Filed by: nbeleuzu [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=314330928&repo=autoland
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/OlG1ksiRQw-Y5CtKfE0NTw/runs/0/artifacts/public/logs/live_backing.log

[task 2020-08-28T22:56:02.770Z] 22:56:02 INFO - PROCESS-CRASH | Main app process exited normally | application crashed [@ mozilla::LinkedList<js::ParseTask>::~LinkedList()]
[task 2020-08-28T22:56:02.770Z] 22:56:02 INFO - Crash dump filename: /tmp/tmpja2k3s.mozrunner/minidumps/6e023856-7a7d-d3df-c939-9d5f01c32a56.dmp
[task 2020-08-28T22:56:02.770Z] 22:56:02 INFO - Operating system: Linux
[task 2020-08-28T22:56:02.771Z] 22:56:02 INFO - 0.0.0 Linux 4.4.0-1014-aws #14taskcluster1-Ubuntu SMP Tue Apr 3 10:27:00 UTC 2018 x86_64
[task 2020-08-28T22:56:02.771Z] 22:56:02 INFO - CPU: amd64
[task 2020-08-28T22:56:02.771Z] 22:56:02 INFO - family 6 model 85 stepping 7
[task 2020-08-28T22:56:02.771Z] 22:56:02 INFO - 2 CPUs
[task 2020-08-28T22:56:02.772Z] 22:56:02 INFO -
[task 2020-08-28T22:56:02.772Z] 22:56:02 INFO - GPU: UNKNOWN
[task 2020-08-28T22:56:02.773Z] 22:56:02 INFO -
[task 2020-08-28T22:56:02.773Z] 22:56:02 INFO - Crash reason: SIGSEGV /SEGV_MAPERR
[task 2020-08-28T22:56:02.773Z] 22:56:02 INFO - Crash address: 0x0
[task 2020-08-28T22:56:02.773Z] 22:56:02 INFO - Process uptime: not available
[task 2020-08-28T22:56:02.773Z] 22:56:02 INFO -
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - Thread 0 (crashed)
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - 0 libxul.so!mozilla::LinkedList<js::ParseTask>::~LinkedList() [LinkedList.h:226ed0ce4e27275652ae247d5090f82d49b58445 : 439 + 0x36]
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - rax = 0x0000561c20aace68 rdx = 0x0000000000000000
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - rcx = 0x0000000000000b40 rbx = 0x0000561c20aace70
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - rsi = 0x00007f17a18988b0 rdi = 0x00007f17a1897680
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - rbp = 0x00007ffcc19ac960 rsp = 0x00007ffcc19ac950
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - r8 = 0x00007f17a18988b0 r9 = 0x00007f17a2793780
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - r10 = 0x0000000000000000 r11 = 0x0000000000000000
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - r12 = 0x00007ffcc19ac9c0 r13 = 0x0000000000000000
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - r14 = 0x0000000000000000 r15 = 0x00007ffcc19ac9c8
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - rip = 0x00007f1794e16b13
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - Found by: given as instruction pointer in context
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - 1 libxul.so!js::GlobalHelperThreadState::~GlobalHelperThreadState() [HelperThreads.h:226ed0ce4e27275652ae247d5090f82d49b58445 : 81 + 0x82]
[task 2020-08-28T22:56:02.774Z] 22:56:02 INFO - rbx = 0x00007f1785608400 rbp = 0x00007ffcc19ac980
[task 2020-08-28T22:56:02.775Z] 22:56:02 INFO - rsp = 0x00007ffcc19ac970 r12 = 0x00007ffcc19ac9c0
