With a patch I wrote that intentionally crashes in jemalloc, the Jetpack test suite does not produce a useful crash stack: Hit MOZ_CRASH() at /builds/slave/try-l64-d-00000000000000000000/build/memory/mozjemalloc/jemalloc.c:1572 Program firefox/firefox-bin (pid = 1790) received signal 11. Stack: UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x026686AE] UNKNOWN [/lib/x86_64-linux-gnu/libpthread.so.0 +0x0000FCB0] UNKNOWN [firefox/firefox-bin +0x0001467B] UNKNOWN [firefox/firefox-bin +0x00018055] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x0095D3A3] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x022A2641] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x022A2F50] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x022A43BE] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x02174062] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x009C96C9] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x00AC8805] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x009B1622] UNKNOWN [/builds/slave/test/build/firefox/libxul.so +0x0092595A] Presumably this isn't a big deal mostly, because other tests should catch libxul crashes, but I thought I'd file it anyways. (This doesn't affect me because I wrote a patch that just crashes everywhere, so this is presumably an instance of that other issue.)