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…evicesinc/hdl/commit/3e57ff1fc55480f6d4dcde0488e9d54a9d758501

@mhennerich mhennerich merged commit 99bea54 into analogdevicesinc:xcomm_zynq Jun 21, 2017
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Tested and merged.

Thanks for contributing!

-Michael

mhennerich added a commit that referenced this pull request Jun 21, 2017
commodo pushed a commit that referenced this pull request Jul 16, 2018
Wire up io_pgetevents system call on powerpc.

io_pgetevents is a new syscall to read asynchronous I/O events from the
completion queue.

Tested with libaio branch aio-poll[1] and the io_pgetevents test (#22) passed
on both ppc64 LE and BE modes.

[1] https://pagure.io/libaio/branch/aio-poll

CC: Christoph Hellwig <[email protected]>
Signed-off-by: Breno Leitao <[email protected]>
Acked-by: Christoph Hellwig <[email protected]>
Signed-off-by: Michael Ellerman <[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]>
UtsavAgarwalADI pushed a commit that referenced this pull request Jan 26, 2024
We call bnxt_half_open_nic() to setup the chip partially to run
loopback tests.  The rings and buffers are initialized normally
so that we can transmit and receive packets in loopback mode.
That means page pool buffers are allocated for the aggregation ring
just like the normal case.  NAPI is not needed because we are just
polling for the loopback packets.

When we're done with the loopback tests, we call bnxt_half_close_nic()
to clean up.  When freeing the page pools, we hit a WARN_ON()
in page_pool_unlink_napi() because the NAPI state linked to the
page pool is uninitialized.

The simplest way to avoid this warning is just to initialize the
NAPIs during half open and delete the NAPIs during half close.
Trying to skip the page pool initialization or skip linking of
NAPI during half open will be more complicated.

This fix avoids this warning:

WARNING: CPU: 4 PID: 46967 at net/core/page_pool.c:946 page_pool_unlink_napi+0x1f/0x30
CPU: 4 PID: 46967 Comm: ethtool Tainted: G S      W          6.7.0-rc5+ #22
Hardware name: Dell Inc. PowerEdge R750/06V45N, BIOS 1.3.8 08/31/2021
RIP: 0010:page_pool_unlink_napi+0x1f/0x30
Code: 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 8b 47 18 48 85 c0 74 1b 48 8b 50 10 83 e2 01 74 08 8b 40 34 83 f8 ff 74 02 <0f> 0b 48 c7 47 18 00 00 00 00 c3 cc cc cc cc 66 90 90 90 90 90 90
RSP: 0018:ffa000003d0dfbe8 EFLAGS: 00010246
RAX: ff110003607ce640 RBX: ff110010baf5d000 RCX: 0000000000000008
RDX: 0000000000000000 RSI: ff110001e5e522c0 RDI: ff110010baf5d000
RBP: ff11000145539b40 R08: 0000000000000001 R09: ffffffffc063f641
R10: ff110001361eddb8 R11: 000000000040000f R12: 0000000000000001
R13: 000000000000001c R14: ff1100014553a080 R15: 0000000000003fc0
FS:  00007f9301c4f740(0000) GS:ff1100103fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f91344fa8f0 CR3: 00000003527cc005 CR4: 0000000000771ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 <TASK>
 ? __warn+0x81/0x140
 ? page_pool_unlink_napi+0x1f/0x30
 ? report_bug+0x102/0x200
 ? handle_bug+0x44/0x70
 ? exc_invalid_op+0x13/0x60
 ? asm_exc_invalid_op+0x16/0x20
 ? bnxt_free_ring.isra.123+0xb1/0xd0 [bnxt_en]
 ? page_pool_unlink_napi+0x1f/0x30
 page_pool_destroy+0x3e/0x150
 bnxt_free_mem+0x441/0x5e0 [bnxt_en]
 bnxt_half_close_nic+0x2a/0x40 [bnxt_en]
 bnxt_self_test+0x21d/0x450 [bnxt_en]
 __dev_ethtool+0xeda/0x2e30
 ? native_queued_spin_lock_slowpath+0x17f/0x2b0
 ? __link_object+0xa1/0x160
 ? _raw_spin_unlock_irqrestore+0x23/0x40
 ? __create_object+0x5f/0x90
 ? __kmem_cache_alloc_node+0x317/0x3c0
 ? dev_ethtool+0x59/0x170
 dev_ethtool+0xa7/0x170
 dev_ioctl+0xc3/0x530
 sock_do_ioctl+0xa8/0xf0
 sock_ioctl+0x270/0x310
 __x64_sys_ioctl+0x8c/0xc0
 do_syscall_64+0x3e/0xf0
 entry_SYSCALL_64_after_hwframe+0x6e/0x76

