils-0.192/lib/libdw.so.1
    #12 0x000000000068c6ce in unwind__get_entries (cb=cb@entry=0x5d4620 <unwind_entry>, arg=arg@entry=0x10cd5fa0,
        thread=thread@entry=0x1076a290, data=data@entry=0x7fff9df80540, max_stack=max_stack@entry=127,
        best_effort=best_effort@entry=false) at util/thread.h:152
    #13 0x00000000005dae95 in thread__resolve_callchain_unwind (evsel=0x106006d0, thread=0x1076a290, cursor=0x10cd5fa0,
        sample=0x7fff9df80540, max_stack=127, symbols=true) at util/machine.c:2939
    #14 thread__resolve_callchain_unwind (thread=0x1076a290, cursor=0x10cd5fa0, evsel=0x106006d0, sample=0x7fff9df80540,
        max_stack=127, symbols=true) at util/machine.c:2920
    #15 __thread__resolve_callchain (thread=0x1076a290, cursor=0x10cd5fa0, evsel=0x106006d0, evsel@entry=0x7fff9df80440,
        sample=0x7fff9df80540, parent=parent@entry=0x7fff9df804a0, root_al=root_al@entry=0x7fff9df80440, max_stack=127, symbols=true)
        at util/machine.c:2970
    #16 0x00000000005d0cb2 in thread__resolve_callchain (thread=<optimized out>, cursor=<optimized out>, evsel=0x7fff9df80440,
        sample=<optimized out>, parent=0x7fff9df804a0, root_al=0x7fff9df80440, max_stack=127) at util/machine.h:198
    #17 sample__resolve_callchain (sample=<optimized out>, cursor=<optimized out>, parent=parent@entry=0x7fff9df804a0,
        evsel=evsel@entry=0x106006d0, al=al@entry=0x7fff9df80440, max_stack=max_stack@entry=127) at util/callchain.c:1127
    #18 0x0000000000617e08 in hist_entry_iter__add (iter=iter@entry=0x7fff9df80480, al=al@entry=0x7fff9df80440, max_stack_depth=127,
        arg=arg@entry=0x7fff9df81ae0) at util/hist.c:1255
    #19 0x000000000045d2d0 in process_sample_event (tool=0x7fff9df81ae0, event=<optimized out>, sample=0x7fff9df80540,
        evsel=0x106006d0, machine=<optimized out>) at builtin-report.c:334
    #20 0x00000000005e3bb1 in perf_session__deliver_event (session=0x105ff2c0, event=0x7f5c7d735ca0, tool=0x7fff9df81ae0,
        file_offset=2914716832, file_path=0x105ffbf0 "perf.data") at util/session.c:1367
    #21 0x00000000005e8d93 in do_flush (oe=0x105ffa50, show_progress=false) at util/ordered-events.c:245
    #22 __ordered_events__flush (oe=0x105ffa50, how=OE_FLUSH__ROUND, timestamp=<optimized out>) at util/ordered-events.c:324
    #23 0x00000000005e1f64 in perf_session__process_user_event (session=0x105ff2c0, event=0x7f5c7d752b18, file_offset=2914835224,
        file_path=0x105ffbf0 "perf.data") at util/session.c:1419
    #24 0x00000000005e47c7 in reader__read_event (rd=rd@entry=0x7fff9df81260, session=session@entry=0x105ff2c0,
    --Type <RET> for more, q to quit, c to continue without paging--
    quit
        prog=prog@entry=0x7fff9df81220) at util/session.c:2132
    #25 0x00000000005e4b37 in reader__process_events (rd=0x7fff9df81260, session=0x105ff2c0, prog=0x7fff9df81220)
        at util/session.c:2181
    #26 __perf_session__process_events (session=0x105ff2c0) at util/session.c:2226
    #27 perf_session__process_events (session=session@entry=0x105ff2c0) at util/session.c:2390
    #28 0x0000000000460add in __cmd_report (rep=0x7fff9df81ae0) at builtin-report.c:1076
    #29 cmd_report (argc=<optimized out>, argv=<optimized out>) at builtin-report.c:1827
    #30 0x00000000004c5a40 in run_builtin (p=p@entry=0xd8f7f8 <commands+312>, argc=argc@entry=1, argv=argv@entry=0x7fff9df844b0)
        at perf.c:351
    #31 0x00000000004c5d63 in handle_internal_command (argc=argc@entry=1, argv=argv@entry=0x7fff9df844b0) at perf.c:404
    #32 0x0000000000442de3 in run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:448
    #33 main (argc=<optimized out>, argv=0x7fff9df844b0) at perf.c:556

The hangup happens because nothing in` perf` or `elfutils` checks if a
mapped file is easily readable.

The change conservatively skips all non-regular files.

Signed-off-by: Sergei Trofimovich <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Jun 27, 2025
Symbolize stack traces by creating a live machine. Add this
functionality to dump_stack and switch dump_stack users to use
it. Switch TUI to use it. Add stack traces to the child test function
which can be useful to diagnose blocked code.

