On WINNT 5.2 mozilla-central debug test mochitests-5/5 the following is happening: NEXT ERROR TEST-UNEXPECTED-FAIL | /tests/toolkit/content/tests/widgets/test_bug360220.xul | Exited with code -1073741819 during test run INFO | automation.py | Application ran for: 0:12:05.891000 INFO | automation.py | Reading PID log: c:\docume~1\cltbld\locals~1\temp\tmpctrs5spidlog PROCESS-CRASH | /tests/toolkit/content/tests/widgets/test_bug360220.xul | application crashed (minidump found) Operating system: Windows NT 5.2.3790 Service Pack 2 CPU: x86 GenuineIntel family 6 model 15 stepping 8 1 CPU Crash reason: EXCEPTION_ACCESS_VIOLATION Crash address: 0x0 Thread 0 (crashed) 0 xul.dll!JS_Assert [jsutil.cpp:ca371593d433 : 73 + 0x0] eip = 0x11547c7a esp = 0x0012cb58 ebp = 0x0012cb58 ebx = 0x00000000 esi = 0x012e2798 edi = 0x00000000 eax = 0x00000000 ecx = 0x672a9bd7 edx = 0x003a1d40 efl = 0x00010202 Found by: given as instruction pointer in context See http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1283858419.1283859581.4012.gz

A "crash" in JS_Assert tends to actually be "the js assert above was fatal".