1254652 - NS_ENSURE_TRUE(context) failed during nsThread::Shutdown

Status: NEW

(Core :: XPCOM, defect)

Description

[Nathan Froyd [:froydnj]]

This warning shows up during debug runs:

11:36:04     INFO -  [1881] WARNING: NS_ENSURE_TRUE(context) failed: file /builds/slave/m-in-lx-d-00000000000000000000/build/src/xpcom/threads/nsThread.cpp, line 805

I noticed it today in my local build and added NS_ASSERTION:

[11220] ###!!! ASSERTION: ouch!: 'context', file /home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp, line 805
#01: nsRunnableMethodImpl<nsresult (nsIThread::*)(), true>::Run() (/opt/build/froydnj/build-debug/dist/include/nsThreadUtils.h:873)
#02: nsThread::ProcessNextEvent(bool, bool*) (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:1000)
#03: NS_ProcessNextEvent(nsIThread*, bool) (/home/froydnj/src/gecko-dev.git/xpcom/glue/nsThreadUtils.cpp:297)
#04: nsThread::Shutdown() (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:810)
#05: nsRunnableMethodImpl<nsresult (nsIThread::*)(), true>::Run() (/opt/build/froydnj/build-debug/dist/include/nsThreadUtils.h:873)
#06: nsThread::ProcessNextEvent(bool, bool*) (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:1000)
#07: NS_ProcessNextEvent(nsIThread*, bool) (/home/froydnj/src/gecko-dev.git/xpcom/glue/nsThreadUtils.cpp:297)
#08: nsThread::Shutdown() (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:810)
#09: nsRunnableMethodImpl<nsresult (nsIThread::*)(), true>::Run() (/opt/build/froydnj/build-debug/dist/include/nsThreadUtils.h:873)
#10: nsThread::ProcessNextEvent(bool, bool*) (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:1000)
#11: NS_ProcessNextEvent(nsIThread*, bool) (/home/froydnj/src/gecko-dev.git/xpcom/glue/nsThreadUtils.cpp:297)
#12: nsThread::Shutdown() (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:810)
#13: mozilla::dom::workers::RuntimeService::NoteIdleThread(mozilla::dom::workers::WorkerThread*) (/home/froydnj/src/gecko-dev.git/dom/workers/RuntimeService.cpp:2373)
#14: ~RefPtr (/opt/build/froydnj/build-debug/dist/include/mozilla/RefPtr.h:76)
#15: nsThread::ProcessNextEvent(bool, bool*) (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:1000)
#16: NS_ProcessNextEvent(nsIThread*, bool) (/home/froydnj/src/gecko-dev.git/xpcom/glue/nsThreadUtils.cpp:297)
#17: nsThread::Shutdown() (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:810)
#18: mozilla::dom::workers::RuntimeService::NoteIdleThread(mozilla::dom::workers::WorkerThread*) (/home/froydnj/src/gecko-dev.git/dom/workers/RuntimeService.cpp:2373)
#19: ~RefPtr (/opt/build/froydnj/build-debug/dist/include/mozilla/RefPtr.h:76)
#20: nsThread::ProcessNextEvent(bool, bool*) (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:1000)
#21: NS_ProcessNextEvent(nsIThread*, bool) (/home/froydnj/src/gecko-dev.git/xpcom/glue/nsThreadUtils.cpp:297)
#22: nsThread::Shutdown() (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:810)
#23: mozilla::dom::workers::RuntimeService::NoteIdleThread(mozilla::dom::workers::WorkerThread*) (/home/froydnj/src/gecko-dev.git/dom/workers/RuntimeService.cpp:2373)
#24: ~RefPtr (/opt/build/froydnj/build-debug/dist/include/mozilla/RefPtr.h:76)
#25: nsThread::ProcessNextEvent(bool, bool*) (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:1000)
#26: NS_ProcessNextEvent(nsIThread*, bool) (/home/froydnj/src/gecko-dev.git/xpcom/glue/nsThreadUtils.cpp:297)
#27: nsThread::Shutdown() (/home/froydnj/src/gecko-dev.git/xpcom/threads/nsThread.cpp:810)
#28: nsTArray_base<nsTArrayInfallibleAllocator, nsTArray_CopyWithMemutils>::Length() const (/opt/build/froydnj/build-debug/dist/include/nsTArray.h:361)
#29: nsTArray_base<nsTArrayInfallibleAllocator, nsTArray_CopyWithMemutils>::Length() const (/opt/build/froydnj/build-debug/dist/include/nsTArray.h:361)
#30: nsTHashtable<nsObserverList>::GetEntry(char const*) const (/opt/build/froydnj/build-debug/dist/include/nsTHashtable.h:134)
#31: mozilla::ShutdownXPCOM(nsIServiceManager*) (/home/froydnj/src/gecko-dev.git/xpcom/build/XPCOMInit.cpp:868)
#32: ~nsCOMPtr (/opt/build/froydnj/build-debug/dist/include/nsCOMPtr.h:403)
#33: operator delete (/opt/build/froydnj/build-debug/dist/include/mozilla/mozalloc.h:210)
#34: XRE_main (/home/froydnj/src/gecko-dev.git/toolkit/xre/nsAppRunner.cpp:4516)
#35: do_main (/home/froydnj/src/gecko-dev.git/browser/app/nsBrowserApp.cpp:212)
#36: main (/home/froydnj/src/gecko-dev.git/browser/app/nsBrowserApp.cpp:360)
#37: __libc_start_main (/build/glibc-I9DIZl/glibc-2.19/csu/libc-start.c:321)
#38: _start (/opt/build/froydnj/build-debug/dist/bin/firefox)
#39: ??? (???:???)

We are draining event queues via nested event loops?  Seems not so great.

ni? to khuey for thoughts and also maybe an explanation of what's going on with the worker stuff in there?

Comment 1

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

This warning appears if

a) We call shutdown on a thread from that thread.
b) We call shutdown twice on the same thread.

In both cases the shutdown call that warns becomes a no-op.  I guess before we didn't warn in case b, we could restore that behavior if you care. http://hg.mozilla.org/mozilla-central/rev/6bb087e3ec08#l4.136