Example output:
```
$ perf test -vv PERF_RECORD_
...
  7: PERF_RECORD_* events & perf_sample fields:
  7: PERF_RECORD_* events & perf_sample fields                       : Running (1 active)
^C
Signal (2) while running tests.
Terminating tests with the same signal
Internal test harness failure. Completing any started tests:
:  7: PERF_RECORD_* events & perf_sample fields:

---- unexpected signal (2) ----
    #0 0x55788c6210a3 in child_test_sig_handler builtin-test.c:0
    #1 0x7fc12fe49df0 in __restore_rt libc_sigaction.c:0
    #2 0x7fc12fe99687 in __internal_syscall_cancel cancellation.c:64
    #3 0x7fc12fee5f7a in clock_nanosleep@GLIBC_2.2.5 clock_nanosleep.c:72
    #4 0x7fc12fef1393 in __nanosleep nanosleep.c:26
    #5 0x7fc12ff02d68 in __sleep sleep.c:55
    #6 0x55788c63196b in test__PERF_RECORD perf-record.c:0
    #7 0x55788c620fb0 in run_test_child builtin-test.c:0
    #8 0x55788c5bd18d in start_command run-command.c:127
    #9 0x55788c621ef3 in __cmd_test builtin-test.c:0
    #10 0x55788c6225bf in cmd_test ??:0
    #11 0x55788c5afbd0 in run_builtin perf.c:0
    #12 0x55788c5afeeb in handle_internal_command perf.c:0
    #13 0x55788c52b383 in main ??:0
    #14 0x7fc12fe33ca8 in __libc_start_call_main libc_start_call_main.h:74
    #15 0x7fc12fe33d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    #16 0x55788c52b9d1 in _start ??:0

---- unexpected signal (2) ----
    #0 0x55788c6210a3 in child_test_sig_handler builtin-test.c:0
    #1 0x7fc12fe49df0 in __restore_rt libc_sigaction.c:0
    #2 0x7fc12fea3a14 in pthread_sigmask@GLIBC_2.2.5 pthread_sigmask.c:45
    #3 0x7fc12fe49fd9 in __GI___sigprocmask sigprocmask.c:26
    #4 0x7fc12ff2601b in __longjmp_chk longjmp.c:36
    #5 0x55788c6210c0 in print_test_result.isra.0 builtin-test.c:0
    #6 0x7fc12fe49df0 in __restore_rt libc_sigaction.c:0
    #7 0x7fc12fe99687 in __internal_syscall_cancel cancellation.c:64
    #8 0x7fc12fee5f7a in clock_nanosleep@GLIBC_2.2.5 clock_nanosleep.c:72
    #9 0x7fc12fef1393 in __nanosleep nanosleep.c:26
    #10 0x7fc12ff02d68 in __sleep sleep.c:55
    #11 0x55788c63196b in test__PERF_RECORD perf-record.c:0
    #12 0x55788c620fb0 in run_test_child builtin-test.c:0
    #13 0x55788c5bd18d in start_command run-command.c:127
    #14 0x55788c621ef3 in __cmd_test builtin-test.c:0
    #15 0x55788c6225bf in cmd_test ??:0
    #16 0x55788c5afbd0 in run_builtin perf.c:0
    #17 0x55788c5afeeb in handle_internal_command perf.c:0
    #18 0x55788c52b383 in main ??:0
    #19 0x7fc12fe33ca8 in __libc_start_call_main libc_start_call_main.h:74
    #20 0x7fc12fe33d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    #21 0x55788c52b9d1 in _start ??:0
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Signed-off-by: Ian Rogers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Jul 1, 2025
Calling perf top with branch filters enabled on Intel CPU's
with branch counters logging (A.K.A LBR event logging [1]) support
results in a segfault.

$ perf top  -e '{cpu_core/cpu-cycles/,cpu_core/event=0xc6,umask=0x3,frontend=0x11,name=frontend_retired_dsb_miss/}' -j any,counter
...
Thread 27 "perf" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffafff76c0 (LWP 949003)]
perf_env__find_br_cntr_info (env=0xf66dc0 <perf_env>, nr=0x0, width=0x7fffafff62c0) at util/env.c:653
653			*width = env->cpu_pmu_caps ? env->br_cntr_width :
(gdb) bt
 #0  perf_env__find_br_cntr_info (env=0xf66dc0 <perf_env>, nr=0x0, width=0x7fffafff62c0) at util/env.c:653
 #1  0x00000000005b1599 in symbol__account_br_cntr (branch=0x7fffcc3db580, evsel=0xfea2d0, offset=12, br_cntr=8) at util/annotate.c:345
 #2  0x00000000005b17fb in symbol__account_cycles (addr=5658172, start=5658160, sym=0x7fffcc0ee420, cycles=539, evsel=0xfea2d0, br_cntr=8) at util/annotate.c:389
 #3  0x00000000005b1976 in addr_map_symbol__account_cycles (ams=0x7fffcd7b01d0, start=0x7fffcd7b02b0, cycles=539, evsel=0xfea2d0, br_cntr=8) at util/annotate.c:422
 #4  0x000000000068d57f in hist__account_cycles (bs=0x110d288, al=0x7fffafff6540, sample=0x7fffafff6760, nonany_branch_mode=false, total_cycles=0x0, evsel=0xfea2d0) at util/hist.c:2850
 #5  0x0000000000446216 in hist_iter__top_callback (iter=0x7fffafff6590, al=0x7fffafff6540, single=true, arg=0x7fffffff9e00) at builtin-top.c:737
 #6  0x0000000000689787 in hist_entry_iter__add (iter=0x7fffafff6590, al=0x7fffafff6540, max_stack_depth=127, arg=0x7fffffff9e00) at util/hist.c:1359
 #7  0x0000000000446710 in perf_event__process_sample (tool=0x7fffffff9e00, event=0x110d250, evsel=0xfea2d0, sample=0x7fffafff6760, machine=0x108c968) at builtin-top.c:845
 #8  0x0000000000447735 in deliver_event (qe=0x7fffffffa120, qevent=0x10fc200) at builtin-top.c:1211
 #9  0x000000000064ccae in do_flush (oe=0x7fffffffa120, show_progress=false) at util/ordered-events.c:245
 #10 0x000000000064d005 in __ordered_events__flush (oe=0x7fffffffa120, how=OE_FLUSH__TOP, timestamp=0) at util/ordered-events.c:324
 #11 0x000000000064d0ef in ordered_events__flush (oe=0x7fffffffa120, how=OE_FLUSH__TOP) at util/ordered-events.c:342
 #12 0x00000000004472a9 in process_thread (arg=0x7fffffff9e00) at builtin-top.c:1120
 #13 0x00007ffff6e7dba8 in start_thread (arg=<optimized out>) at pthread_create.c:448
 #14 0x00007ffff6f01b8c in __GI___clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

The cause is that perf_env__find_br_cntr_info tries to access a
null pointer pmu_caps in the perf_env struct. A similar issue exists
for homogeneous core systems which use the cpu_pmu_caps structure.

Fix this by populating cpu_pmu_caps and pmu_caps structures with
values from sysfs when calling perf top with branch stack sampling
enabled.

[1], LBR event logging introduced here:
https://lore.kernel.org/all/[email protected]/

Reviewed-by: Ian Rogers <[email protected]>
Signed-off-by: Thomas Falcon <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Jul 5, 2025
In probe appletb_kbd_probe() a "struct appletb_kbd *kbd" is allocated
via devm_kzalloc() to store touch bar keyboard related data.
Later on if backlight_device_get_by_name() finds a backlight device
with name "appletb_backlight" a timer (kbd->inactivity_timer) is setup
with appletb_inactivity_timer() and the timer is armed to run after
appletb_tb_dim_timeout (60) seconds.

A use-after-free is triggered when failure occurs after the timer is
armed. This ultimately means probe failure occurs and as a result the
"struct appletb_kbd *kbd" which is device managed memory is freed.
After 60 seconds the timer will have expired and __run_timers will
attempt to access the timer (kbd->inactivity_timer) however the kdb
structure has been freed causing a use-after free.

[   71.636938] ==================================================================
[   71.637915] BUG: KASAN: slab-use-after-free in __run_timers+0x7ad/0x890
[   71.637915] Write of size 8 at addr ffff8881178c5958 by task swapper/1/0
[   71.637915]
[   71.637915] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.16.0-rc2-00318-g739a6c93cc75-dirty #12 PREEMPT(voluntary)
[   71.637915] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[   71.637915] Call Trace:
[   71.637915]  <IRQ>
[   71.637915]  dump_stack_lvl+0x53/0x70
[   71.637915]  print_report+0xce/0x670
[   71.637915]  ? __run_timers+0x7ad/0x890
[   71.637915]  kasan_report+0xce/0x100
[   71.637915]  ? __run_timers+0x7ad/0x890
[   71.637915]  __run_timers+0x7ad/0x890
[   71.637915]  ? __pfx___run_timers+0x10/0x10
[   71.637915]  ? update_process_times+0xfc/0x190
[   71.637915]  ? __pfx_update_process_times+0x10/0x10
[   71.637915]  ? _raw_spin_lock_irq+0x80/0xe0
[   71.637915]  ? _raw_spin_lock_irq+0x80/0xe0
[   71.637915]  ? __pfx__raw_spin_lock_irq+0x10/0x10
[   71.637915]  run_timer_softirq+0x141/0x240
[   71.637915]  ? __pfx_run_timer_softirq+0x10/0x10
[   71.637915]  ? __pfx___hrtimer_run_queues+0x10/0x10
[   71.637915]  ? kvm_clock_get_cycles+0x18/0x30
[   71.637915]  ? ktime_get+0x60/0x140
[   71.637915]  handle_softirqs+0x1b8/0x5c0
[   71.637915]  ? __pfx_handle_softirqs+0x10/0x10
[   71.637915]  irq_exit_rcu+0xaf/0xe0
[   71.637915]  sysvec_apic_timer_interrupt+0x6c/0x80
[   71.637915]  </IRQ>
[   71.637915]
[   71.637915] Allocated by task 39:
[   71.637915]  kasan_save_stack+0x33/0x60
[   71.637915]  kasan_save_track+0x14/0x30
[   71.637915]  __kasan_kmalloc+0x8f/0xa0
[   71.637915]  __kmalloc_node_track_caller_noprof+0x195/0x420
[   71.637915]  devm_kmalloc+0x74/0x1e0
[   71.637915]  appletb_kbd_probe+0x37/0x3c0
[   71.637915]  hid_device_probe+0x2d1/0x680
[   71.637915]  really_probe+0x1c3/0x690
[   71.637915]  __driver_probe_device+0x247/0x300
[   71.637915]  driver_probe_device+0x49/0x210
[...]
[   71.637915]
[   71.637915] Freed by task 39:
[   71.637915]  kasan_save_stack+0x33/0x60
[   71.637915]  kasan_save_track+0x14/0x30
