980109 - ScopedXPCOM leaks tlsPseudoStack through shutdown

Status: RESOLVED DUPLICATE of bug 1047124

(Core :: Gecko Profiler, defect)

Description

[Andrew McCreight [:mccr8]]

A stack like this shows up many times when the CPP unit tests are run with LSAN:

==2654==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 32856 byte(s) in 1 object(s) allocated from:
    #0 0x4463f5 in __interceptor_malloc /builds/slave/moz-toolchain/src/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:74
    #1 0x7f4a408aab18 in moz_xmalloc /somedir/memory/mozalloc/mozalloc.cpp:52
    #2 0x7f4a41bd9ba3 in profiler_init /somedir/obj-firefox/xpcom/build/../../dist/include/GeckoProfilerImpl.h:59
    #3 0x7f4a41bd9ba3 in NS_InitXPCOM2 /somedir/xpcom/build/nsXPComInit.cpp:406
    #4 0x45ae11 in ScopedXPCOM /somedir/xpcom/tests/TestHarness.h:110
    #5 0x45ae11 in ScopedXPCOM /somedir/xpcom/tests/TestHarness.h:117
    #6 0x45ae11 in main /somedir/xpcom/tests/TestDeque.cpp:233
    #7 0x7f4a3f24976c (/lib/x86_64-linux-gnu/libc.so.6+0x2176c)
SUMMARY: LeakSanitizer: 32856 byte(s) leaked in 1 allocation(s).

I'm guessing this is the allocation of the pseudostack in mozilla_sampler_init, and that ScopedXPCOM is missing a matching call to profiler_shutdown().  This doesn't seem like a real issue, but it would be nice to clear out a bit of noise if the fix is easy.  If not, I can add this to the suppression list.

Comment 1

[Andrew McCreight [:mccr8]]

Oh maybe this explains it (from the end of  mozilla_sampler_shutdown):
548   // We can't delete the Stack because we can be between a
549   // sampler call_enter/call_exit point.
550   // TODO Need to find a safe time to delete Stack

Suppression list it is, I guess.

Comment 2

[Benoit Girard (:BenWa)]

It's not impossible but not easy. I admit I do hate introducing this kind of noise :(.

Comment 3

[Andrew McCreight [:mccr8]]

Hooray!  Bug 1047124 fixed the leak and removed the suppression.