1937908 - Assertion failure: !mProcess in GMPParent::~GMPParent during shutdown

Status: RESOLVED FIXED

(Core :: Audio/Video: GMP, defect, P2)

Description

[Andreas Pehrson [:pehrsons]]

Attachment: stdout with MOZ_LOG=GMP:5

My STR was to send a high-res screen capture over WebRTC using OpenH264, then observe the encoder latency going up and shut down Firefox when the encoder latency is >1s. Intermittently it would trip this assertion.

Comment 1

[Andreas Pehrson [:pehrsons]]

I'll note I reproduced this with only the fix for bug 1937731 applied, as well as with the fixes for both bug 1937731 and bug 1936275 applied. The attached log was captured with both bugs applied.

Comment 2

[Andreas Pehrson [:pehrsons]]

I see this comment "Normal Shutdown() will delete the process on unwind", but fail to see how that could work with the dtor assert, or what exactly is meant by "unwind".

Comment 3

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1937908 - Revert changeset d75ea9fa6cda. r?aosmond

It only partially wallpapered over a problem.
Subsequent commits will fix it better.

Comment 4

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1937908 - Remove undefined function GMPParent::AbortAsyncShutdown. r?aosmond

Comment 5

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1937908 - Move GMPServiceChild to ShutdownBlockingTicket. r?aosmond

Comment 6

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1937908 - Move GMPServiceParent to ShutdownBlockingTicket and make members const. r?aosmond

Comment 7

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1937908 - Block shutdown in GMPProcessParent. r?aosmond

There is a shutdown race that can happen in GMPParent.
On ActorDestroy(NormalShutdown), if the GMP process is backlogged with work, it
may not yet have shut down. At the same time, ActorDestroy(NormalShutdown)
happens after xpcom-shutdown-threads, which has made sure to shut down the GMP
event target in GMPService. The graceful shutdown of the GMP process requires
dispatching tasks to the GMP event target (see GMPParent::DeleteProcess), which,
if the target has been shut down, will result in the GMP process leaking because
the SendShutdown Then handler could not be dispatched. If it even gets that far.

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/866fa8510165
Revert changeset d75ea9fa6cda. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/1cf5ffd4299a
Remove undefined function GMPParent::AbortAsyncShutdown. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/f0b7d22731bc
Move GMPServiceChild to ShutdownBlockingTicket. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/4723190b3ae4
Move GMPServiceParent to ShutdownBlockingTicket and make members const. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/de6301e43b81
Block shutdown in GMPProcessParent. r=aosmond,media-playback-reviewers

Comment 9

[amarc]

Backed out for causing build bustages @ GMPParent.cpp

• Backout link
• Push with failures
• Failure Log
• Failure line:

/builds/worker/checkouts/gecko/dom/media/gmp/GMPParent.cpp:63:17: error: format '%u' expects argument of type 'unsigned int', but argument 8 has type 'mozilla::gmp::GMPState' [-Werror=format=]

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a798ca03e4bd
Revert changeset d75ea9fa6cda. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/c96513264f3d
Remove undefined function GMPParent::AbortAsyncShutdown. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/fbd159562f11
Move GMPServiceChild to ShutdownBlockingTicket. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/cb89d984064e
Move GMPServiceParent to ShutdownBlockingTicket and make members const. r=aosmond,media-playback-reviewers
https://hg.mozilla.org/integration/autoland/rev/ade69911a87b
Block shutdown in GMPProcessParent. r=aosmond,media-playback-reviewers

Comment 11

[amarc]

https://hg.mozilla.org/mozilla-central/rev/a798ca03e4bd
https://hg.mozilla.org/mozilla-central/rev/c96513264f3d
https://hg.mozilla.org/mozilla-central/rev/fbd159562f11
https://hg.mozilla.org/mozilla-central/rev/cb89d984064e
https://hg.mozilla.org/mozilla-central/rev/ade69911a87b