For example: https://treeherder.mozilla.org/ui/logviewer.html#?repo=fx-team&job_id=1474029 Or in brief: 19:45:35 INFO - Assertion failure: !phaseStartTimes[phase], at /builds/slave/fx-team-l64-d-0000000000000000/build/src/js/src/gc/Statistics.cpp:886 19:45:36 INFO -  ###!!! ABORT: Aborting on channel error.: file /builds/slave/fx-team-l64-d-0000000000000000/build/src/ipc/glue/MessageChannel.cpp, line 1519 19:45:36 INFO - #01: mozilla::ipc::ProcessLink::OnChannelError() [ipc/glue/MessageLink.cpp:405] 19:45:36 INFO - #02: IPC::Channel::ChannelImpl::OnFileCanReadWithoutBlocking(int) [ipc/chromium/src/chrome/common/ipc_channel_posix.cc:854] . . . So the assertion is in js/src/gc/Statistics.cpp, but the stack trace in the log only shows mozilla::ipc::ProcessLink::OnChannelError(). This would be a pretty easy error to diagnose with a proper stack. But it's a rare intermittent, and tough to figure out without one. I don't know if this bug belongs in IPC or breakpad or what.
...and I'm blind. The proper stack *is* in the log. If anything, this is a treeherder bug for only showing the useless stack in the summary pane of the log viewer.
Could you give and expected vs actual? I'm not sure precisely what you are asking for here. It doesn't seem like this is a treeherder bug, but a log output bug, unless I'm misunderstanding (and unless we start making Treeherder mangle the log output, which is not something we've ever done before).
Doh! Actually, I missed it. The log viewer *does* pull out a PROCESS-CRASH line, which is all I needed. It's just cluttered up with a bunch of useless information like the IPC stack, but that's an IPC log output problem.