1764999 - Crash in [@ mozilla::WebGLContext::LruPosition::reset]

Status: RESOLVED DUPLICATE of bug 1769739

(Core :: Graphics: CanvasWebGL, defect)

Description

[Andrew Osmond [:aosmond] (he/him)]

Maybe Fission related. (DOMFissionEnabled=1)

Crash report: https://crash-stats.mozilla.org/report/index/777365fd-bb91-4ce6-82f1-9cc4b0220414

Reason: EXCEPTION_ACCESS_VIOLATION_READ

Top 10 frames of crashing thread:

0 xul.dll mozilla::WebGLContext::LruPosition::reset dom/canvas/WebGLContext.cpp:129
1 xul.dll mozilla::WebGLContext::BumpLru dom/canvas/WebGLContext.h:275
2 xul.dll mozilla::WebGLContext::PresentInto dom/canvas/WebGLContext.cpp:871
3 xul.dll mozilla::WebGLContext::Present dom/canvas/WebGLContext.cpp:982
4 xul.dll mozilla::HostWebGLContext::Present const dom/canvas/HostWebGLContext.h:173
5 xul.dll mozilla::ClientWebGLContext::Run<void  const dom/canvas/ClientWebGLContext.cpp:351
6 xul.dll mozilla::ClientWebGLContext::Present dom/canvas/ClientWebGLContext.cpp:407
7 xul.dll mozilla::ClientWebGLContext::PresentFrontBuffer dom/canvas/ClientWebGLContext.cpp:441
8 xul.dll mozilla::dom::OffscreenCanvasDisplayHelper::CommitFrameToCompositor dom/canvas/OffscreenCanvasDisplayHelper.cpp:115
9 xul.dll mozilla::dom::OffscreenCanvas::DequeueCommitToCompositor dom/canvas/OffscreenCanvas.cpp:219

We appear to be accessing a global without a mutex on multiple threads:

https://searchfox.org/mozilla-central/rev/d34f9713ae128a3138c2b70d8041a535f1049d19/dom/canvas/WebGLContext.cpp#119

Comment 1

[Andrew Osmond [:aosmond] (he/him)]

I think I dismissed this initially because I thought it would be accessed only in the parent process.