[task 2020-08-28T22:56:02.775Z] 22:56:02 INFO - r13 = 0x0000000000000000 r14 = 0x0000000000000000
[task 2020-08-28T22:56:02.775Z] 22:56:02 INFO - r15 = 0x00007ffcc19ac9c8 rip = 0x00007f1794e16342
[task 2020-08-28T22:56:02.775Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.775Z] 22:56:02 INFO - 2 libxul.so!js::DestroyHelperThreadsState() [HelperThreads.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 91 + 0x14]
[task 2020-08-28T22:56:02.775Z] 22:56:02 INFO - rbx = 0x00007f1785608400 rbp = 0x00007ffcc19ac9a0
[task 2020-08-28T22:56:02.775Z] 22:56:02 INFO - rsp = 0x00007ffcc19ac990 r12 = 0x00007ffcc19ac9c0
[task 2020-08-28T22:56:02.776Z] 22:56:02 INFO - r13 = 0x0000000000000000 r14 = 0x0000000000000000
[task 2020-08-28T22:56:02.776Z] 22:56:02 INFO - r15 = 0x00007ffcc19ac9c8 rip = 0x00007f1794e0332b
[task 2020-08-28T22:56:02.776Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.776Z] 22:56:02 INFO - 3 libxul.so!JS_ShutDown() [Initialization.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 237 + 0x5]
[task 2020-08-28T22:56:02.776Z] 22:56:02 INFO - rbx = 0x00007ffcc19ac9c8 rbp = 0x00007ffcc19ac9b0
[task 2020-08-28T22:56:02.777Z] 22:56:02 INFO - rsp = 0x00007ffcc19ac9b0 r12 = 0x00007ffcc19ac9c0
[task 2020-08-28T22:56:02.777Z] 22:56:02 INFO - r13 = 0x0000000000000000 r14 = 0x0000000000000000
[task 2020-08-28T22:56:02.778Z] 22:56:02 INFO - r15 = 0x00007ffcc19ac9c8 rip = 0x00007f1794eb6017
[task 2020-08-28T22:56:02.778Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.778Z] 22:56:02 INFO - 4 libxul.so!mozilla::ShutdownXPCOM(nsIServiceManager*) [XPCOMInit.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 744 + 0x5]
[task 2020-08-28T22:56:02.778Z] 22:56:02 INFO - rbx = 0x00007ffcc19ac9c8 rbp = 0x00007ffcc19aca10
[task 2020-08-28T22:56:02.779Z] 22:56:02 INFO - rsp = 0x00007ffcc19ac9c0 r12 = 0x00007ffcc19ac9c0
[task 2020-08-28T22:56:02.779Z] 22:56:02 INFO - r13 = 0x0000000000000000 r14 = 0x0000000000000000
[task 2020-08-28T22:56:02.779Z] 22:56:02 INFO - r15 = 0x00007ffcc19ac9c8 rip = 0x00007f1790b7ed9d
[task 2020-08-28T22:56:02.780Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.780Z] 22:56:02 INFO - 5 libxul.so!XRE_TermEmbedding() [nsEmbedFunctions.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 223 + 0x7]
[task 2020-08-28T22:56:02.780Z] 22:56:02 INFO - rbx = 0x00007f17a1035968 rbp = 0x00007ffcc19aca30
[task 2020-08-28T22:56:02.780Z] 22:56:02 INFO - rsp = 0x00007ffcc19aca20 r12 = 0x00007ffcc19aded8
[task 2020-08-28T22:56:02.781Z] 22:56:02 INFO - r13 = 0x0000000000000001 r14 = 0x000000000000000e
[task 2020-08-28T22:56:02.781Z] 22:56:02 INFO - r15 = 0x0000000080004005 rip = 0x00007f1794adb015
[task 2020-08-28T22:56:02.782Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.783Z] 22:56:02 INFO - 6 libxul.so!mozilla::ipc::ScopedXREEmbed::Stop() [ScopedXREEmbed.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 90 + 0x5]
[task 2020-08-28T22:56:02.783Z] 22:56:02 INFO - rbx = 0x00007f17a1035968 rbp = 0x00007ffcc19aca50
[task 2020-08-28T22:56:02.783Z] 22:56:02 INFO - rsp = 0x00007ffcc19aca40 r12 = 0x00007ffcc19aded8
