runtime/race: invalid spdelta tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy

[bradfitz]

Weird trybot failure in tsan:

https://storage.googleapis.com/go-build-log/78af9465/linux-amd64-race_91e55cda.log

--- FAIL: TestStackBarrierProfiling (4.60s)
    pprof_test.go:342: subprocess failed with signal: segmentation fault:
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a5307 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a5307 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a5307 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a530f 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a530f 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a530f 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a5304 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a5307 0x0 -1
        invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x5a5270 0x5a5304 0x0 -1
FAIL
FAIL    runtime/pprof   13.799s
2015/12/10 18:38:36 Failed: exit status 1

/cc @aclements

[rsc]

I think that's the stack unwinder trying to unwind through TSAN during a profiling signal, which it should not. Looks like the linker is not writing down "I don't have information" correctly, or else the runtime is not recognizing it.

[dvyukov]

I was able to reproduce it once in 1000 runs, using stress ./pprof.test -test.short:

--- FAIL: TestStackBarrierProfiling (1.16s)
pprof_test.go:342: subprocess failed with signal: segmentation fault (core dumped):
invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x59e850 0x59e8e7 0x0 -1
invalid spdelta _ZN6__tsanL14MemoryRangeSetEPNS_11ThreadStateEmmmy.isra.32.part.33 0x59e850 0x59e8e4 0x0 -1
FAIL

It took more than an hour.

[gopherbot]

CL https://golang.org/cl/18322 mentions this issue.