920098 - Potential profiler deadlock on MacOS

Status: RESOLVED DUPLICATE of bug 1054335

(Core :: Gecko Profiler, defect)

Description

[(No longer employed by Mozilla) Aaron Klotz]

There's a potential deadlock that could occur under the right conditions in any profiler_lock or profiler_stop invocation.

1. SamplerThread calls SamplerRegistry::sampler->IsActive(), it returns true
2. Sampler::Stop called on another thread, active_ is changed to false.
3. Thread calling Sampler::Stop takes sRegisteredThreadsMutex
4. Thread calling Sampler::Stop then joins on the SamplerThread
5. SamplerThread tries to take sRegisteredThreadsMutex, blocks, we deadlock.

This can't happen on Linux or Win32 because step 3 doesn't happen on those platforms.

Comment 1

[(No longer employed by Mozilla) Aaron Klotz]

Marking as dup of bug 1054335 since that bug's description is more in line with the current state of the code.