1354189 - LUL can't unwind past pthread_cond_wait

Status: RESOLVED DUPLICATE of bug 1354546

(Core :: Gecko Profiler, defect)

Description

[Markus Stange [:mstange]]

Example profile: https://perfht.ml/2p5zfLA

STR:
 1. Be on stock Ubuntu Linux, other Linux distributions probably work as well.
 2. Turn on the profiler.
 3. Navigate to https://public.etherpad-mozilla.org/p/wr-plan
 4. Take a profile.
 5. Look at the content process that's shows a lot of jank.
 6. See that the stack during most of the waiting is really short:

__pthread_unwind_next
__pthread_mutex_unlock
pthread_cond_wait
0x411bae
PRemoteSpellcheckEngine::Msg_Check
Startup::XRE_InitChildProcess
(root)

This shows that we were not able to unwind past pthread_cond_wait - we found a garbage frame "0x411bae" instead, aborted C++ stack frame unwinding, and fell back to the pseudostack.

Comment 1

[Julian Seward [:jseward]]

I think this is a sub-case of bug 1354546, and so has now been fixed.

Comment 2

[Markus Stange [:mstange]]

Confirmed, this is working now. Example profile: https://perfht.ml/2oal247

It looks like perf.html wasn't able to assign a library to the 0x40xxxx range, though, and consequently didn't symbolicate them.

Comment 3

[Markus Stange [:mstange]]

And that's because the main executable doesn't have a debugName or a breakpadId in the sharedLibraries list. Filed bug 1358360.