494721 - Crash in XPCJSRuntime::WatchdogMain

Status: RESOLVED DUPLICATE of bug 494973

(Core :: XPConnect, defect)

Description

[Hiroyuki Ikezoe (:hiro)]

This crash is very weird. It is occurred in unloaded module, so I can not get stack traces with valid symbols. As far as I investigate the first address of the following traces, it seems to be http://mxr.mozilla.org/mozilla-central/source/js/src/xpconnect/src/xpcjsruntime.cpp#807


Stack trace:

    0x7a092fd0
    0x7820c108
    0x78205308
    0x78209b54
    0x03f6732c

Unfortunately, there is no symbols since these addresses (at least top four
addresses) seem to be functions in xul.dll. But xul.dll is already unloaded.

The last log is:

Unload module: xpcom.dll
Unload module: softokn3.dll
nsStringStats
 => mAllocCount:          13354
 => mReallocCount:         2151
 => mFreeCount:           12264  --  LEAKED 1090 !!!
 => mShareCount:          14363
 => mAdoptCount:           1150
 => mAdoptFreeCount:       1148  --  LEAKED 2 !!!
Unload module: xul.dll
Unload module: sqlite3.dll
Unload module: js3250.dll
Unload module: smime3.dll
Unload module: ssl3.dll
Prefetch Abort: Thread=9fc01000 Proc=80096ec0 'fennec.exe'
Unload module: nss3.dll
AKY=00001001 PC=7a092fd0(???+0x7a092fd0) RA=7820c108(nspr4.dll+0x0003c108)
BVA=7a092fd0 FSR=00000407
Unload module: nssutil3.dll
Unload module: plc4.dll
Unhandled exception at 0x7a092fd0 in fennec.exe: 0xC0000005: Access violation
reading location 0x7a092fd0.

Comment 1

[Hiroyuki Ikezoe (:hiro)]

This crash happens when I terminate Fennec by task manager.

I guess the reason of the crash is that the destructor of XPCJSRuntime is not called while exiting Fennec.

The destructor of XPCJRuntime is not called too on Linux, but there is no crash. Maybe watchdog thread is cleaned implicitly.

Comment 2

[timeless]

wait, terminate by task manager? does that mean it goes through some strange event loop triggered thing?

again, the problem is that the signal used to tell the thread to die isn't being sent.

please use a debugger to get the stack trace for FreeLibrary.

Comment 3

[Hiroyuki Ikezoe (:hiro)]

(In reply to comment #2)
> wait, terminate by task manager? 

Yes. Fennec on WinCE does not have the function for application exit. It can not be terminated without task manager.

> again, the problem is that the signal used to tell the thread to die isn't
> being sent.
> 
> please use a debugger to get the stack trace for FreeLibrary.

IIRC, the library which was unloaded while crashing is not the same all time.

Comment 4

[Hiroyuki Ikezoe (:hiro)]

Unload module: smime3.dll
Prefetch Abort: Thread=9dc79b38 Proc=80096ec0 'fennec.exe'
Unload module: ssl3.dll
AKY=00001001 PC=7a092fe4(???+0x7a092fe4) RA=7820c108(nspr4.dll+0x0003c108) BVA=7a092fe4 FSR=00000407
Unload module: nss3.dll
Unload module: nssutil3.dll
Unhandled exception at 0x7a092fe4 in fennec.exe: 0xC0000005: Access violation reading location 0x7a092fe4.

This time the crash was happened after nssutil3.dll was unloaded. According to the trace in comment #0, the next module which should be unloaded is plc4.dll.

Comment 5

[Hiroyuki Ikezoe (:hiro)]

(In reply to comment #1)

> The destructor of XPCJRuntime is not called too on Linux, but there is no
> crash. Maybe watchdog thread is cleaned implicitly.

On Linux, I terminate Fennec by "close button" at the top left of window so Fennec should terminate harmlessly.

Comment 6

[timeless]

i don't care. heck, get me stack traces for *each* FreeLibrary call.

Comment 7

[Hiroyuki Ikezoe (:hiro)]

Unfortunately, I can not get stack traces in xul.dll since FreeLibrary in XPCOMGlueUnload seems to be not called when application is terminated by task manager.

I use Visual Studio 2008 and set a break point at the call of FreeLibrary, but can not be stopped at there.  And debug print with wprintf does not output anything.

Do you have any idea to get stack traces correctly?

Comment 8

[Hiroyuki Ikezoe (:hiro)]

Mark, thank you very much! 

I confirmed the crash has gone after this changeset.

http://hg.mozilla.org/mobile-browser/rev/627870ff78ab