It's #13 top crasher in Fennec 11.0a1. It first appeared in 10.0a1/20110928. The regression range might be: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1f800c226837&tochange=7f4867717226 The stack trace looks like: Frame Module Signature [Expand] Source 0 libc.so libc.so@0x135a8 1 libc.so libc.so@0x14747 2 libstdc++.so _ZdlPv 3 libxul.so TOutputESSL::writeVariablePrecision _new.h:135 4 libxul.so TOutputGLSLBase::writeVariableType gfx/angle/src/compiler/OutputGLSLBase.cpp:123 5 libxul.so TOutputGLSLBase::visitAggregate gfx/angle/src/compiler/OutputGLSLBase.cpp:540 6 libxul.so TIntermAggregate::traverse gfx/angle/src/compiler/IntermTraverse.cpp:135 7 libxul.so TOutputGLSLBase::visitAggregate gfx/angle/src/compiler/OutputGLSLBase.cpp:454 8 libxul.so TIntermAggregate::traverse gfx/angle/src/compiler/IntermTraverse.cpp:135 9 libxul.so TranslatorESSL::translate gfx/angle/src/compiler/TranslatorESSL.cpp:27 10 libxul.so TCompiler::compile gfx/angle/src/compiler/Compiler.cpp:182 11 libxul.so ShCompile gfx/angle/src/compiler/ShaderLang.cpp:186 12 libxul.so mozilla::WebGLContext::CompileShader content/canvas/src/WebGLContextGL.cpp:4486 13 libxul.so nsIDOMWebGLRenderingContext_CompileShader obj-firefox/js/xpconnect/src/dom_quickstubs.cpp:23849 14 libxul.so js::InvokeKernel js/src/jscntxtinlines.h:297 15 libxul.so js::Interpret js/src/jsinterp.cpp:3729 16 libxul.so js::RunScript js/src/jsinterp.cpp:580 17 libxul.so js::Invoke js/src/jsinterp.cpp:643 18 libxul.so JS_CallFunctionValue js/src/jsapi.cpp:5186 More crash reports at: https://crash-stats.mozilla.com/report/list?range_value=30&range_unit=days&signature=_ZdlPv