1290199 - MOZ_PROFILER_SHUTDOWN crash with mPseudoStack when saving the profile

Status: RESOLVED WORKSFORME

(Core :: Gecko Profiler, defect)

Description

[Benoit Girard (:BenWa)]

~/mozilla/mozilla-central/tree> MOZ_PROFILER_STARTUP=true MOZ_PROFILER_SHUTDOWN=prof.dat ./mach run --debug
 0:01.69 /Applications/Xcode.app/Contents/Developer/usr/bin/lldb -- /Users/bgirard/mozilla/mozilla-central/builds/obj-ff-64gdb/dist/Nightly.app/Contents/MacOS/firefox -no-remote -foreground -profile /Users/bgirard/mozilla/mozilla-central/builds/obj-ff-64gdb/tmp/scratch_user
There is a .lldbinit file in the current directory which is not being read.
To silence this warning without sourcing in the local .lldbinit,
add the following to the lldbinit file in your home directory:
    settings set target.load-cwd-lldbinit false
To allow lldb to source .lldbinit files in the current working directory,
set the value of this variable to true.  Only do so if you understand and
accept the security risk.
(lldb) target create "/Users/bgirard/mozilla/mozilla-central/builds/obj-ff-64gdb/dist/Nightly.app/Contents/MacOS/firefox"
Current executable set to '/Users/bgirard/mozilla/mozilla-central/builds/obj-ff-64gdb/dist/Nightly.app/Contents/MacOS/firefox' (x86_64).
(lldb) settings set -- target.run-args  "-no-remote" "-foreground" "-profile" "/Users/bgirard/mozilla/mozilla-central/builds/obj-ff-64gdb/tmp/scratch_user"
(lldb) process launch
Process 55614 launched: '/Users/bgirard/mozilla/mozilla-central/builds/obj-ff-64gdb/dist/Nightly.app/Contents/MacOS/firefox' (x86_64)
Process 55614 stopped
* thread #1: tid = 0x3645b, 0x0000000104cfa6f2 XUL`ThreadProfile::StreamJSON(SpliceableJSONWriter&, double) [inlined] void mozilla::Maybe<UniqueStacks>::emplace<JSRuntime*&>(JSRuntime*&&&) + 4 at Maybe.h:390, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x6030)
    frame #0: 0x0000000104cfa6f2 XUL`ThreadProfile::StreamJSON(SpliceableJSONWriter&, double) [inlined] void mozilla::Maybe<UniqueStacks>::emplace<JSRuntime*&>(JSRuntime*&&&) + 4 at Maybe.h:390
   387 	  void emplace(Args&&... aArgs)
   388 	  {
   389 	    MOZ_ASSERT(!mIsSome);
-> 390 	    ::new (mStorage.addr()) T(Forward<Args>(aArgs)...);
   391 	    mIsSome = true;
   392 	  }
   393 	};
(lldb) up
frame #1: 0x0000000104cfa6ee XUL`ThreadProfile::StreamJSON(this=0x00000001155bd000, aWriter=0x00007fff5fbfed80, aSinceTime=0) + 62 at ThreadProfile.cpp:51
   48  	  // mUniqueStacks may already be emplaced from FlushSamplesAndMarkers.
   49  	  if (!mUniqueStacks.isSome()) {
   50  	#ifndef SPS_STANDALONE
-> 51  	    mUniqueStacks.emplace(mPseudoStack->mRuntime);
   52  	#else
   53  	    mUniqueStacks.emplace(nullptr);
   54  	#endif
(lldb) print mPseudoStack
(PseudoStack *) $0 = 0x0000000000000000

Comment 1

[Markus Stange [:mstange]]

I cannot reproduce this. And looking at the code, it looks like we've changed things so that mPseudoStack is never null here.