Fixes: 294e39e ("bnxt: hook NAPIs to page pools")
Reviewed-by: Andy Gospodarek <[email protected]>
Reviewed-by: Ajit Khaparde <[email protected]>
Signed-off-by: Michael Chan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
UtsavAgarwalADI pushed a commit that referenced this pull request Feb 15, 2024
When configuring a hugetlb filesystem via the fsconfig() syscall, there is
a possible NULL dereference in hugetlbfs_fill_super() caused by assigning
NULL to ctx->hstate in hugetlbfs_parse_param() when the requested pagesize
is non valid.

E.g: Taking the following steps:

     fd = fsopen("hugetlbfs", FSOPEN_CLOEXEC);
     fsconfig(fd, FSCONFIG_SET_STRING, "pagesize", "1024", 0);
     fsconfig(fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0);

Given that the requested "pagesize" is invalid, ctxt->hstate will be replaced
with NULL, losing its previous value, and we will print an error:

 ...
 ...
 case Opt_pagesize:
 ps = memparse(param->string, &rest);
 ctx->hstate = h;
 if (!ctx->hstate) {
         pr_err("Unsupported page size %lu MB\n", ps / SZ_1M);
         return -EINVAL;
 }
 return 0;
 ...
 ...

This is a problem because later on, we will dereference ctxt->hstate in
hugetlbfs_fill_super()

 ...
 ...
 sb->s_blocksize = huge_page_size(ctx->hstate);
 ...
 ...

Causing below Oops.

Fix this by replacing cxt->hstate value only when then pagesize is known
to be valid.

