1189197 - Race in bufferqueue_callback (cubeb_opensl.c)

Status: RESOLVED FIXED

(Core :: Audio/Video: MediaStreamGraph, defect)

Description

[JW Wang [:jwwang] [:jw_wang]]

This bug is explored by bug 1187817 (see bug 1187817 comment 18).

When opensl_stream_start is called, it is possible bufferqueue_callback is still in progress. Since opensl_stream_start calls bufferqueue_callback, bufferqueue_callback (which is not reentrant) will be entered from 2 threads and cause errors.

See bug 1187817 comment 19 ~ bug 1187817 comment 24 for more details.

Comment 1

[JW Wang [:jwwang] [:jw_wang]]

Attachment: 1189197_fix_bufferqueue_callback_reentrant-v1.patch

Comment 2

[JW Wang [:jwwang] [:jw_wang]]

The only problem left is, do we need to enqueue a silent frame each time resuming playback? I think not.

https://hg.mozilla.org/mozilla-central/file/2ddec2dedced/media/libcubeb/src/cubeb_opensl.c#l111

bufferqueue_callback ensure there is always at least one buffer in the queue. So whenever playback is resumed, there will always be a buffer to be consumed to kick off the buffer queue callback.

Comment 3

[JW Wang [:jwwang] [:jw_wang]]

Try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=4702f53c1e4e

Comment 4

[Matthew Gregan [:kinetik]]

Comment on attachment 8641462 [details] [diff] [review]
1189197_fix_bufferqueue_callback_reentrant-v1.patch

Review of attachment 8641462 [details] [diff] [review]:
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Thanks, let's give this a shot!

Comment 5

[JW Wang [:jwwang] [:jw_wang]]

Thanks for the review!

Comment 6

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/692828b8e47a

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/692828b8e47a