[   71.637915]  kasan_save_free_info+0x3b/0x60
[   71.637915]  __kasan_slab_free+0x37/0x50
[   71.637915]  kfree+0xcf/0x360
[   71.637915]  devres_release_group+0x1f8/0x3c0
[   71.637915]  hid_device_probe+0x315/0x680
[   71.637915]  really_probe+0x1c3/0x690
[   71.637915]  __driver_probe_device+0x247/0x300
[   71.637915]  driver_probe_device+0x49/0x210
[...]

The root cause of the issue is that the timer is not disarmed
on failure paths leading to it remaining active and accessing
freed memory. To fix this call timer_delete_sync() to deactivate
the timer.

Another small issue is that timer_delete_sync is called
unconditionally in appletb_kbd_remove(), fix this by checking
for a valid kbd->backlight_dev before calling timer_delete_sync.

Fixes: 93a0fc4 ("HID: hid-appletb-kbd: add support for automatic brightness control while using the touchbar")
Cc: [email protected]
Signed-off-by: Qasim Ijaz <[email protected]>
Reviewed-by: Aditya Garg <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
nunojsa pushed a commit that referenced this pull request Aug 5, 2025
commit 54ec8b0 upstream.

echo_skb_max should define the supported upper limit of echo_skb[]
allocated inside the netdevice's priv. The corresponding size value
provided by this driver to alloc_candev() is KVASER_PCIEFD_CAN_TX_MAX_COUNT
which is 17.

But later echo_skb_max is rounded up to the nearest power of two (for the
max case, that would be 32) and the tx/ack indices calculated further
during tx/rx may exceed the upper array boundary. Kasan reported this for
the ack case inside kvaser_pciefd_handle_ack_packet(), though the xmit
function has actually caught the same thing earlier.

 BUG: KASAN: slab-out-of-bounds in kvaser_pciefd_handle_ack_packet+0x2d7/0x92a drivers/net/can/kvaser_pciefd.c:1528
 Read of size 8 at addr ffff888105e4f078 by task swapper/4/0

 CPU: 4 UID: 0 PID: 0 Comm: swapper/4 Not tainted 6.15.0 #12 PREEMPT(voluntary)
 Call Trace:
  <IRQ>
 dump_stack_lvl lib/dump_stack.c:122
 print_report mm/kasan/report.c:521
 kasan_report mm/kasan/report.c:634
 kvaser_pciefd_handle_ack_packet drivers/net/can/kvaser_pciefd.c:1528
 kvaser_pciefd_read_packet drivers/net/can/kvaser_pciefd.c:1605
 kvaser_pciefd_read_buffer drivers/net/can/kvaser_pciefd.c:1656
 kvaser_pciefd_receive_irq drivers/net/can/kvaser_pciefd.c:1684
 kvaser_pciefd_irq_handler drivers/net/can/kvaser_pciefd.c:1733
 __handle_irq_event_percpu kernel/irq/handle.c:158
 handle_irq_event kernel/irq/handle.c:210
 handle_edge_irq kernel/irq/chip.c:833
 __common_interrupt arch/x86/kernel/irq.c:296
 common_interrupt arch/x86/kernel/irq.c:286
  </IRQ>

Tx max count definitely matters for kvaser_pciefd_tx_avail(), but for seq
numbers' generation that's not the case - we're free to calculate them as
would be more convenient, not taking tx max count into account. The only
downside is that the size of echo_skb[] should correspond to the max seq
number (not tx max count), so in some situations a bit more memory would
be consumed than could be.

Thus make the size of the underlying echo_skb[] sufficient for the rounded
max tx value.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 8256e0c ("can: kvaser_pciefd: Fix echo_skb race")
Cc: [email protected]
Signed-off-by: Fedor Pchelkin <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nunojsa pushed a commit that referenced this pull request Aug 5, 2025
[ Upstream commit eedf3e3 ]

ACPICA commit 1c28da2242783579d59767617121035dafba18c3

This was originally done in NetBSD:
NetBSD/src@b69d1ac
and is the correct alternative to the smattering of `memcpy`s I
previously contributed to this repository.

This also sidesteps the newly strict checks added in UBSAN:
llvm/llvm-project@7926744

Before this change we see the following UBSAN stack trace in Fuchsia:

  #0    0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e
  #1.2  0x000021982bc4af3c in ubsan_get_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:41 <libclang_rt.asan.so>+0x41f3c
  #1.1  0x000021982bc4af3c in maybe_print_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:51 <libclang_rt.asan.so>+0x41f3c
  #1    0x000021982bc4af3c in ~scoped_report() compiler-rt/lib/ubsan/ubsan_diag.cpp:395 <libclang_rt.asan.so>+0x41f3c
  #2    0x000021982bc4bb6f in handletype_mismatch_impl() compiler-rt/lib/ubsan/ubsan_handlers.cpp:137 <libclang_rt.asan.so>+0x42b6f
  #3    0x000021982bc4b723 in __ubsan_handle_type_mismatch_v1 compiler-rt/lib/ubsan/ubsan_handlers.cpp:142 <libclang_rt.asan.so>+0x42723
  #4    0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e
  #5    0x000021afcfdf2089 in acpi_rs_convert_aml_to_resource(struct acpi_resource*, union aml_resource*, struct acpi_rsconvert_info*) ../../third_party/acpica/source/components/resources/rsmisc.c:355 <platform-bus-x86.so>+0x6b2089
  #6    0x000021afcfded169 in acpi_rs_convert_aml_to_resources(u8*, u32, u32, u8, void**) ../../third_party/acpica/source/components/resources/rslist.c:137 <platform-bus-x86.so>+0x6ad169
  #7    0x000021afcfe2d24a in acpi_ut_walk_aml_resources(struct acpi_walk_state*, u8*, acpi_size, acpi_walk_aml_callback, void**) ../../third_party/acpica/source/components/utilities/utresrc.c:237 <platform-bus-x86.so>+0x6ed24a
  #8    0x000021afcfde66b7 in acpi_rs_create_resource_list(union acpi_operand_object*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rscreate.c:199 <platform-bus-x86.so>+0x6a66b7
  #9    0x000021afcfdf6979 in acpi_rs_get_method_data(acpi_handle, const char*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rsutils.c:770 <platform-bus-x86.so>+0x6b6979
  #10   0x000021afcfdf708f in acpi_walk_resources(acpi_handle, char*, acpi_walk_resource_callback, void*) ../../third_party/acpica/source/components/resources/rsxface.c:731 <platform-bus-x86.so>+0x6b708f
  #11   0x000021afcfa95dcf in acpi::acpi_impl::walk_resources(acpi::acpi_impl*, acpi_handle, const char*, acpi::Acpi::resources_callable) ../../src/devices/board/lib/acpi/acpi-impl.cc:41 <platform-bus-x86.so>+0x355dcf
  #12   0x000021afcfaa8278 in acpi::device_builder::gather_resources(acpi::device_builder*, acpi::Acpi*, fidl::any_arena&, acpi::Manager*, acpi::device_builder::gather_resources_callback) ../../src/devices/board/lib/acpi/device-builder.cc:84 <platform-bus-x86.so>+0x368278
  #13   0x000021afcfbddb87 in acpi::Manager::configure_discovered_devices(acpi::Manager*) ../../src/devices/board/lib/acpi/manager.cc:75 <platform-bus-x86.so>+0x49db87
  #14   0x000021afcf99091d in publish_acpi_devices(acpi::Manager*, zx_device_t*, zx_device_t*) ../../src/devices/board/drivers/x86/acpi-nswalk.cc:95 <platform-bus-x86.so>+0x25091d
  #15   0x000021afcf9c1d4e in x86::X86::do_init(x86::X86*) ../../src/devices/board/drivers/x86/x86.cc:60 <platform-bus-x86.so>+0x281d4e
  #16   0x000021afcf9e33ad in λ(x86::X86::ddk_init::(anon class)*) ../../src/devices/board/drivers/x86/x86.cc:77 <platform-bus-x86.so>+0x2a33ad
  #17   0x000021afcf9e313e in fit::internal::target<(lambda at../../src/devices/board/drivers/x86/x86.cc:76:19), false, false, std::__2::allocator<std::byte>, void>::invoke(void*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:183 <platform-bus-x86.so>+0x2a313e
  #18   0x000021afcfbab4c7 in fit::internal::function_base<16UL, false, void(), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <platform-bus-x86.so>+0x46b4c7
  #19   0x000021afcfbab342 in fit::function_impl<16UL, false, void(), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/function.h:315 <platform-bus-x86.so>+0x46b342
  #20   0x000021afcfcd98c3 in async::internal::retained_task::Handler(async_dispatcher_t*, async_task_t*, zx_status_t) ../../sdk/lib/async/task.cc:24 <platform-bus-x86.so>+0x5998c3
  #21   0x00002290f9924616 in λ(const driver_runtime::Dispatcher::post_task::(anon class)*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/dispatcher.cc:789 <libdriver_runtime.so>+0x10a616
  #22   0x00002290f9924323 in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:788:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int>::invoke(void*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0x10a323
  #23   0x00002290f9904b76 in fit::internal::function_base<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xeab76
  #24   0x00002290f9904831 in fit::callback_impl<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::operator()(fit::callback_impl<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/function.h:471 <libdriver_runtime.so>+0xea831
  #25   0x00002290f98d5adc in driver_runtime::callback_request::Call(driver_runtime::callback_request*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/callback_request.h:74 <libdriver_runtime.so>+0xbbadc
  #26   0x00002290f98e1e58 in driver_runtime::Dispatcher::dispatch_callback(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >) ../../src/devices/bin/driver_runtime/dispatcher.cc:1248 <libdriver_runtime.so>+0xc7e58