 kernel: hugetlbfs: Unsupported page size 0 MB
 kernel: BUG: kernel NULL pointer dereference, address: 0000000000000028
 kernel: #PF: supervisor read access in kernel mode
 kernel: #PF: error_code(0x0000) - not-present page
 kernel: PGD 800000010f66c067 P4D 800000010f66c067 PUD 1b22f8067 PMD 0
 kernel: Oops: 0000 [#1] PREEMPT SMP PTI
 kernel: CPU: 4 PID: 5659 Comm: syscall Tainted: G            E      6.8.0-rc2-default+ #22 5a47c3fef76212addcc6eb71344aabc35190ae8f
 kernel: Hardware name: Intel Corp. GROVEPORT/GROVEPORT, BIOS GVPRCRB1.86B.0016.D04.1705030402 05/03/2017
 kernel: RIP: 0010:hugetlbfs_fill_super+0xb4/0x1a0
 kernel: Code: 48 8b 3b e8 3e c6 ed ff 48 85 c0 48 89 45 20 0f 84 d6 00 00 00 48 b8 ff ff ff ff ff ff ff 7f 4c 89 e7 49 89 44 24 20 48 8b 03 <8b> 48 28 b8 00 10 00 00 48 d3 e0 49 89 44 24 18 48 8b 03 8b 40 28
 kernel: RSP: 0018:ffffbe9960fcbd48 EFLAGS: 00010246
 kernel: RAX: 0000000000000000 RBX: ffff9af5272ae780 RCX: 0000000000372004
 kernel: RDX: ffffffffffffffff RSI: ffffffffffffffff RDI: ffff9af555e9b000
 kernel: RBP: ffff9af52ee66b00 R08: 0000000000000040 R09: 0000000000370004
 kernel: R10: ffffbe9960fcbd48 R11: 0000000000000040 R12: ffff9af555e9b000
 kernel: R13: ffffffffa66b86c0 R14: ffff9af507d2f400 R15: ffff9af507d2f400
 kernel: FS:  00007ffbc0ba4740(0000) GS:ffff9b0bd7000000(0000) knlGS:0000000000000000
 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 kernel: CR2: 0000000000000028 CR3: 00000001b1ee0000 CR4: 00000000001506f0
 kernel: Call Trace:
 kernel:  <TASK>
 kernel:  ? __die_body+0x1a/0x60
 kernel:  ? page_fault_oops+0x16f/0x4a0
 kernel:  ? search_bpf_extables+0x65/0x70
 kernel:  ? fixup_exception+0x22/0x310
 kernel:  ? exc_page_fault+0x69/0x150
 kernel:  ? asm_exc_page_fault+0x22/0x30
 kernel:  ? __pfx_hugetlbfs_fill_super+0x10/0x10
 kernel:  ? hugetlbfs_fill_super+0xb4/0x1a0
 kernel:  ? hugetlbfs_fill_super+0x28/0x1a0
 kernel:  ? __pfx_hugetlbfs_fill_super+0x10/0x10
 kernel:  vfs_get_super+0x40/0xa0
 kernel:  ? __pfx_bpf_lsm_capable+0x10/0x10
 kernel:  vfs_get_tree+0x25/0xd0
 kernel:  vfs_cmd_create+0x64/0xe0
 kernel:  __x64_sys_fsconfig+0x395/0x410
 kernel:  do_syscall_64+0x80/0x160
 kernel:  ? syscall_exit_to_user_mode+0x82/0x240
 kernel:  ? do_syscall_64+0x8d/0x160
 kernel:  ? syscall_exit_to_user_mode+0x82/0x240
 kernel:  ? do_syscall_64+0x8d/0x160
 kernel:  ? exc_page_fault+0x69/0x150
 kernel:  entry_SYSCALL_64_after_hwframe+0x6e/0x76
 kernel: RIP: 0033:0x7ffbc0cb87c9
 kernel: Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 97 96 0d 00 f7 d8 64 89 01 48
 kernel: RSP: 002b:00007ffc29d2f388 EFLAGS: 00000206 ORIG_RAX: 00000000000001af
 kernel: RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ffbc0cb87c9
 kernel: RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
 kernel: RBP: 00007ffc29d2f3b0 R08: 0000000000000000 R09: 0000000000000000
 kernel: R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
 kernel: R13: 00007ffc29d2f4c0 R14: 0000000000000000 R15: 0000000000000000
 kernel:  </TASK>
 kernel: Modules linked in: rpcsec_gss_krb5(E) auth_rpcgss(E) nfsv4(E) dns_resolver(E) nfs(E) lockd(E) grace(E) sunrpc(E) netfs(E) af_packet(E) bridge(E) stp(E) llc(E) iscsi_ibft(E) iscsi_boot_sysfs(E) intel_rapl_msr(E) intel_rapl_common(E) iTCO_wdt(E) intel_pmc_bxt(E) sb_edac(E) iTCO_vendor_support(E) x86_pkg_temp_thermal(E) intel_powerclamp(E) coretemp(E) kvm_intel(E) rfkill(E) ipmi_ssif(E) kvm(E) acpi_ipmi(E) irqbypass(E) pcspkr(E) igb(E) ipmi_si(E) mei_me(E) i2c_i801(E) joydev(E) intel_pch_thermal(E) i2c_smbus(E) dca(E) lpc_ich(E) mei(E) ipmi_devintf(E) ipmi_msghandler(E) acpi_pad(E) tiny_power_button(E) button(E) fuse(E) efi_pstore(E) configfs(E) ip_tables(E) x_tables(E) ext4(E) mbcache(E) jbd2(E) hid_generic(E) usbhid(E) sd_mod(E) t10_pi(E) crct10dif_pclmul(E) crc32_pclmul(E) crc32c_intel(E) polyval_clmulni(E) ahci(E) xhci_pci(E) polyval_generic(E) gf128mul(E) ghash_clmulni_intel(E) sha512_ssse3(E) sha256_ssse3(E) xhci_pci_renesas(E) libahci(E) ehci_pci(E) sha1_ssse3(E) xhci_hcd(E) ehci_hcd(E) libata(E)
 kernel:  mgag200(E) i2c_algo_bit(E) usbcore(E) wmi(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) scsi_common(E) aesni_intel(E) crypto_simd(E) cryptd(E)
 kernel: Unloaded tainted modules: acpi_cpufreq(E):1 fjes(E):1
 kernel: CR2: 0000000000000028
 kernel: ---[ end trace 0000000000000000 ]---
 kernel: RIP: 0010:hugetlbfs_fill_super+0xb4/0x1a0
 kernel: Code: 48 8b 3b e8 3e c6 ed ff 48 85 c0 48 89 45 20 0f 84 d6 00 00 00 48 b8 ff ff ff ff ff ff ff 7f 4c 89 e7 49 89 44 24 20 48 8b 03 <8b> 48 28 b8 00 10 00 00 48 d3 e0 49 89 44 24 18 48 8b 03 8b 40 28
 kernel: RSP: 0018:ffffbe9960fcbd48 EFLAGS: 00010246
 kernel: RAX: 0000000000000000 RBX: ffff9af5272ae780 RCX: 0000000000372004
 kernel: RDX: ffffffffffffffff RSI: ffffffffffffffff RDI: ffff9af555e9b000
 kernel: RBP: ffff9af52ee66b00 R08: 0000000000000040 R09: 0000000000370004
 kernel: R10: ffffbe9960fcbd48 R11: 0000000000000040 R12: ffff9af555e9b000
 kernel: R13: ffffffffa66b86c0 R14: ffff9af507d2f400 R15: ffff9af507d2f400
 kernel: FS:  00007ffbc0ba4740(0000) GS:ffff9b0bd7000000(0000) knlGS:0000000000000000
 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 kernel: CR2: 0000000000000028 CR3: 00000001b1ee0000 CR4: 00000000001506f0

