Closed Bug 1652174 Opened 2 months ago Closed 2 months ago

ThreadSanitizer: data race [@ event_base_loop] vs [@ event_set]

Categories

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

defect

Tracking

()

RESOLVED FIXED
mozilla80
Tracking Status
firefox80 --- fixed

People

(Reporter: bwc, Assigned: bwc)

References

(Blocks 2 open bugs)

Details

Attachments

(2 files)

Attached file tsan output

If true, this looks like a flaw down in libevent. However, it may also be because TSan does not grok fences. Saw this when running webrtc mochitests under TSan. Marking security for now, until we can determine whether this is a real flaw or not.

Which tests exactly did you run for this? We already run Mochitests in CI for TSan and I haven't seen this one before.

Group: core-security → media-core-security

(In reply to Christian Holler (:decoder) from comment #1)

Which tests exactly did you run for this? We already run Mochitests in CI for TSan and I haven't seen this one before.

This happens on the webrtc mochitests, which are part of the "mda" mochitest suite (which has no TSan jobs right now, see bug 1648192). It also happens in the webrtc web-platform-tests.

Looks like this is due to this flag:

https://searchfox.org/mozilla-central/rev/1b95a0179507a4dc7d4b0c94c2df420dc1a72885/ipc/chromium/src/third_party/libevent/event.c#251

Probably makes sense to suppress, but is kinda difficult because this flag is touched in macros all over the place.

There is a bug open on libevent: https://github.com/libevent/libevent/issues/777

Assignee: nobody → docfaraday

Can you clear the sec flag on this, it looks pretty much benign to me?

Flags: needinfo?(dveditz)
Group: media-core-security
Flags: needinfo?(dveditz)
Component: WebRTC: Audio/Video → IPC

So, I'm not sure this manifests in our IPC code. I have only seen this down in webrtc.org, which also uses libevent.

Component: IPC → WebRTC: Audio/Video
Pushed by bcampen@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/daf7d1c828c5
Suppress TSan race error in libevent's event_debug_mode_too_late r=dminor
Status: NEW → RESOLVED
Closed: 2 months ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla80
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