Bug 30353

Summary:

[GStreamer] Race condition causing deadlocks

Product:

WebKit

Reporter:

Sebastian Dröge (slomo) <slomo>

Component:

Media

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

commit-queue, pnormand

Priority:

Version:

528+ (Nightly build)

Hardware:

OS:

Linux

Attachments:

Description	Flags
0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch	gustavo: review-
Stacktrace showing the deadlock	none
0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch	none

Sebastian Dröge (slomo)

Reported 2009-10-14 04:19:21 PDT

Hi, currently there's a race condition in the GStreamer video sink. Problem is, if unlock() is called and then render(). It would wait forever on the cond. Attached patch fixes this.

Attachments
0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch (5.11 KB, patch) 2009-10-14 04:24 PDT, Sebastian Dröge (slomo)	gustavo: review-	Details Formatted Diff Diff
Stacktrace showing the deadlock (6.31 KB, text/plain) 2009-10-14 04:27 PDT, Benjamin Otte	no flags	Details
0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch (5.53 KB, patch) 2009-10-15 06:57 PDT, Sebastian Dröge (slomo)	no flags	Details Formatted Diff Diff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.

Sebastian Dröge (slomo)

Comment 1 2009-10-14 04:24:53 PDT

Created attachment 41156 [details] 0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch

Benjamin Otte

Comment 2 2009-10-14 04:27:34 PDT

Created attachment 41157 [details] Stacktrace showing the deadlock

Gustavo Noronha (kov)

Comment 3 2009-10-15 06:46:19 PDT

Comment on attachment 41156 [details] 0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch Man, threading is hairy =). So, what's causing the deadlock, exactly, again? The cond_wait in render and the mutex_lock in timeout_func racing when gstreamer fires ::unlock? Then you fix it by avoiding creating the timeout and doing the cond_wait in the first place if ::unlock() has fired on the element, is that it? Can you add a comment block somewhere explaining this?

Sebastian Dröge (slomo)

Comment 4 2009-10-15 06:57:43 PDT

Created attachment 41223 [details] 0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch

Gustavo Noronha (kov)

Comment 5 2009-10-15 07:01:05 PDT

Comment on attachment 41223 [details] 0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch Thanks!

WebKit Commit Bot

Comment 6 2009-10-15 07:16:33 PDT

Comment on attachment 41223 [details] 0001-Fix-race-condition-in-unlock-render-that-would-lead-.patch Clearing flags on attachment: 41223 Committed r49623: <http://trac.webkit.org/changeset/49623>

WebKit Commit Bot

Comment 7 2009-10-15 07:16:36 PDT

All reviewed patches have been landed. Closing bug.

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