[task 2020-08-28T22:56:02.784Z] 22:56:02 INFO - r13 = 0x0000000000000001 r14 = 0x000000000000000e
[task 2020-08-28T22:56:02.784Z] 22:56:02 INFO - r15 = 0x0000000080004005 rip = 0x00007f179118ad79
[task 2020-08-28T22:56:02.785Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.785Z] 22:56:02 INFO - 7 libxul.so!XRE_InitChildProcess(int, char**, XREChildData const*) [nsEmbedFunctions.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 748 + 0xe]
[task 2020-08-28T22:56:02.785Z] 22:56:02 INFO - rbx = 0x0000000000000001 rbp = 0x00007ffcc19acd30
[task 2020-08-28T22:56:02.786Z] 22:56:02 INFO - rsp = 0x00007ffcc19aca60 r12 = 0x00007ffcc19aded8
[task 2020-08-28T22:56:02.786Z] 22:56:02 INFO - r13 = 0x0000000000000001 r14 = 0x000000000000000e
[task 2020-08-28T22:56:02.786Z] 22:56:02 INFO - r15 = 0x0000000080004005 rip = 0x00007f1794adb5fc
[task 2020-08-28T22:56:02.787Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.787Z] 22:56:02 INFO - 8 firefox-bin!content_process_main(mozilla::Bootstrap*, int, char**) [plugin-container.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 56 + 0x11]
[task 2020-08-28T22:56:02.788Z] 22:56:02 INFO - rbx = 0x0000000000000010 rbp = 0x00007ffcc19acd70
[task 2020-08-28T22:56:02.788Z] 22:56:02 INFO - rsp = 0x00007ffcc19acd40 r12 = 0x00007ffcc19acd40
[task 2020-08-28T22:56:02.788Z] 22:56:02 INFO - r13 = 0x00007ffcc19aded0 r14 = 0x00007ffcc19aded8
[task 2020-08-28T22:56:02.789Z] 22:56:02 INFO - r15 = 0x00007f17a10026d0 rip = 0x0000561c20a1015e
[task 2020-08-28T22:56:02.789Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.789Z] 22:56:02 INFO - 9 firefox-bin!main [nsBrowserApp.cpp:226ed0ce4e27275652ae247d5090f82d49b58445 : 303 + 0x20]
[task 2020-08-28T22:56:02.790Z] 22:56:02 INFO - rbx = 0x0000000000000000 rbp = 0x00007ffcc19addf0
[task 2020-08-28T22:56:02.790Z] 22:56:02 INFO - rsp = 0x00007ffcc19acd80 r12 = 0x0000561c20a10000
[task 2020-08-28T22:56:02.790Z] 22:56:02 INFO - r13 = 0x00007ffcc19aded0 r14 = 0x0000561c20aac5e8
[task 2020-08-28T22:56:02.790Z] 22:56:02 INFO - r15 = 0x0000025c73017f24 rip = 0x0000561c20a104d1
[task 2020-08-28T22:56:02.790Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.791Z] 22:56:02 INFO - 10 libc.so.6 + 0x21b97
[task 2020-08-28T22:56:02.791Z] 22:56:02 INFO - rbx = 0x0000000000000000 rbp = 0x0000561c20aa90a0
[task 2020-08-28T22:56:02.791Z] 22:56:02 INFO - rsp = 0x00007ffcc19ade00 r12 = 0x0000561c20a10000
[task 2020-08-28T22:56:02.792Z] 22:56:02 INFO - r13 = 0x00007ffcc19aded0 r14 = 0x0000000000000000
[task 2020-08-28T22:56:02.792Z] 22:56:02 INFO - r15 = 0x0000000000000000 rip = 0x00007f17a14ccb97
[task 2020-08-28T22:56:02.792Z] 22:56:02 INFO - Found by: call frame info
[task 2020-08-28T22:56:02.793Z] 22:56:02 INFO - 11 firefox-bin!mozilla::UniquePtr<mozilla::Bootstrap, mozilla::Bootstrap::BootstrapDelete>::~UniquePtr() [UniquePtr.h:226ed0ce4e27275652ae247d5090f82d49b58445 : 253 + 0x17]
[task 2020-08-28T22:56:02.793Z] 22:56:02 INFO - rsp = 0x00007ffcc19ade20 rip = 0x0000561c20a101a1
[task 2020-08-28T22:56:02.793Z] 22:56:02 INFO - Found by: stack scanning

This is likely not caused within MFBT, but by the uses with js::ParseTask.