Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b4pre) Gecko/20100805 Minefield/4.0b4pre Open planet.mozilla.org and another tab of your choosing drag the tab in to its own window and back into the first window till the browser hangs I have a copy of planet for the day that I saw this and the local copy displays the same issue. Too big to be attached to the bug http://dl.dropbox.com/u/686313/planet.zip I have two dump files of this hang if you have trouble reproducing this. Both are quite large ~200mb and 800mb respectively. Ping on irc or comment and I'll arrange for a way to get them to you. STACK_TEXT: 0040ad48 76830816 000000c0 00000000 00000000 ntdll_775e0000!ZwWaitForSingleObject+0x15 0040adb4 76501184 000000c0 ffffffff 00000000 KERNELBASE!WaitForSingleObjectEx+0x98 0040adcc 76501138 000000c0 ffffffff 00000000 kernel32!WaitForSingleObjectExImplementation+0x75 0040ade0 73eef3d9 000000c0 ffffffff 02e33350 kernel32!WaitForSingleObject+0x12 0040ae04 73eeaf48 02e334e4 02e3336c ffffffff nspr4!_PR_MD_WAIT_CV+0xc9 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\nsprpub\pr\src\md\windows\w95cv.c @ 282] 0040ae24 73eeb06b ffffffff 1191bc50 00000001 nspr4!_PR_WaitCondVar+0x58 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\nsprpub\pr\src\threads\combined\prucv.c @ 205] 0040ae38 73b90a14 02e33470 ffffffff 0090f000 nspr4!PR_WaitCondVar+0x3b [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\nsprpub\pr\src\threads\combined\prucv.c @ 547] 0040ae5c 73af95c1 1191bc50 00000000 189d22a0 mozjs!BeginGCSession+0x97524 0040ae78 73afec3e 189ecf60 189d22a0 1191bc50 mozjs!js::SetProtoCheckingForCycles+0x31 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsgc.cpp @ 3572] 0040ae94 73afeb76 189ecf01 189d22a0 00000001 mozjs!js::SetProto+0x9e [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsobj.cpp @ 3644] 0040aeb8 73b200c8 1191bc50 189ecf60 00000001 mozjs!obj_setProto+0x66 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsobj.cpp @ 171] 0040aecc 73b113b7 1191bc50 73afeb10 189ecf60 mozjs!js::callJSPropertyOpSetter+0x18 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jscntxtinlines.h @ 385] 0040af00 73b2b0ec 03e978a1 0040b010 00000036 mozjs!JSScopeProperty::set+0xc7 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsscopeinlines.h @ 342] 0040af64 73b396f3 1191bc50 189ecf60 03f00860 mozjs!js_SetPropertyHelper+0x7fc [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsobj.cpp @ 5132] 0040b664 73b36886 1191bc50 08d230d8 0040b6dc mozjs!js::Interpret+0x2bb3 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 4396] 0040b6a8 73b40611 08d230d8 078e7e50 00000000 mozjs!js::InvokeCommon<int (__cdecl*)(JSContext *,JSObject *,unsigned int,js::Value *,js::Value *)>+0x246 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 589] 0040b6dc 73b2b658 1191bc50 0040b718 00000000 mozjs!js::Invoke+0xa1 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 691] 0040b72c 73b36fad 1191bc50 00000002 03a00550 mozjs!js_fun_apply+0x218 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsfun.cpp @ 2167] 0040be2c 73b36886 1191bc50 03f746c0 0040bea4 mozjs!js::Interpret+0x46d [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 4746] 0040be70 73b40611 03f746c0 045d0ac0 00000000 mozjs!js::InvokeCommon<int (__cdecl*)(JSContext *,JSObject *,unsigned int,js::Value *,js::Value *)>+0x246 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 589] 0040bea4 6c5bbf9e 1191bc50 0040bf44 00000000 mozjs!js::Invoke+0xa1 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 691] 0040c0e0 6c59a7d8 061113a0 0816ad00 00000003 xul!nsXPCWrappedJSClass::CallMethod+0x89e [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\xpconnect\src\xpcwrappedjsclass.cpp @ 1692] 0040c0f8 6c7a70cf 0816ad00 00000003 02eb4ee0 xul!nsXPCWrappedJS::CallMethod+0x38 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\xpconnect\src\xpcwrappedjs.cpp @ 571] 0040c1ac 6c7a7139 0793ad10 00000003 0040c1d4 xul!PrepareAndDispatch+0xe8 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\xpcom\reflect\xptcall\src\md\win32\xptcstubs.cpp @ 114] 0040c1c8 6c67c8b7 0793ad10 26307220 0ea353c8 xul!SharedStub+0x16 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\xpcom\reflect\xptcall\src\md\win32\xptcstubs.cpp @ 142] 0040c1e0 6c5cbafb 00000000 0040c40c 0040c354 xul!nsEventListenerManager::HandleEventSubType+0x38 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventlistenermanager.cpp @ 1106] 0040c2b4 6c5a3b93 26307220 0ea353c8 0040c3ac xul!XPCWrappedNative::GetNewOrUsed+0x74b [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\xpconnect\src\xpcwrappednative.cpp @ 600] 0040c35c 6c5c944a 25ca7da0 00000006 00000000 xul!nsEventListenerManager::HandleEventInternal+0x1b3 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventlistenermanager.cpp @ 1202] 0040c3fc 6c58c257 27ae91c0 093a9000 26307250 xul!nsEventDispatcher::Dispatch+0x43a [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventdispatcher.cpp @ 632] 0040c438 6c641a52 27ae91c0 00000000 26307220 xul!nsEventDispatcher::DispatchDOMEvent+0xa7 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventdispatcher.cpp @ 691] 0040c45c 6c6527f8 27ae91c0 26307220 0040c4a4 xul!nsEventListenerManager::DispatchEvent+0x92 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventlistenermanager.cpp @ 1320] 0040c474 6c6551b9 1c14ed38 26307220 0040c4a4 xul!nsDOMEventRTTearoff::DispatchEvent+0x3a [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\base\src\nsgenericelement.cpp @ 1973] 0040c4ac 73b36fad 1191bc50 00000001 03a004b0 xul!nsIDOMEventTarget_DispatchEvent+0x99 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\obj-firefox\js\src\xpconnect\src\dom_quickstubs.cpp @ 13781] 0040cba4 73b36886 1191bc50 0cc41048 0040cc18 mozjs!js::Interpret+0x46d [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 4746] 0040cbe8 73b40611 0cc41048 0aec7240 00000000 mozjs!js::InvokeCommon<int (__cdecl*)(JSContext *,JSObject *,unsigned int,js::Value *,js::Value *)>+0x246 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 589] 0040cc18 73b30738 1191bc50 0040cc48 00000000 mozjs!js::Invoke+0xa1 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 691] 0040cc5c 73b16e23 1191bc50 0040cc88 0040cca4 mozjs!js::InternalInvoke+0x108 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsinterp.cpp @ 754] 0040cc94 6c646581 1191bc50 357e7960 14d9e6f0 mozjs!JS_CallFunctionValue+0x43 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\js\src\jsapi.cpp @ 4834] 0040cd4c 6c55f25f 1ca7df80 214cd480 14d9e6f0 xul!nsJSContext::CallEventHandler+0x1e1 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\dom\base\nsjsenvironment.cpp @ 2249] 0040ce48 6c67c8b7 1da25fc0 16c554c0 1ca7df80 xul!nsJSEventListener::HandleEvent+0x11f [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\dom\src\events\nsjseventlistener.cpp @ 228] 0040cf34 6c5a3b93 16c554c0 1ca7df80 0040d02c xul!nsEventListenerManager::HandleEventSubType+0x38 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventlistenermanager.cpp @ 1106] 0040cf90 6c5b1f73 24ca09e0 08956c00 0040d180 xul!nsEventListenerManager::HandleEventInternal+0x1b3 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventlistenermanager.cpp @ 1202] 0040cfdc 6c5c944a 1b507350 00000006 0040d0d0 xul!nsEventTargetChainItem::HandleEventTargetChain+0x483 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventdispatcher.cpp @ 364] 0040d07c 6c702d96 1870b4c0 08956c00 0040d180 xul!nsEventDispatcher::Dispatch+0x43a [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventdispatcher.cpp @ 632] 0040d0e0 6cce7601 08246e80 0040d180 00000000 xul!PresShell::HandleEventInternal+0x280 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\layout\base\nspresshell.cpp @ 6693] 0040d0f8 6cab5ce1 0040d180 1b7d9140 1870b4c0 xul!PresShell::HandleEventWithTarget+0x22 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\layout\base\nspresshell.cpp @ 6550] 0040d1ec 6c9462f5 08246e80 1870b4c0 0040d488 xul!nsEventStateManager::CheckForAndDispatchClick+0x10b [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\content\events\src\nseventstatemanager.cpp @ 3940] 0040d390 6c702d3a 133e45e8 08956c00 0040d598 xul!nsEventStateManager::PostHandleEvent+0x24390f 0040d3f4 6c71d7be 08246e80 0040d598 14b3f400 xul!PresShell::HandleEventInternal+0x224 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\layout\base\nspresshell.cpp @ 6716] 0040d41c 6c71d627 14b3f400 0040d598 0040d488 xul!PresShell::HandlePositionedEvent+0x9c [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\layout\base\nspresshell.cpp @ 6535] 0040d468 6c71d710 08246ef8 14b3f400 0040d598 xul!PresShell::HandleEvent+0x21d [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\layout\base\nspresshell.cpp @ 6412] 0040d48c 6c599b4f 0040d598 0040d598 14b3f400 xul!nsViewManager::HandleEvent+0x34 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\view\src\nsviewmanager.cpp @ 1085] 0040d4f8 6c577e6c 10a858d0 0040d598 14b3f400 xul!nsViewManager::DispatchEvent+0x4bf [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\view\src\nsviewmanager.cpp @ 1060] 0040d520 6c560a7b 0d4c9360 00000000 0000012d xul!HandleEvent+0x8c [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\view\src\nsview.cpp @ 161] 0040d534 6c560a35 157d0300 0040d598 0040d550 xul!nsWindow::DispatchEvent+0x2b [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\widget\src\windows\nswindow.cpp @ 3642] 0040d548 6c51bbce 00000000 62058d6b 00000208 xul!nsWindow::DispatchWindowEvent+0x13 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\widget\src\windows\nswindow.cpp @ 3666] 0040d60c 6c9560a8 0000012d 00000000 0128014b xul!nsWindow::DispatchMouseEvent+0x2c2 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\widget\src\windows\nswindow.cpp @ 4076] 0040d73c 6c57ca61 00000208 0040d788 0040d78c xul!nsWindow::ProcessMessage+0x3e76b8 0040d778 76366238 00000001 00000208 00000000 xul!nsWindow::WindowProc+0xf1 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\widget\src\windows\nswindow.cpp @ 4400] 0040d7a4 763668ea 6c57c970 000e087a 00000208 user32!InternalCallWinProc+0x23 0040d81c 76367d31 00000000 6c57c970 000e087a user32!UserCallWinProcCheckWow+0x109 0040d87c 76367dfa 6c57c970 00000000 00000000 user32!DispatchMessageWorker+0x3bc 0040d88c 6c5e4679 0040d8c8 0091a4c0 00000000 user32!DispatchMessageW+0xf 0040d918 6c5d4d68 03e4b944 0091a4c0 00000001 xul!nsBaseAppShell::OnProcessNextEvent+0x3f9 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\widget\src\xpwidgets\nsbaseappshell.cpp @ 312] 0040d94c 6c580d98 00000000 00000001 0040d97c xul!nsThread::ProcessNextEvent+0x178 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\xpcom\threads\nsthread.cpp @ 519] 0040d98c 6c78abd1 0093f3c0 0093f3c0 6c78abba xul!mozilla::ipc::MessagePump::Run+0x1a8 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\ipc\glue\messagepump.cpp @ 143] 0040d998 6c78abba 620581e3 0091a4c0 03e4b940 xul!MessageLoop::RunInternal+0x11 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\ipc\chromium\src\base\message_loop.cc @ 219] 0040d9d0 6c78ab62 6205823b 0091a4c0 03e4b940 xul!MessageLoop::RunHandler+0x1d [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\ipc\chromium\src\base\message_loop.cc @ 203] 0040da08 6c770af8 00000000 03e4b940 6c798f94 xul!MessageLoop::Run+0x1f [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\ipc\chromium\src\base\message_loop.cc @ 177] 0040da14 6c798f94 03e4b940 03e6e1f0 00f80000 xul!nsBaseAppShell::Run+0x34 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\widget\src\xpwidgets\nsbaseappshell.cpp @ 181] 0040f968 6c798f3e 03e4b940 0040f9e0 6c6d00ef xul!nsAppShell::Run+0x42 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\widget\src\windows\nsappshell.cpp @ 249] 0040f974 6c6d00ef 03e6e1f0 0092f0a0 00000001 xul!nsAppStartup::Run+0x1e [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\toolkit\components\startup\src\nsappstartup.cpp @ 192] 0040fbe4 00f8134c 00000001 0092f0a0 00917380 xul!XRE_main+0xc9f [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\toolkit\xre\nsapprunner.cpp @ 3649] 0040fc34 00f816f2 00000001 00919220 009121b0 firefox!wmain+0x34c [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\toolkit\xre\nswindows FOLLOWUP_IP: nspr4!_PR_MD_WAIT_CV+c9 [e:\builds\moz2_slave\mozilla-central-win32-nightly\build\nsprpub\pr\src\md\windows\w95cv.c @ 282] 73eef3d9 8b4d0c mov ecx,dword ptr [ebp+0Ch] SYMBOL_STACK_INDEX: 4 SYMBOL_NAME: nspr4!_PR_MD_WAIT_CV+c9 FOLLOWUP_NAME: MachineOwner MODULE_NAME: nspr4 IMAGE_NAME: nspr4.dll DEBUG_FLR_IMAGE_TIMESTAMP: 4c5803ee STACK_COMMAND: ~0s ; kb BUCKET_ID: X64_HANG_nspr4!_PR_MD_WAIT_CV+c9 FAILURE_BUCKET_ID: APPLICATION_HANG_BusyHang_cfffffff_nspr4.dll!_PR_MD_WAIT_CV

Bug 584057?