Shih-Chiang Chien f3b944c4e8 Bug 1426751 - Prevent FlushQueue to be invoked on multiple threads simultaneously. r=mayhemer ...

This issue is triggered by off-main-thread ODA listener that return error cause from OnDataAvailable callback.
A CancelEvent will be prepend to event queue and trigger race condition between CompleteResume and EndForceEnqueueing.

The `mFlushing` is checked and set in separate critical sections, therefore two threads that executing MayFlushQueue
might both pass the `mFlushing` check and trying to call FlushQueue simultaneously.

The solution is to check and set `mFlushing` in single critical section, so we can guarantee that only one FlushQueue
can be executed at anytime.

In addition, resumption is postponed until no AutoEventEnqueuer is activated. Therefore, CompleteResume will only be
triggered while all the suspension requests and auto enqueue requests are finished.

MozReview-Commit-ID: HpxzgUqYm8C

2018-01-04 18:53:02 +08:00

4.6 KiB

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