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 3202198 ("hugetlbfs: Convert to fs_context")
Signed-off-by: Michal Hocko <[email protected]>
Signed-off-by: Oscar Salvador <[email protected]>
Acked-by: Muchun Song <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Jun 4, 2025
…stamping

The stmmac platform drivers that do not open-code the clk_ptp_rate value
after having retrieved the default one from the device-tree can end up
with 0 in clk_ptp_rate (as clk_get_rate can return 0). It will
eventually propagate up to PTP initialization when bringing up the
interface, leading to a divide by 0:

 Division by zero in kernel.
 CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.30-00001-g48313bd5768a #22
 Hardware name: STM32 (Device Tree Support)
 Call trace:
  unwind_backtrace from show_stack+0x18/0x1c
  show_stack from dump_stack_lvl+0x6c/0x8c
  dump_stack_lvl from Ldiv0_64+0x8/0x18
  Ldiv0_64 from stmmac_init_tstamp_counter+0x190/0x1a4
  stmmac_init_tstamp_counter from stmmac_hw_setup+0xc1c/0x111c
  stmmac_hw_setup from __stmmac_open+0x18c/0x434
  __stmmac_open from stmmac_open+0x3c/0xbc
  stmmac_open from __dev_open+0xf4/0x1ac
  __dev_open from __dev_change_flags+0x1cc/0x224
  __dev_change_flags from dev_change_flags+0x24/0x60
  dev_change_flags from ip_auto_config+0x2e8/0x11a0
  ip_auto_config from do_one_initcall+0x84/0x33c
  do_one_initcall from kernel_init_freeable+0x1b8/0x214
  kernel_init_freeable from kernel_init+0x24/0x140
  kernel_init from ret_from_fork+0x14/0x28
 Exception stack(0xe0815fb0 to 0xe0815ff8)

Prevent this division by 0 by adding an explicit check and error log
about the actual issue. While at it, remove the same check from
stmmac_ptp_register, which then becomes duplicate

Fixes: 19d857c ("stmmac: Fix calculations for ptp counters when clock input = 50Mhz.")
Signed-off-by: Alexis Lothoré <[email protected]>
Reviewed-by: Yanteng Si <[email protected]>
Reviewed-by: Maxime Chevallier <[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 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]>
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]>
nunojsa pushed a commit that referenced this pull request Aug 5, 2025
commit f1897f2 upstream.

syzkaller reported such a BUG_ON():

