845504 - TSan: Thread data race in makewt_32(void) vs. cftmdl_128_SSE2(float *a)

Status: RESOLVED WORKSFORME

(Core :: WebRTC, defect, P3)

Description

[Christoph Diehl [:posidron]]

Attachment: trace

During initial tests with ThreadSanitizer (LLVM version), we get a data race reported as described in the attached log. Trace was created on mozilla-central with changeset 122820:c233837cce08.

According to the TSan devs, most of the reported traces should be real data races, even though they can be "benign". We need to determine if the race can/should be fixed, or put on the ignore list. Even for benign races, TSan devs suggest to fix them (second priority), as they can also cause problems [1].

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

Comment 1

[Randell Jesup [:jesup] (needinfo me)]

Race on access to cftmdl_wk1r - in this case, something is reading it in AEC processing before it gets inited in WebRtcAec_InitAec().  Upstream issue 1503
https://code.google.com/p/webrtc/issues/detail?id=1503

Not sure if FF21 is affected.

Impact would likely be temporary AEC mis-training/worked at start, if this were to actually occue.

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

Not sure about blocking yet

Comment 3

[Randell Jesup [:jesup] (needinfo me)]

Blocking- since I think the worst case here (which is unlikely in practice) would be a mis-initialization or failure of the AEC

Comment 4

[Randell Jesup [:jesup] (needinfo me)]

this appears to be audio sample insertion racing against enabling of the AEC.  It shouldn't be a suppressed TSAN hit, it should avoid trying to run the AEC before init is finished.

Comment 5

[Bulk Bug Changes for mreavy's org]

Mass change P2->P3 to align with new Mozilla triage process.

Comment 6

[Tom Ritter [:tjr]]

Clearing sec-want based on C3

Comment 7

[Aria Beingessner [:Gankra]]

This was fixed upstream 8 years ago, and it appears we have since uplifted the fixes (or otherwise made this irrelevant).