1133053 - TSan: multiple data races connected to media/webrtc/signaling/src/media-conduit/RunningStat.h

Status: RESOLVED WORKSFORME

(Core :: WebRTC: Signaling, defect, P5)

Description

[Nathan Froyd [:froydnj]]

Attachment: webrtc-stat-races.txt

[cribbing from decoder's script, hopefully he won't mind]

The attached logfile shows a thread/data race detected by TSan (ThreadSanitizer).

Typically, races reported by TSan are not false positives, but it is possible that the race is benign. Even in this case though, we should try to come up with a fix unless this would cause unacceptable performance issues. Also note that seemingly benign races can possibly be harmful (also depending on the compiler and the architecture) [1].

If the bug cannot be fixed, then this bug should be used to either make a compile-time annotation for blacklisting or add an entry to the runtime blacklist.

There are multiple races in the attached file; examples could be multiplied.  I don't think these races are necessary harmful, as they appear to be gathering statistics for telemetry, but it'd be good if we could add appropriate atomic annotations or *something* for them so that TSan can understand what's going on.

[1] http://software.intel.com/en-us/blogs/2013/01/06/benign-data-races-what-could-possibly-go-wrong

Comment 1

[Bulk Bug Changes for mreavy's org]

Mass change P4->P5 to align with new Mozilla triage process.

Comment 2

[Kris Wright :KrisWright]

Webrtc signaling was moved in bug 1664900. In the new files, I can't seem to find an equivalent to these stack traces and they don't match any of our existing webrtc suppressions.