 ------------[ cut here ]------------
 kernel BUG at mm/khugepaged.c:1835!
 Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
 ...
 CPU: 6 UID: 0 PID: 8009 Comm: syz.15.106 Kdump: loaded Tainted: G        W          6.13.0-rc6 #22
 Tainted: [W]=WARN
 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
 pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : collapse_file+0xa44/0x1400
 lr : collapse_file+0x88/0x1400
 sp : ffff80008afe3a60
 ...
 Call trace:
  collapse_file+0xa44/0x1400 (P)
  hpage_collapse_scan_file+0x278/0x400
  madvise_collapse+0x1bc/0x678
  madvise_vma_behavior+0x32c/0x448
  madvise_walk_vmas.constprop.0+0xbc/0x140
  do_madvise.part.0+0xdc/0x2c8
  __arm64_sys_madvise+0x68/0x88
  invoke_syscall+0x50/0x120
  el0_svc_common.constprop.0+0xc8/0xf0
  do_el0_svc+0x24/0x38
  el0_svc+0x34/0x128
  el0t_64_sync_handler+0xc8/0xd0
  el0t_64_sync+0x190/0x198

This indicates that the pgoff is unaligned.  After analysis, I confirm the
vma is mapped to /dev/zero.  Such a vma certainly has vm_file, but it is
set to anonymous by mmap_zero().  So even if it's mmapped by 2m-unaligned,
it can pass the check in thp_vma_allowable_order() as it is an
anonymous-mmap, but then be collapsed as a file-mmap.

It seems the problem has existed for a long time, but actually, since we
have khugepaged_max_ptes_none check before, we will skip collapse it as it
is /dev/zero and so has no present page.  But commit d8ea7cc limit
the check for only khugepaged, so the BUG_ON() can be triggered by
madvise_collapse().

Add vma_is_anonymous() check to make such vma be processed by
hpage_collapse_scan_pmd().

Link: https://lkml.kernel.org/r/[email protected]
Fixes: d8ea7cc ("mm/khugepaged: add flag to predicate khugepaged-only behavior")
Signed-off-by: Liu Shixin <[email protected]>
Reviewed-by: Yang Shi <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Chengming Zhou <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Mattew Wilcox <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Nanyong Sun <[email protected]>
Cc: Qi Zheng <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
[acsjakub: backport, clean apply]
Signed-off-by: Jakub Acs <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 5, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 6, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 9, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 9, 2025
If we have 2 instances of sbs-charger in the DTS, the driver probe for the second instance will fail:

[    8.012874] sbs-battery 18-000b: sbs-battery: battery gas gauge device registered
[    8.039094] sbs-charger 18-0009: ltc4100: smart charger device registered
[    8.112911] sbs-battery 20-000b: sbs-battery: battery gas gauge device registered
[    8.134533] sysfs: cannot create duplicate filename '/class/power_supply/sbs-charger'
[    8.143871] CPU: 3 PID: 295 Comm: systemd-udevd Tainted: G           O      5.10.147 #22
[    8.151974] Hardware name: ALE AMB (DT)
[    8.155828] Call trace:
[    8.158292]  dump_backtrace+0x0/0x1d4
[    8.161960]  show_stack+0x18/0x6c
[    8.165280]  dump_stack+0xcc/0x128
[    8.168687]  sysfs_warn_dup+0x60/0x7c
[    8.172353]  sysfs_do_create_link_sd+0xf0/0x100
[    8.176886]  sysfs_create_link+0x20/0x40
[    8.180816]  device_add+0x270/0x7a4
[    8.184311]  __power_supply_register+0x304/0x560
[    8.188930]  devm_power_supply_register+0x54/0xa0
[    8.193644]  sbs_probe+0xc0/0x214 [sbs_charger]
[    8.198183]  i2c_device_probe+0x2dc/0x2f4
[    8.202196]  really_probe+0xf0/0x510
[    8.205774]  driver_probe_device+0xfc/0x160
[    8.209960]  device_driver_attach+0xc0/0xcc
[    8.214146]  __driver_attach+0xc0/0x170
[    8.218002]  bus_for_each_dev+0x74/0xd4
[    8.221862]  driver_attach+0x24/0x30
[    8.225444]  bus_add_driver+0x148/0x250
[    8.229283]  driver_register+0x78/0x130
[    8.233140]  i2c_register_driver+0x4c/0xe0
[    8.237250]  sbs_driver_init+0x20/0x1000 [sbs_charger]
[    8.242424]  do_one_initcall+0x50/0x1b0
[    8.242434]  do_init_module+0x44/0x230
[    8.242438]  load_module+0x2200/0x27c0
[    8.242442]  __do_sys_finit_module+0xa8/0x11c
[    8.242447]  __arm64_sys_finit_module+0x20/0x30
[    8.242457]  el0_svc_common.constprop.0+0x64/0x154
[    8.242464]  do_el0_svc+0x24/0x8c
[    8.242474]  el0_svc+0x10/0x20
[    8.242481]  el0_sync_handler+0x108/0x114
[    8.242485]  el0_sync+0x180/0x1c0
[    8.243847] sbs-charger 20-0009: Failed to register power supply
[    8.287934] sbs-charger: probe of 20-0009 failed with error -17