  #27   0x00002290f98e4159 in driver_runtime::Dispatcher::dispatch_callbacks(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:1308 <libdriver_runtime.so>+0xca159
  #28   0x00002290f9918414 in λ(const driver_runtime::Dispatcher::create_with_adder::(anon class)*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:353 <libdriver_runtime.so>+0xfe414
  #29   0x00002290f991812d in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:351:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>>::invoke(void*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0xfe12d
  #30   0x00002290f9906fc7 in fit::internal::function_base<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xecfc7
  #31   0x00002290f9906c66 in fit::function_impl<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/function.h:315 <libdriver_runtime.so>+0xecc66
  #32   0x00002290f98e73d9 in driver_runtime::Dispatcher::event_waiter::invoke_callback(driver_runtime::Dispatcher::event_waiter*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.h:543 <libdriver_runtime.so>+0xcd3d9
  #33   0x00002290f98e700d in driver_runtime::Dispatcher::event_waiter::handle_event(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/dispatcher.cc:1442 <libdriver_runtime.so>+0xcd00d
  #34   0x00002290f9918983 in async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event(async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>*, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/async_loop_owned_event_handler.h:59 <libdriver_runtime.so>+0xfe983
  #35   0x00002290f9918b9e in async::wait_method<async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>, &async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event>::call_handler(async_dispatcher_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async/include/lib/async/cpp/wait.h:201 <libdriver_runtime.so>+0xfeb9e
  #36   0x00002290f99bf509 in async_loop_dispatch_wait(async_loop_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async-loop/loop.c:394 <libdriver_runtime.so>+0x1a5509
  #37   0x00002290f99b9958 in async_loop_run_once(async_loop_t*, zx_time_t) ../../sdk/lib/async-loop/loop.c:343 <libdriver_runtime.so>+0x19f958
  #38   0x00002290f99b9247 in async_loop_run(async_loop_t*, zx_time_t, _Bool) ../../sdk/lib/async-loop/loop.c:301 <libdriver_runtime.so>+0x19f247
  #39   0x00002290f99ba962 in async_loop_run_thread(void*) ../../sdk/lib/async-loop/loop.c:860 <libdriver_runtime.so>+0x1a0962
  #40   0x000041afd176ef30 in start_c11(void*) ../../zircon/third_party/ulib/musl/pthread/pthread_create.c:63 <libc.so>+0x84f30
  #41   0x000041afd18a448d in thread_trampoline(uintptr_t, uintptr_t) ../../zircon/system/ulib/runtime/thread.cc:100 <libc.so>+0x1ba48d

Link: acpica/acpica@1c28da22
Signed-off-by: Rafael J. Wysocki <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Tamir Duberstein <[email protected]>
[ rjw: Pick up the tag from Tamir ]
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
github-actions bot pushed a commit that referenced this pull request Aug 23, 2025
Receiving HSR frame with insufficient space to hold HSR tag in the skb
can result in a crash (kernel BUG):

[   45.390915] skbuff: skb_under_panic: text:ffffffff86f32cac len:26 put:14 head:ffff888042418000 data:ffff888042417ff4 tail:0xe end:0x180 dev:bridge_slave_1
[   45.392559] ------------[ cut here ]------------
[   45.392912] kernel BUG at net/core/skbuff.c:211!
[   45.393276] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[   45.393809] CPU: 1 UID: 0 PID: 2496 Comm: reproducer Not tainted 6.15.0 #12 PREEMPT(undef)
[   45.394433] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   45.395273] RIP: 0010:skb_panic+0x15b/0x1d0

<snip registers, remove unreliable trace>

[   45.402911] Call Trace:
[   45.403105]  <IRQ>
[   45.404470]  skb_push+0xcd/0xf0
[   45.404726]  br_dev_queue_push_xmit+0x7c/0x6c0
[   45.406513]  br_forward_finish+0x128/0x260
[   45.408483]  __br_forward+0x42d/0x590
[   45.409464]  maybe_deliver+0x2eb/0x420
[   45.409763]  br_flood+0x174/0x4a0
[   45.410030]  br_handle_frame_finish+0xc7c/0x1bc0
[   45.411618]  br_handle_frame+0xac3/0x1230
[   45.413674]  __netif_receive_skb_core.constprop.0+0x808/0x3df0
[   45.422966]  __netif_receive_skb_one_core+0xb4/0x1f0
[   45.424478]  __netif_receive_skb+0x22/0x170
[   45.424806]  process_backlog+0x242/0x6d0
[   45.425116]  __napi_poll+0xbb/0x630
[   45.425394]  net_rx_action+0x4d1/0xcc0
[   45.427613]  handle_softirqs+0x1a4/0x580
[   45.427926]  do_softirq+0x74/0x90
[   45.428196]  </IRQ>

This issue was found by syzkaller.

The panic happens in br_dev_queue_push_xmit() once it receives a
corrupted skb with ETH header already pushed in linear data. When it
attempts the skb_push() call, there's not enough headroom and
skb_push() panics.

The corrupted skb is put on the queue by HSR layer, which makes a
sequence of unintended transformations when it receives a specific
corrupted HSR frame (with incomplete TAG).

Fix it by dropping and consuming frames that are not long enough to
contain both ethernet and hsr headers.

Alternative fix would be to check for enough headroom before skb_push()
in br_dev_queue_push_xmit().

In the reproducer, this is injected via AF_PACKET, but I don't easily
see why it couldn't be sent over the wire from adjacent network.

Further Details:

In the reproducer, the following network interface chain is set up:

┌────────────────┐   ┌────────────────┐
│ veth0_to_hsr   ├───┤  hsr_slave0    ┼───┐
└────────────────┘   └────────────────┘   │
                                          │ ┌──────┐
                                          ├─┤ hsr0 ├───┐
                                          │ └──────┘   │
┌────────────────┐   ┌────────────────┐   │            │┌────────┐
│ veth1_to_hsr   ┼───┤  hsr_slave1    ├───┘            └┤        │
└────────────────┘   └────────────────┘                ┌┼ bridge │
                                                       ││        │
                                                       │└────────┘
                                                       │
                                        ┌───────┐      │
                                        │  ...  ├──────┘
                                        └───────┘

To trigger the events leading up to crash, reproducer sends a corrupted
HSR frame with incomplete TAG, via AF_PACKET socket on 'veth0_to_hsr'.

The first HSR-layer function to process this frame is
hsr_handle_frame(). It and then checks if the
protocol is ETH_P_PRP or ETH_P_HSR. If it is, it calls
skb_set_network_header(skb, ETH_HLEN + HSR_HLEN), without checking that
the skb is long enough. For the crashing frame it is not, and hence the
skb->network_header and skb->mac_len fields are set incorrectly,
pointing after the end of the linear buffer.

I will call this a BUG#1 and it is what is addressed by this patch. In
the crashing scenario before the fix, the skb continues to go down the
hsr path as follows.

hsr_handle_frame() then calls this sequence
hsr_forward_skb()
  fill_frame_info()
    hsr->proto_ops->fill_frame_info()
      hsr_fill_frame_info()

hsr_fill_frame_info() contains a check that intends to check whether the
skb actually contains the HSR header. But the check relies on the
skb->mac_len field which was erroneously setup due to BUG#1, so the
check passes and the execution continues  back in the hsr_forward_skb():

hsr_forward_skb()
  hsr_forward_do()
    hsr->proto_ops->get_untagged_frame()
      hsr_get_untagged_frame()
        create_stripped_skb_hsr()

In create_stripped_skb_hsr(), a copy of the skb is created and is
further corrupted by operation that attempts to strip the HSR tag in a
call to __pskb_copy().

The skb enters create_stripped_skb_hsr() with ethernet header pushed in
linear buffer. The skb_pull(skb_in, HSR_HLEN) thus pulls 6 bytes of
ethernet header into the headroom, creating skb_in with a headroom of
size 8. The subsequent __pskb_copy() then creates an skb with headroom
of just 2 and skb->len of just 12, this is how it looks after the copy:

gdb) p skb->len
$10 = 12
(gdb) p skb->data
$11 = (unsigned char *) 0xffff888041e45382 "\252\252\252\252\252!\210\373",
(gdb) p skb->head
$12 = (unsigned char *) 0xffff888041e45380 ""

It seems create_stripped_skb_hsr() assumes that ETH header is pulled
in the headroom when it's entered, because it just pulls HSR header on
top. But that is not the case in our code-path and we end up with the
corrupted skb instead. I will call this BUG#2

*I got confused here because it seems that under no conditions can
create_stripped_skb_hsr() work well, the assumption it makes is not true
during the processing of hsr frames - since the skb_push() in
hsr_handle_frame to skb_pull in hsr_deliver_master(). I wonder whether I
