1527453 - Examine IOInterposer thread safety

Status: NEW

(Core :: Gecko Profiler, enhancement, P2)

Description

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

IOInterposer is probably effectively only used from the main thread (aka MT), but the profiler code currently allows for the possibility of being used off-MT, and with bug 1526357 it is now possible that it could be unregistered before the profiler shuts down (while other IO operations may still happen.)

In particular sMasterList is accessed from most methods without any atomicity nor locking.

So I think we should review the thread safety around IOInterposer, and either add checks to verify that it's always called from one thread, or add proper thread safety.

Comment 1

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Could be useful to profile startup, now that most main-thread IOs have been taken care of.