This is mainly because the "name" field of power_supply_desc is a constant.
This patch fixes the issue by reusing the same approach as sbs-battery.
With this patch, the result is:
[    7.819532] sbs-charger 18-0009: ltc4100: smart charger device registered
[    7.825305] sbs-battery 18-000b: sbs-battery: battery gas gauge device registered
[    7.887423] sbs-battery 20-000b: sbs-battery: battery gas gauge device registered
[    7.893501] sbs-charger 20-0009: ltc4100: smart charger device registered

Signed-off-by: Fabien Proriol <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 10, 2025
If we have 2 instances of sbs-charger in the DTS, the driver probe for the second instance will fail:

[    8.012874] sbs-battery 18-000b: sbs-battery: battery gas gauge device registered
[    8.039094] sbs-charger 18-0009: ltc4100: smart charger device registered
[    8.112911] sbs-battery 20-000b: sbs-battery: battery gas gauge device registered
[    8.134533] sysfs: cannot create duplicate filename '/class/power_supply/sbs-charger'
[    8.143871] CPU: 3 PID: 295 Comm: systemd-udevd Tainted: G           O      5.10.147 #22
[    8.151974] Hardware name: ALE AMB (DT)
[    8.155828] Call trace:
[    8.158292]  dump_backtrace+0x0/0x1d4
[    8.161960]  show_stack+0x18/0x6c
[    8.165280]  dump_stack+0xcc/0x128
[    8.168687]  sysfs_warn_dup+0x60/0x7c
[    8.172353]  sysfs_do_create_link_sd+0xf0/0x100
[    8.176886]  sysfs_create_link+0x20/0x40
[    8.180816]  device_add+0x270/0x7a4
[    8.184311]  __power_supply_register+0x304/0x560
[    8.188930]  devm_power_supply_register+0x54/0xa0
[    8.193644]  sbs_probe+0xc0/0x214 [sbs_charger]
[    8.198183]  i2c_device_probe+0x2dc/0x2f4
[    8.202196]  really_probe+0xf0/0x510
[    8.205774]  driver_probe_device+0xfc/0x160
[    8.209960]  device_driver_attach+0xc0/0xcc
[    8.214146]  __driver_attach+0xc0/0x170
[    8.218002]  bus_for_each_dev+0x74/0xd4
[    8.221862]  driver_attach+0x24/0x30
[    8.225444]  bus_add_driver+0x148/0x250
[    8.229283]  driver_register+0x78/0x130
[    8.233140]  i2c_register_driver+0x4c/0xe0
[    8.237250]  sbs_driver_init+0x20/0x1000 [sbs_charger]
[    8.242424]  do_one_initcall+0x50/0x1b0
[    8.242434]  do_init_module+0x44/0x230
[    8.242438]  load_module+0x2200/0x27c0
[    8.242442]  __do_sys_finit_module+0xa8/0x11c
[    8.242447]  __arm64_sys_finit_module+0x20/0x30
[    8.242457]  el0_svc_common.constprop.0+0x64/0x154
[    8.242464]  do_el0_svc+0x24/0x8c
[    8.242474]  el0_svc+0x10/0x20
[    8.242481]  el0_sync_handler+0x108/0x114
[    8.242485]  el0_sync+0x180/0x1c0
[    8.243847] sbs-charger 20-0009: Failed to register power supply
[    8.287934] sbs-charger: probe of 20-0009 failed with error -17

