Julian Seward reports this crash: Program received signal SIGSEGV, Segmentation fault. __strstr_sse42 (s1=0x0, s2=0x2aaaad2cc8e6 "GLX_SGIX_fbconfig") at ../sysdeps/x86_64/multiarch/strstr.c:262 262 ../sysdeps/x86_64/multiarch/strstr.c: No such file or directory. in ../sysdeps/x86_64/multiarch/strstr.c (gdb) where #0 __strstr_sse42 (s1=0x0, s2=0x2aaaad2cc8e6 "GLX_SGIX_fbconfig") at ../sysdeps/x86_64/multiarch/strstr.c:262 #1 0x00002aaaacbbc467 in strstr (extensions=0x0, extension=0x2aaaad2cc8e6 "GLX_SGIX_fbconfig") at /usr/include/string.h:335 #2 mozilla::gl::GLContext::ListHasExtension (extensions=0x0, extension=0x2aaaad2cc8e6 "GLX_SGIX_fbconfig") at /space2/sewardj/MOZ/MC-15-11-2010/gfx/thebes/GLContext.cpp:477 #3 0x00002aaaacbd65b8 in HasExtension (this=0x2aaaadbc03e0) at /space2/sewardj/MOZ/MC-15-11-2010/gfx/thebes/GLContextProviderGLX.cpp:81 #4 mozilla::gl::GLXLibrary::EnsureInitialized (this=0x2aaaadbc03e0) at /space2/sewardj/MOZ/MC-15-11-2010/gfx/thebes/GLContextProviderGLX.cpp:185 #5 0x00002aaaacbd6894 in CreateOffscreenPixmapContext (aSize=<value optimised out>, aFormat=..., aShare=71) at /space2/sewardj/MOZ/MC-15-11-2010/gfx/thebes/GLContextProviderGLX.cpp:606 #6 0x00002aaaacbd6e36 in mozilla::gl::GLContextProviderGLX::CreateOffscreen (aSize=..., aFormat=...) at /space2/sewardj/MOZ/MC-15-11-2010/gfx/thebes/GLContextProviderGLX.cpp:715 #7 0x00002aaaabb6df11 in mozilla::WebGLContext::SetDimensions (this=0x1bcfcf0, width=300, height=150) at /space2/sewardj/MOZ/MC-15-11-2010/content/canvas/src/WebGLContext.cpp:395 #8 0x00002aaaabc0b6e5 in nsHTMLCanvasElement::UpdateContext (this=0x195e390) at /space2/sewardj/MOZ/MC-15-11-2010/content/html/content/src/nsHTMLCanvasElement.cpp:513 #9 0x00002aaaabc0bb70 in nsHTMLCanvasElement::GetContext (this=0x195e390, aContextId=..., aContext=0x7fffffffb910) at /space2/sewardj/MOZ/MC-15-11-2010/content/html/content/src/nsHTMLCanvasElement.cpp:446 #10 0x00002aaaac34b47e in nsIDOMHTMLCanvasElement_GetContext (cx=0x153ed40, argc=1, vp=0x2aaabb93f2d8) at dom_quickstubs.cpp:20967 #11 0x00002aaaace8d7fe in CallCompiler::generateNativeStub() () from /space2/sewardj/MOZ/MC-15-11-2010/ff-deb/dist/bin/libxul.so #12 0x00002aaaace8af91 in js::mjit::ic::NativeCall (f=..., ic=0x2aaaad2cc8e6) at /space2/sewardj/MOZ/MC-15-11-2010/js/src/methodjit/MonoIC.cpp:851 #13 0x00002aaac6ac87e0 in ?? ()

Comment on attachment 490857 [details] [diff] [review] fix crash with null extensions string Works for me (no more segfault), and at least OSMesa-based GL still works.

Comment on attachment 490857 [details] [diff] [review] fix crash with null extensions string This doesn't block, but let's get it in.

Sorry about that; this is definitely the result of bug 605992. I don't think we should need the null-check on extension; only on extensions.

http://hg.mozilla.org/mozilla-central/rev/789f0f85f75a David, I saw your comment too late, sorry. At least it doesn't hurt to check |extension| too even if that's useless. It's true that to fix this particular crash it was enough to check |extensions|.