missed something here.*

Next, the execution arrives in hsr_deliver_master(). It calls
skb_pull(ETH_HLEN), which just returns NULL - the SKB does not have
enough space for the pull (as it only has 12 bytes in total at this
point).

*The skb_pull() here further suggests that ethernet header is meant
to be pushed through the whole hsr processing and
create_stripped_skb_hsr() should pull it before doing the HSR header
pull.*

hsr_deliver_master() then puts the corrupted skb on the queue, it is
then picked up from there by bridge frame handling layer and finally
lands in br_dev_queue_push_xmit where it panics.

Cc: [email protected]
Fixes: 48b491a ("net: hsr: fix mac_len checks")
Reported-by: [email protected]
Signed-off-by: Jakub Acs <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 30, 2025
…CAN XL step 3/3"

Vincent Mailhol <[email protected]> says:

In November last year, I sent an RFC to introduce CAN XL [1]. That
RFC, despite positive feedback, was put on hold due to some unanswered
question concerning the PWM encoding [2].

While stuck, some small preparation work was done in parallel in [3]
by refactoring the struct can_priv and doing some trivial clean-up and
renaming. Initially, [3] received zero feedback but was eventually
merged after splitting it in smaller parts and resending it.

Finally, in July this year, we clarified the remaining mysteries about
PWM calculation, thus unlocking the series. Summer being a bit busy
because of some personal matters brings us to now.

After doing all the refactoring and adding all the CAN XL features,
the final result is more than 30 patches, definitively too much for a
single series. So I am splitting the remaining changes three:

  - can: rework the CAN MTU logic [4]
  - can: netlink: preparation before introduction of CAN XL (this series)
  - CAN XL (will come right after the two preparation series get merged)

And thus, this series continues and finishes the preparation work done
in [3] and [4]. It contains all the refactoring needed to smoothly
introduce CAN XL. The goal is to:

  - split the functions in smaller pieces: CAN XL will introduce a
    fair amount of code. And some functions which are already fairly
    long (86 lines for can_validate(), 215 lines for can_changelink())
    would grow to disproportionate sizes if the CAN XL logic were to
    be inlined in those functions.

  - repurpose the existing code to handle both CAN FD and CAN XL: a
    huge part of CAN XL simply reuses the CAN FD logic. All the
    existing CAN FD logic is made more generic to handle both CAN FD
    and XL.

In more details:

  - Patch #1 moves struct data_bittiming_params from dev.h to
    bittiming.h and patch #2 makes can_get_relative_tdco() FD agnostic
    before also moving it to bittiming.h.

  - Patch #3 adds some comments to netlink.h tagging which IFLA
    symbols are FD specific.

  - Patches #4 to #6 are refactoring can_validate() and
    can_validate_bittiming().

  - Patches #7 to #11 are refactoring can_changelink() and
    can_tdc_changelink().

  - Patches #12 and #13 are refactoring can_get_size() and
    can_tdc_get_size().

  - Patches #14 to #17 are refactoring can_fill_info() and
    can_tdc_fill_info().

  - Patch #18 makes can_calc_tdco() FD agnostic.

  - Patch #19 adds can_get_ctrlmode_str() which converts control mode
    flags into strings. This is done in preparation of patch #20.

  - Patch #20 is the final patch and improves the user experience by
    providing detailed error messages whenever invalid parameters are
    provided. All those error messages came into handy when debugging
    the upcoming CAN XL patches.

Aside from the last patch, the other changes do not impact any of the
existing functionalities.

The follow up series which introduces CAN XL is nearly completed but
will be sent only once this one is approved: one thing at a time, I do
not want to overwhelm people (including myself).

[1] https://lore.kernel.org/linux-can/[email protected]/
[2] https://lore.kernel.org/linux-can/[email protected]/
[3] https://lore.kernel.org/linux-can/[email protected]/
[4] https://lore.kernel.org/linux-can/[email protected]/

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 30, 2025
Petr Machata says:

====================
selftests: Mark auto-deferring functions clearly

selftests/net/lib.sh contains a suite of iproute2 wrappers that
automatically schedule the corresponding cleanup through defer. The fact
they do so is however not immediately obvious, one needs to know which
functions are handling the deferral behind the scenes, and which expect the
caller to handle cleanups themselves.

A convention for these auto-deferring functions would help both writing and
patch review. This patchset does so by marking these functions with an adf_
prefix. We already have a few such functions: forwarding/lib.sh has
adf_mcd_start() and a few selftests add private helpers that conform to
this convention.

Patches #1 to #8 gradually convert individual functions, one per patch.

Patch #9 renames an auto-deferring private helpers named dfr_* to adf_*.
The plan is not to retro-rename all private helpers, but I happened to know
about this one.

Patches #10 to #12 introduce several autodefer helpers for commonly used
forwarding/lib.sh functions, and opportunistically convert straightforward
instances of 'action; defer counteraction' to the new helpers.

Patch #13 adds some README verbiage to pitch defer and the adf_*
convention.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
github-actions bot pushed a commit that referenced this pull request Oct 10, 2025
The test starts a workload and then opens events. If the events fail
to open, for example because of perf_event_paranoid, the gopipe of the
workload is leaked and the file descriptor leak check fails when the
test exits. To avoid this cancel the workload when opening the events
fails.

Before:
```
$ perf test -vv 7
  7: PERF_RECORD_* events & perf_sample fields:
 --- start ---
test child forked, pid 1189568
Using CPUID GenuineIntel-6-B7-1
 ------------------------------------------------------------
perf_event_attr:
  type                    	   0 (PERF_TYPE_HARDWARE)
  config                  	   0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                	   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
Attempt to add: software/cpu-clock/
..after resolving event: software/config=0/
cpu-clock -> software/cpu-clock/
 ------------------------------------------------------------
perf_event_attr:
  type                             1 (PERF_TYPE_SOFTWARE)
  size                             136
  config                           0x9 (PERF_COUNT_SW_DUMMY)
  sample_type                      IP|TID|TIME|CPU
  read_format                      ID|LOST
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  mmap2                            1
  comm_exec                        1
  ksymbol                          1
  bpf_event                        1
  { wakeup_events, wakeup_watermark } 1
 ------------------------------------------------------------
sys_perf_event_open: pid 1189569  cpu 0  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
perf_evlist__open: Permission denied
 ---- end(-2) ----
Leak of file descriptor 6 that opened: 'pipe:[14200347]'
 ---- unexpected signal (6) ----
iFailed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
    #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311
    #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0
    #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44
    #3 0x7f29ce849cc2 in raise raise.c:27
    #4 0x7f29ce8324ac in abort abort.c:81
    #5 0x565358f662d4 in check_leaks builtin-test.c:226
    #6 0x565358f6682e in run_test_child builtin-test.c:344
    #7 0x565358ef7121 in start_command run-command.c:128
    #8 0x565358f67273 in start_test builtin-test.c:545
    #9 0x565358f6771d in __cmd_test builtin-test.c:647
    #10 0x565358f682bd in cmd_test builtin-test.c:849
    #11 0x565358ee5ded in run_builtin perf.c:349
    #12 0x565358ee6085 in handle_internal_command perf.c:401
    #13 0x565358ee61de in run_argv perf.c:448
    #14 0x565358ee6527 in main perf.c:555
    #15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74
    #16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    #17 0x565358e391c1 in _start perf[851c1]
  7: PERF_RECORD_* events & perf_sample fields                       : FAILED!
```

After:
```
$ perf test 7
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object")
Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Chun-Tse Shao <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
github-actions bot pushed a commit that referenced this pull request Oct 25, 2025
… 'T'