This is mainly because the "name" field of power_supply_desc is a constant.
This patch fixes the issue by reusing the same approach as sbs-battery.
With this patch, the result is:
[    7.819532] sbs-charger 18-0009: ltc4100: smart charger device registered
[    7.825305] sbs-battery 18-000b: sbs-battery: battery gas gauge device registered
[    7.887423] sbs-battery 20-000b: sbs-battery: battery gas gauge device registered
[    7.893501] sbs-charger 20-0009: ltc4100: smart charger device registered

Signed-off-by: Fabien Proriol <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 11, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 12, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 13, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 16, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 17, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 18, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
dlech pushed a commit that referenced this pull request Sep 23, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Oct 22, 2025
Calling intotify_show_fdinfo() on fd watching an overlayfs inode, while
the overlayfs is being unmounted, can lead to dereferencing NULL ptr.

This issue was found by syzkaller.

Race Condition Diagram:

Thread 1                           Thread 2
--------                           --------

generic_shutdown_super()
 shrink_dcache_for_umount
  sb->s_root = NULL

                    |
                    |             vfs_read()
                    |              inotify_fdinfo()
                    |               * inode get from mark *
                    |               show_mark_fhandle(m, inode)
                    |                exportfs_encode_fid(inode, ..)
                    |                 ovl_encode_fh(inode, ..)
                    |                  ovl_check_encode_origin(inode)
                    |                   * deref i_sb->s_root *
                    |
                    |
                    v
 fsnotify_sb_delete(sb)

Which then leads to:

[   32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[   32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
[   32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none)

<snip registers, unreliable trace>

[   32.143353] Call Trace:
[   32.143732]  ovl_encode_fh+0xd5/0x170
[   32.144031]  exportfs_encode_inode_fh+0x12f/0x300
[   32.144425]  show_mark_fhandle+0xbe/0x1f0
[   32.145805]  inotify_fdinfo+0x226/0x2d0
[   32.146442]  inotify_show_fdinfo+0x1c5/0x350
[   32.147168]  seq_show+0x530/0x6f0
[   32.147449]  seq_read_iter+0x503/0x12a0
[   32.148419]  seq_read+0x31f/0x410
[   32.150714]  vfs_read+0x1f0/0x9e0
[   32.152297]  ksys_read+0x125/0x240

IOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set
to NULL in the unmount path.

Fix it by protecting calling exportfs_encode_fid() from
show_mark_fhandle() with s_umount lock.

This form of fix was suggested by Amir in [1].

[1]: https://lore.kernel.org/all/CAOQ4uxhbDwhb+2Brs1UdkoF0a3NSdBAOQPNfEHjahrgoKJpLEw@mail.gmail.com/

Fixes: c45beeb ("ovl: support encoding fid from inode with no alias")
Signed-off-by: Jakub Acs <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Amir Goldstein <[email protected]>
Cc: Miklos Szeredi <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Jan Kara <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 12, 2025
Typically copynotify stateid is freed either when parent's stateid
is being close/freed or in nfsd4_laundromat if the stateid hasn't
been used in a lease period.

However, in case when the server got an OPEN (which created
a parent stateid), followed by a COPY_NOTIFY using that stateid,
followed by a client reboot. New client instance while doing
CREATE_SESSION would force expire previous state of this client.
It leads to the open state being freed thru release_openowner->
nfs4_free_ol_stateid() and it finds that it still has copynotify
stateid associated with it. We currently print a warning and is
triggerred

WARNING: CPU: 1 PID: 8858 at fs/nfsd/nfs4state.c:1550 nfs4_free_ol_stateid+0xb0/0x100 [nfsd]

This patch, instead, frees the associated copynotify stateid here.

If the parent stateid is freed (without freeing the copynotify
stateids associated with it), it leads to the list corruption
when laundromat ends up freeing the copynotify state later.

