Can't help but notice that this happened shortly after bug 407059 landed on inbound. https://tbpl.mozilla.org/php/getParsedLog.php?id=38332938&tree=Mozilla-Inbound Windows 7 32-bit mozilla-inbound opt test reftest-no-accel on 2014-04-23 08:55:10 PDT for push 32616a509bed slave: t-w732-ix-094 09:10:40 INFO - REFTEST TEST-START | file:///C:/slave/test/build/tests/reftest/tests/layout/reftests/mathml/opentype-stretchy.html 09:10:40 INFO - REFTEST TEST-LOAD | file:///C:/slave/test/build/tests/reftest/tests/layout/reftests/mathml/opentype-stretchy.html | 6198 / 10892 (56%) 09:10:40 INFO - ??????????????????????????: TREFTEST TEST-LOAD | file:///C:/slave/test/build/tests/reftest/tests/layout/reftests/mathml/opentype-stretchy-ref.html | 6198 / 10892 (56%) 09:10:42 INFO - TEST-INFO | Main app process: exit status c0000005 09:10:42 WARNING - TEST-UNEXPECTED-FAIL | file:///C:/slave/test/build/tests/reftest/tests/layout/reftests/mathml/opentype-stretchy.html | Exited with code -1073741819 during test run 09:10:42 INFO - INFO | automation.py | Application ran for: 0:10:40.797000 09:10:42 INFO - INFO | zombiecheck | Reading PID log: c:\users\cltbld\appdata\local\temp\tmphl9uwgpidlog 09:10:42 INFO - ==> process 4024 launched child process 3856 ("C:\slave\test\build\application\firefox\plugin-container.exe" --channel=4024.12c2fef0.2003092643 "c:\users\cltbld\appdata\local\temp\tmp7hhixf.mozrunner\plugins\nptest.dll" -greomni "C:\slave\test\build\application\firefox\omni.ja" -appomni "C:\slave\test\build\application\firefox\browser\omni.ja" -appdir "C:\slave\test\build\application\firefox\browser" - 4024 "\\.\pipe\gecko-crash-server-pipe.4024" plugin) 09:10:42 INFO - mozcrash INFO | Downloading symbols from: https://ftp-ssl.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-inbound-win32/1398264242/firefox-31.0a1.en-US.win32.crashreporter-symbols.zip 09:10:48 WARNING - PROCESS-CRASH | file:///C:/slave/test/build/tests/reftest/tests/layout/reftests/mathml/opentype-stretchy.html | application crashed [@ _cairo_dwrite_font_face_scaled_font_create] 09:10:48 INFO - Crash dump filename: c:\users\cltbld\appdata\local\temp\tmp7hhixf.mozrunner\minidumps\8a5d61ab-e7b1-4792-bdae-9d292dabaf5b.dmp 09:10:48 INFO - Operating system: Windows NT 09:10:48 INFO - 6.1.7601 Service Pack 1 09:10:48 INFO - CPU: x86 09:10:48 INFO - GenuineIntel family 6 model 30 stepping 5 09:10:48 INFO - 8 CPUs 09:10:48 INFO - Crash reason: EXCEPTION_ACCESS_VIOLATION_READ 09:10:48 INFO - Crash address: 0x5a5a5a5a 09:10:48 INFO - Thread 0 (crashed) 09:10:48 INFO - 0 gkmedias.dll!_cairo_dwrite_font_face_scaled_font_create [cairo-dwrite-font.cpp:32616a509bed : 510 + 0x38] 09:10:48 INFO - eip = 0x669d55ac esp = 0x0024c49c ebp = 0x0024c518 ebx = 0x12d18400 09:10:48 INFO - esi = 0x5a5a5a5a edi = 0x0024c558 eax = 0x00000000 ecx = 0x3541e218 09:10:48 INFO - edx = 0x00020001 efl = 0x00210246 09:10:48 INFO - Found by: given as instruction pointer in context 09:10:48 INFO - 1 gkmedias.dll!_moz_cairo_scaled_font_create [cairo-scaled-font.c:32616a509bed : 1054 + 0x1a] 09:10:48 INFO - eip = 0x669c94d7 esp = 0x0024c520 ebp = 0x0024c700 09:10:48 INFO - Found by: call frame info 09:10:48 INFO - 2 gkmedias.dll!_cairo_gstate_ensure_scaled_font [cairo-gstate.c:32616a509bed : 1811 + 0x16] 09:10:48 INFO - eip = 0x669b5437 esp = 0x0024c708 ebp = 0x0024c74c 09:10:48 INFO - Found by: call frame info 09:10:48 INFO - 3 gkmedias.dll!_cairo_gstate_get_scaled_font [cairo-gstate.c:32616a509bed : 1685 + 0x9] 09:10:48 INFO - eip = 0x669b98d1 esp = 0x0024c754 ebp = 0x0024c758 09:10:48 INFO - Found by: call frame info 09:10:48 INFO - 4 gkmedias.dll!_moz_cairo_get_scaled_font [cairo.c:32616a509bed : 3265 + 0xb] 09:10:48 INFO - eip = 0x669d4aab esp = 0x0024c760 ebp = 0x0024c770 09:10:48 INFO - Found by: call frame info 09:10:48 INFO - 5 xul.dll!DCFromContext::DCFromContext(gfxContext *) [gfxWindowsPlatform.h:32616a509bed : 72 + 0xd] 09:10:48 INFO - eip = 0x65481aa9 esp = 0x0024c778 ebp = 0x0024c790 09:10:48 INFO - Found by: call frame info 09:10:48 INFO - 6 xul.dll!gfxGDIFont::GetGlyphWidth(gfxContext *,unsigned short) [gfxGDIFont.cpp:32616a509bed : 552 + 0xa] 09:10:48 INFO - eip = 0x654827df esp = 0x0024c798 ebp = 0x0024c7c4 09:10:48 INFO - Found by: call frame info 09:10:48 INFO - 7 xul.dll!gfxFont::GetGlyphHAdvance(gfxContext *,unsigned short) [gfxFont.cpp:32616a509bed : 2035 + 0xc] 09:10:48 INFO - eip = 0x654922fe esp = 0x0024c7cc ebp = 0x0024c7d8 09:10:48 INFO - Found by: call frame info 09:10:48 INFO - 8 xul.dll!nsOpenTypeTable::MakeTextRun(gfxContext *,int,gfxFontGroup *,nsGlyphCode const &) [nsMathMLChar.cpp:32616a509bed : 548 + 0x15] 09:10:48 INFO - eip = 0x65d71b53 esp = 0x0024c7e0 ebp = 0x0024c82c 09:10:48 INFO - Found by: call frame info

From the crash log, it looks like !SetupCairoFont(aCtx) should be called before GetGlyphWidth(aCtx, aGID) too... I'll upload a patch.

Comment on attachment 8411216 [details] [diff] [review] Patch Review of attachment 8411216 [details] [diff] [review]: ----------------------------------------------------------------- Yes - seeing _cairo_dwrite_font_face_scaled_font_create on the stack when it's a reftest-no-accel run (which should use GDI fonts) looks like a smoking gun indicating that the font hadn't been initialized yet. So this should fix it.

Thanks for the quick patch! https://hg.mozilla.org/integration/mozilla-inbound/rev/3202a3687c0a