When perf report with annotation for a symbol, press 's' and 'T', then exit
the annotate browser. Once annotate the same symbol, the annotate browser
will crash.

The browser.arch was required to be correctly updated when data type
feature was enabled by 'T'. Usually it was initialized by symbol__annotate2
function. If a symbol has already been correctly annotated at the first
time, it should not call the symbol__annotate2 function again, thus the
browser.arch will not get initialized. Then at the second time to show the
annotate browser, the data type needs to be displayed but the browser.arch
is empty.

Stack trace as below:

Perf: Segmentation fault
-------- backtrace --------
    #0 0x55d365 in ui__signal_backtrace setup.c:0
    #1 0x7f5ff1a3e930 in __restore_rt libc.so.6[3e930]
    #2 0x570f08 in arch__is perf[570f08]
    #3 0x562186 in annotate_get_insn_location perf[562186]
    #4 0x562626 in __hist_entry__get_data_type annotate.c:0
    #5 0x56476d in annotation_line__write perf[56476d]
    #6 0x54e2db in annotate_browser__write annotate.c:0
    #7 0x54d061 in ui_browser__list_head_refresh perf[54d061]
    #8 0x54dc9e in annotate_browser__refresh annotate.c:0
    #9 0x54c03d in __ui_browser__refresh browser.c:0
    #10 0x54ccf8 in ui_browser__run perf[54ccf8]
    #11 0x54eb92 in __hist_entry__tui_annotate perf[54eb92]
    #12 0x552293 in do_annotate hists.c:0
    #13 0x55941c in evsel__hists_browse hists.c:0
    #14 0x55b00f in evlist__tui_browse_hists perf[55b00f]
    #15 0x42ff02 in cmd_report perf[42ff02]
    #16 0x494008 in run_builtin perf.c:0
    #17 0x494305 in handle_internal_command perf.c:0
    #18 0x410547 in main perf[410547]
    #19 0x7f5ff1a295d0 in __libc_start_call_main libc.so.6[295d0]
    #20 0x7f5ff1a29680 in __libc_start_main@@GLIBC_2.34 libc.so.6[29680]
    #21 0x410b75 in _start perf[410b75]