[ 1626.839430] Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
[ 1626.842828] Modules linked in: nfnetlink_queue nfnetlink_log bluetooth cfg80211 rpcrdma rdma_cm iw_cm ib_cm ib_core nfsd nfs_acl lockd grace nfs_localio ext4 crc16 mbcache jbd2 overlay uinput snd_seq_dummy snd_hrtimer qrtr rfkill vfat fat uvcvideo snd_hda_codec_generic videobuf2_vmalloc videobuf2_memops snd_hda_intel uvc snd_intel_dspcfg videobuf2_v4l2 videobuf2_common snd_hda_codec snd_hda_core videodev snd_hwdep snd_seq mc snd_seq_device snd_pcm snd_timer snd soundcore sg loop auth_rpcgss vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vmw_vmci vsock xfs 8021q garp stp llc mrp nvme ghash_ce e1000e nvme_core sr_mod nvme_keyring nvme_auth cdrom vmwgfx drm_ttm_helper ttm sunrpc dm_mirror dm_region_hash dm_log iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi fuse dm_multipath dm_mod nfnetlink
[ 1626.855594] CPU: 2 UID: 0 PID: 199 Comm: kworker/u24:33 Kdump: loaded Tainted: G    B   W           6.17.0-rc7+ #22 PREEMPT(voluntary)
[ 1626.857075] Tainted: [B]=BAD_PAGE, [W]=WARN
[ 1626.857573] Hardware name: VMware, Inc. VMware20,1/VBSA, BIOS VMW201.00V.24006586.BA64.2406042154 06/04/2024
[ 1626.858724] Workqueue: nfsd4 laundromat_main [nfsd]
[ 1626.859304] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[ 1626.860010] pc : __list_del_entry_valid_or_report+0x148/0x200
[ 1626.860601] lr : __list_del_entry_valid_or_report+0x148/0x200
[ 1626.861182] sp : ffff8000881d7a40
[ 1626.861521] x29: ffff8000881d7a40 x28: 0000000000000018 x27: ffff0000c2a98200
[ 1626.862260] x26: 0000000000000600 x25: 0000000000000000 x24: ffff8000881d7b20
[ 1626.862986] x23: ffff0000c2a981e8 x22: 1fffe00012410e7d x21: ffff0000920873e8
[ 1626.863701] x20: ffff0000920873e8 x19: ffff000086f22998 x18: 0000000000000000
[ 1626.864421] x17: 20747562202c3839 x16: 3932326636383030 x15: 3030666666662065
[ 1626.865092] x14: 6220646c756f6873 x13: 0000000000000001 x12: ffff60004fd9e4a3
[ 1626.865713] x11: 1fffe0004fd9e4a2 x10: ffff60004fd9e4a2 x9 : dfff800000000000
[ 1626.866320] x8 : 00009fffb0261b5e x7 : ffff00027ecf2513 x6 : 0000000000000001
[ 1626.866938] x5 : ffff00027ecf2510 x4 : ffff60004fd9e4a3 x3 : 0000000000000000
[ 1626.867553] x2 : 0000000000000000 x1 : ffff000096069640 x0 : 000000000000006d
[ 1626.868167] Call trace:
[ 1626.868382]  __list_del_entry_valid_or_report+0x148/0x200 (P)
[ 1626.868876]  _free_cpntf_state_locked+0xd0/0x268 [nfsd]
[ 1626.869368]  nfs4_laundromat+0x6f8/0x1058 [nfsd]
[ 1626.869813]  laundromat_main+0x24/0x60 [nfsd]
[ 1626.870231]  process_one_work+0x584/0x1050
[ 1626.870595]  worker_thread+0x4c4/0xc60
[ 1626.870893]  kthread+0x2f8/0x398
[ 1626.871146]  ret_from_fork+0x10/0x20
[ 1626.871422] Code: aa1303e1 aa1403e 910e8000 97bc55d7 (d4210000)
[ 1626.871892] SMP: stopping secondary CPUs

Reported-by: [email protected]
Closes: https://lore.kernel.org/linux-nfs/[email protected]/T/#t
Fixes: 624322f ("NFSD add COPY_NOTIFY operation")
Cc: [email protected]
Signed-off-by: Olga Kornievskaia <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>
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2 participants