Crash report: https://crash-stats.mozilla.org/report/index/3793e9c6-26cc-4087-89bd-ab45c0230817

MOZ_CRASH Reason: MOZ_RELEASE_ASSERT(isSome())

Top 10 frames of crashing thread:

0  libxul.so  js::gc::GCRuntime::collect  js/src/gc/GC.cpp
1  libxul.so  GarbageCollectImpl  dom/base/nsJSEnvironment.cpp
2  libxul.so  nsJSContext::RunIncrementalGCSlice  dom/base/nsJSEnvironment.cpp:1091
2  libxul.so  mozilla::CCGCScheduler::GCRunnerFiredDoGC  dom/base/CCGCScheduler.cpp:427
2  libxul.so  mozilla::CCGCScheduler::GCRunnerFired  dom/base/CCGCScheduler.cpp:386
2  libxul.so  mozilla::CCGCScheduler::EnsureGCRunner const  dom/base/CCGCScheduler.cpp:617
2  libxul.so  std::_Function_handler<bool   /builds/worker/fetches/sysroot-x86_64-linux-gnu/usr/include/c++/8/bits/std_function.h:282
3  libxul.so  std::function<bool  const  /builds/worker/fetches/sysroot-x86_64-linux-gnu/usr/include/c++/8/bits/std_function.h:687
3  libxul.so  mozilla::IdleTaskRunner::Run  xpcom/threads/IdleTaskRunner.cpp:125
4  libxul.so  mozilla::TimedOut  xpcom/threads/IdleTaskRunner.cpp:143

Low volume crash, but it is a release assert, so maybe this is fixable? Though I don't know if any of these reports have actual line numbers for where the check is failing.

My guess is that this is GCRuntime::maybeGcOptions asserting as there were some problems with this before, but it's hard to tell from this information.

lately, this bug seems to be a tiny bit more frequent on nightly, which might blow up on beta and release.

Jon, would it be possible to instrument the assertion to report more information in order to figure out what might be going on?