Fixes: 1d4374a ("perf annotate: Add 'T' hot key to toggle data type display")
Reviewed-by: James Clark <[email protected]>
Tested-by: Namhyung Kim <[email protected]>
Signed-off-by: Tianyou Li <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 5, 2025
When using perf record with the `--overwrite` option, a segmentation fault
occurs if an event fails to open. For example:

  perf record -e cycles-ct -F 1000 -a --overwrite
  Error:
  cycles-ct:H: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
  perf: Segmentation fault
      #0 0x6466b6 in dump_stack debug.c:366
      #1 0x646729 in sighandler_dump_stack debug.c:378
      #2 0x453fd1 in sigsegv_handler builtin-record.c:722
      #3 0x7f8454e65090 in __restore_rt libc-2.32.so[54090]
      #4 0x6c5671 in __perf_event__synthesize_id_index synthetic-events.c:1862
      #5 0x6c5ac0 in perf_event__synthesize_id_index synthetic-events.c:1943
      #6 0x458090 in record__synthesize builtin-record.c:2075
      #7 0x45a85a in __cmd_record builtin-record.c:2888
      #8 0x45deb6 in cmd_record builtin-record.c:4374
      #9 0x4e5e33 in run_builtin perf.c:349
      #10 0x4e60bf in handle_internal_command perf.c:401
      #11 0x4e6215 in run_argv perf.c:448
      #12 0x4e653a in main perf.c:555
      #13 0x7f8454e4fa72 in __libc_start_main libc-2.32.so[3ea72]
      #14 0x43a3ee in _start ??:0

The --overwrite option implies --tail-synthesize, which collects non-sample
events reflecting the system status when recording finishes. However, when
evsel opening fails (e.g., unsupported event 'cycles-ct'), session->evlist
is not initialized and remains NULL. The code unconditionally calls
record__synthesize() in the error path, which iterates through the NULL
evlist pointer and causes a segfault.

To fix it, move the record__synthesize() call inside the error check block, so
it's only called when there was no error during recording, ensuring that evlist
is properly initialized.

Fixes: 4ea648a ("perf record: Add --tail-synthesize option")
Signed-off-by: Shuai Xue <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 25, 2025
On systems using the hash MMU, there is a software SLB preload cache that
mirrors the entries loaded into the hardware SLB buffer. This preload
cache is subject to periodic eviction — typically after every 256 context
switches — to remove old entry.

To optimize performance, the kernel skips switch_mmu_context() in
switch_mm_irqs_off() when the prev and next mm_struct are the same.
However, on hash MMU systems, this can lead to inconsistencies between
the hardware SLB and the software preload cache.

If an SLB entry for a process is evicted from the software cache on one
CPU, and the same process later runs on another CPU without executing
switch_mmu_context(), the hardware SLB may retain stale entries. If the
kernel then attempts to reload that entry, it can trigger an SLB
multi-hit error.

The following timeline shows how stale SLB entries are created and can
cause a multi-hit error when a process moves between CPUs without a
MMU context switch.

CPU 0                                   CPU 1
-----                                    -----
Process P
exec                                    swapper/1
 load_elf_binary
  begin_new_exc
    activate_mm
     switch_mm_irqs_off
      switch_mmu_context
       switch_slb
       /*
        * This invalidates all
        * the entries in the HW
        * and setup the new HW
        * SLB entries as per the
        * preload cache.
        */
context_switch
sched_migrate_task migrates process P to cpu-1

Process swapper/0                       context switch (to process P)
(uses mm_struct of Process P)           switch_mm_irqs_off()
                                         switch_slb
                                           load_slb++
                                            /*
                                            * load_slb becomes 0 here
                                            * and we evict an entry from
                                            * the preload cache with
                                            * preload_age(). We still
                                            * keep HW SLB and preload
                                            * cache in sync, that is
                                            * because all HW SLB entries
                                            * anyways gets evicted in
                                            * switch_slb during SLBIA.
                                            * We then only add those
                                            * entries back in HW SLB,
                                            * which are currently
                                            * present in preload_cache
                                            * (after eviction).
                                            */
                                        load_elf_binary continues...
                                         setup_new_exec()
                                          slb_setup_new_exec()

