It's a low volume crash (above #300 crasher in 8.0). It happens mainly with NVIDIA drivers. Signature nsCanvasRenderingContext2DAzure::InitializeWithTarget(mozilla::gfx::DrawTarget*, int, int) UUID 6df95267-6d0b-45a6-8fcb-43e3b2111120 Date Processed 2011-11-20 12:47:03.274382 Uptime 4584 Last Crash 23.1 hours before submission Install Age 23.6 hours since version was first installed. Install Time 2011-11-19 21:11:19 Product Firefox Version 11.0a1 Build ID 20111119031209 Release Channel nightly OS Windows NT OS Version 6.1.7601 Service Pack 1 Build Architecture x86 Build Architecture Info GenuineIntel family 6 model 42 stepping 7 Crash Reason EXCEPTION_ACCESS_VIOLATION_READ Crash Address 0x0 App Notes AdapterVendorID: 10de, AdapterDeviceID: 1200, AdapterSubsysID: 15613842, AdapterDriverVersion: 8.17.12.8579 D2D? D2D+ DWrite? DWrite+ D3D10 Layers? D3D10 Layers+ Frame Module Signature [Expand] Source 0 xul.dll nsCanvasRenderingContext2DAzure::InitializeWithTarget content/canvas/src/nsCanvasRenderingContext2DAzure.cpp:1315 1 xul.dll nsCanvasRenderingContext2DAzure::SetDimensions content/canvas/src/nsCanvasRenderingContext2DAzure.cpp:1274 2 xul.dll nsHTMLCanvasElement::UpdateContext content/html/content/src/nsHTMLCanvasElement.cpp:620 3 xul.dll nsHTMLCanvasElement::GetContext content/html/content/src/nsHTMLCanvasElement.cpp:541 4 xul.dll nsIDOMHTMLCanvasElement_GetContext obj-firefox/js/xpconnect/src/dom_quickstubs.cpp:18754 5 mozjs.dll js::InvokeKernel js/src/jsinterp.cpp:629 6 mozjs.dll js::Interpret js/src/jsinterp.cpp:3950 7 mozjs.dll js::RunScript js/src/jsinterp.cpp:584 8 mozjs.dll js::InvokeKernel js/src/jsinterp.cpp:647 9 mozjs.dll js::Invoke js/src/jsinterp.cpp:679 10 mozjs.dll JS_CallFunctionValue js/src/jsapi.cpp:5223 11 xul.dll nsJSContext::CallEventHandler dom/base/nsJSEnvironment.cpp:1942 12 xul.dll nsGlobalWindow::RunTimeout dom/base/nsGlobalWindow.cpp:9311 13 xul.dll nsGlobalWindow::TimerCallback dom/base/nsGlobalWindow.cpp:9751 14 xul.dll nsTimerImpl::Fire xpcom/threads/nsTimerImpl.cpp:425 15 xul.dll nsTimerEvent::Run xpcom/threads/nsTimerImpl.cpp:521 16 xul.dll nsThread::ProcessNextEvent xpcom/threads/nsThread.cpp:631 17 xul.dll mozilla::ipc::MessagePump::Run ipc/glue/MessagePump.cpp:134 18 xul.dll xul.dll@0xbf6f8f 19 xul.dll MessageLoop::RunHandler ipc/chromium/src/base/message_loop.cc:201 20 xul.dll _SEH_epilog4 21 xul.dll MessageLoop::Run ipc/chromium/src/base/message_loop.cc:175 22 xul.dll nsThreadManager::GetCurrentThread xpcom/threads/nsThreadManager.cpp:216 23 xul.dll nsBaseAppShell::Run widget/src/xpwidgets/nsBaseAppShell.cpp:189 24 xul.dll nsAppShell::Run widget/src/windows/nsAppShell.cpp:257 More reports at: https://crash-stats.mozilla.com/report/list?range_value=4&range_unit=weeks&signature=nsCanvasRenderingContext2DAzure%3A%3AInitializeWithTarget%28mozilla%3A%3Agfx%3A%3ADrawTarget*%2C%20int%2C%20int%29

There is a spike in startup crashes from 11.0a1/20111215. The regression window for the spike is: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=fd6ab19f312c&tochange=beac16509534

Currently #8 in Top Crashers for Firefox 11.0a1.

Is that a possible cause for this crash?

This crash happens to me in 10.0.2. While I'm sure that the fix will prevent the crash, all that will happen is that getContext will start to fail. In my case, firefox will run for a few hours on a single web page (that does a fair amount of canvas operations and google maps operations) and then it crashes. goto http://pskreporter.info/pskmapn?n1dq and wait (with the page visible) and after a few hours on windows 7 it will crash. This was seen on two different systems. Yahoo toolbar not installed.