                                        sched_switch event
                                        sched_migrate_task migrates
                                        process P to cpu-0

context_switch from swapper/0 to Process P
 switch_mm_irqs_off()
  /*
   * Since both prev and next mm struct are same we don't call
   * switch_mmu_context(). This will cause the HW SLB and SW preload
   * cache to go out of sync in preload_new_slb_context. Because there
   * was an SLB entry which was evicted from both HW and preload cache
   * on cpu-1. Now later in preload_new_slb_context(), when we will try
   * to add the same preload entry again, we will add this to the SW
   * preload cache and then will add it to the HW SLB. Since on cpu-0
   * this entry was never invalidated, hence adding this entry to the HW
   * SLB will cause a SLB multi-hit error.
   */
load_elf_binary continues...
 START_THREAD
  start_thread
   preload_new_slb_context
   /*
    * This tries to add a new EA to preload cache which was earlier
    * evicted from both cpu-1 HW SLB and preload cache. This caused the
    * HW SLB of cpu-0 to go out of sync with the SW preload cache. The
    * reason for this was, that when we context switched back on CPU-0,
    * we should have ideally called switch_mmu_context() which will
    * bring the HW SLB entries on CPU-0 in sync with SW preload cache
    * entries by setting up the mmu context properly. But we didn't do
    * that since the prev mm_struct running on cpu-0 was same as the
    * next mm_struct (which is true for swapper / kernel threads). So
    * now when we try to add this new entry into the HW SLB of cpu-0,
    * we hit a SLB multi-hit error.
    */

WARNING: CPU: 0 PID: 1810970 at arch/powerpc/mm/book3s64/slb.c:62
assert_slb_presence+0x2c/0x50(48 results) 02:47:29 [20157/42149]
Modules linked in:
CPU: 0 UID: 0 PID: 1810970 Comm: dd Not tainted 6.16.0-rc3-dirty #12
VOLUNTARY
Hardware name: IBM pSeries (emulated by qemu) POWER8 (architected)
0x4d0200 0xf000004 of:SLOF,HEAD hv:linux,kvm pSeries
NIP:  c00000000015426c LR: c0000000001543b4 CTR: 0000000000000000
REGS: c0000000497c77e0 TRAP: 0700   Not tainted  (6.16.0-rc3-dirty)
MSR:  8000000002823033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE>  CR: 28888482  XER: 00000000
CFAR: c0000000001543b0 IRQMASK: 3
<...>
NIP [c00000000015426c] assert_slb_presence+0x2c/0x50
LR [c0000000001543b4] slb_insert_entry+0x124/0x390
Call Trace:
  0x7fffceb5ffff (unreliable)
  preload_new_slb_context+0x100/0x1a0
  start_thread+0x26c/0x420
  load_elf_binary+0x1b04/0x1c40
  bprm_execve+0x358/0x680
  do_execveat_common+0x1f8/0x240
  sys_execve+0x58/0x70
  system_call_exception+0x114/0x300
  system_call_common+0x160/0x2c4

>From the above analysis, during early exec the hardware SLB is cleared,
and entries from the software preload cache are reloaded into hardware
by switch_slb. However, preload_new_slb_context and slb_setup_new_exec
also attempt to load some of the same entries, which can trigger a
multi-hit. In most cases, these additional preloads simply hit existing
entries and add nothing new. Removing these functions avoids redundant
preloads and eliminates the multi-hit issue. This patch removes these
two functions.

We tested process switching performance using the context_switch
benchmark on POWER9/hash, and observed no regression.

Without this patch: 129041 ops/sec
With this patch:    129341 ops/sec

We also measured SLB faults during boot, and the counts are essentially
the same with and without this patch.

SLB faults without this patch: 19727
SLB faults with this patch:    19786

Fixes: 5434ae7 ("powerpc/64s/hash: Add a SLB preload cache")
cc: [email protected]
Suggested-by: Nicholas Piggin <[email protected]>
Signed-off-by: Donet Tom <[email protected]>
Signed-off-by: Ritesh Harjani (IBM) <[email protected]>
Signed-off-by: Madhavan Srinivasan <[email protected]>
Link: https://patch.msgid.link/0ac694ae683494fe8cadbd911a1a5018d5d3c541.1761834163.git.ritesh.list@gmail.com
github-actions bot pushed a commit that referenced this pull request Nov 29, 2025
Marc Kleine-Budde <[email protected]> says:

Similarly to how CAN FD reuses the bittiming logic of Classical CAN, CAN XL
also reuses the entirety of CAN FD features, and, on top of that, adds new
features which are specific to CAN XL.

A so-called 'mixed-mode' is intended to have (XL-tolerant) CAN FD nodes and
CAN XL nodes on one CAN segment, where the FD-controllers can talk CC/FD
and the XL-controllers can talk CC/FD/XL. This mixed-mode utilizes the
known error-signalling (ES) for sending CC/FD/XL frames. For CAN FD and CAN
XL the tranceiver delay compensation (TDC) is supported to use common CAN
and CAN-SIG transceivers.

The CANXL-only mode disables the error-signalling in the CAN XL controller.
This mode does not allow CC/FD frames to be sent but additionally offers a
CAN XL transceiver mode switching (TMS) to send CAN XL frames with up to
20Mbit/s data rate. The TMS utilizes a PWM configuration which is added to
the netlink interface.

Configured with CAN_CTRLMODE_FD and CAN_CTRLMODE_XL this leads to:

FD=0 XL=0 CC-only mode         (ES=1)
FD=1 XL=0 FD/CC mixed-mode     (ES=1)
FD=1 XL=1 XL/FD/CC mixed-mode  (ES=1)
FD=0 XL=1 XL-only mode         (ES=0, TMS optional)

Patch #1 print defined ctrlmode strings capitalized to increase the
readability and to be in line with the 'ip' tool (iproute2).

Patch #2 is a small clean-up which makes can_calc_bittiming() use
NL_SET_ERR_MSG() instead of netdev_err().

Patch #3 adds a check in can_dev_dropped_skb() to drop CAN FD frames
when CAN FD is turned off.

Patch #4 adds CAN_CTRLMODE_RESTRICTED. Note that contrary to the other
CAN_CTRL_MODE_XL_* that are introduced in the later patches, this control
mode is not specific to CAN XL. The nuance is that because this restricted
mode was only added in ISO 11898-1:2024, it is made mandatory for CAN XL
devices but optional for other protocols. This is why this patch is added
as a preparation before introducing the core CAN XL logic.

Patch #5 adds all the CAN XL features which are inherited from CAN FD: the
nominal bittiming, the data bittiming and the TDC.

Patch #6 add a new CAN_CTRLMODE_XL_TMS control mode which is specific to
CAN XL to enable the transceiver mode switching (TMS) in XL-only mode.

Patch #7 adds a check in can_dev_dropped_skb() to drop CAN CC/FD frames
when the CAN XL controller is in CAN XL-only mode. The introduced
can_dev_in_xl_only_mode() function also determines the error-signalling
configuration for the CAN XL controllers.

Patch #8 to #11 add the PWM logic for the CAN XL TMS mode.

Patch #12 to #14 add different default sample-points for standard CAN and
CAN SIG transceivers (with TDC) and CAN XL transceivers using PWM in the
CAN XL TMS mode.

Patch #15 add a dummy_can driver for netlink testing and debugging.

Patch #16 check CAN frame type (CC/FD/XL) when writing those frames to the
CAN_RAW socket and reject them if it's not supported by the CAN interface.

Patch #17 increase the resolution when printing the bitrate error and
round-up the value to 0.01% in the case the resolution would still provide
values which would lead to 0.00%.

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
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3 participants