Bug 48896 – Keep a reference to the scrollbar in accessibility scrollbar.

• Component: Accessibility
• Status: RESOLVED FIXED

[Chris Guillory]

Chromium canaries are observing crashes on the following tests:
Regressions: Unexpected DumpRenderTree crashes : (3)
  fast/dom/cssTarget-crash.html = CRASH
  fast/events/node-event-anchor-lock.html = CRASH
  fast/loader/repeat-same-document-navigation.html = CRASH

Caused by change http://trac.webkit.org/changeset/71198.

[Chris Guillory]

Created attachment 72786 [details]
Null check obj

[Roland Steiner]

Comment on attachment 72786 [details]
Null check obj

Clearing flags on attachment: 72786

Committed r71208: <http://trac.webkit.org/changeset/71208>

[Roland Steiner]

All reviewed patches have been landed.  Closing bug.

[Dumitru Daniliuc]

fast/events/remove-event-listener.html started crashing on chromium win/linux/mac between r71198 and r71213 with the following stack trace:

[23234:23234:1304399625227:ERROR:process_util_posix.cc(105)] Received signal 11
	base::debug::StackTrace::StackTrace() [0x8111a79]
	base::(anonymous namespace)::StackDumpSignalHandler() [0x80fe039]
	0x4001c420
	WebCore::AXObjectCache::notificationPostTimerFired() [0x86de224]
	WebCore::Timer<>::fired() [0x86dc4f5]
	WebCore::ThreadTimers::sharedTimerFiredInternal() [0x86ca0b4]
	WebCore::ThreadTimers::sharedTimerFired() [0x86ca161]
	MessageLoop::RunTask() [0x80f072b]
	MessageLoop::DeferOrRunPendingTask() [0x80f097c]
	MessageLoop::DoWork() [0x80f0b8a]
	base::MessagePumpForUI::RunWithDispatcher() [0x810b7fc]
	base::MessagePumpForUI::Run() [0x810b782]
	MessageLoop::RunInternal() [0x80f10e5]
	MessageLoop::Run() [0x80f11d8]
	TestShell::WaitTestFinished() [0x8061416]
	TestShell::RunFileTest() [0x8061734]
	main [0x805a9d4]
	0x40a97450
	0x8058841

looks related to your patch. can you please take a look?

there's an entry for this test in chromium/src/webkit/tools/layout_tests/test_expectations.txt. once this test is no longer crashing, please remove that entry too.

[Chris Guillory]

Looking at the latest builds:
http://build.chromium.org/p/chromium/builders/Webkit%20Win/builds/1143/steps/webkit_tests/logs/stdio
http://build.chromium.org/p/chromium/builders/Webkit%20Mac10.5/builds/573/steps/webkit_tests/logs/stdio
http://build.chromium.org/p/chromium/builders/Webkit%20Linux/builds/1242/steps/webkit_tests/logs/stdio

fast/events/remove-event-listener.html is passing on windows and linux but failing on mac with error that looks unrelated.

2010-11-04 16:09:41,819 dump_render_tree_thread.py:107  DEBUG Stacktrace for /b/build/slave/Webkit_Mac10_5/build/src/third_party/WebKit/LayoutTests/fast/events/remove-event-listener.html:
[80036:267:1379177625481995:ERROR:/b/build/slave/webkit-mac-rel/build/src/base/process_util_posix.cc(105)] Received signal 10
	0   TestShell                           0x000a1bb1 _mh_execute_header + 658353
	1   TestShell                           0x000c2439 _mh_execute_header + 791609
	2   libSystem.B.dylib                   0x911c32bb _sigtramp + 43
	3   ???                                 0xffffffff 0x0 + 4294967295
	4   TestShell                           0x00d588c2 _mh_execute_header + 13990082
	5   TestShell                           0x00d5a46b _mh_execute_header + 13997163
	6   TestShell                           0x00d48ffe _mh_execute_header + 13926398
	7   TestShell                           0x00d490a2 _mh_execute_header + 13926562
	8   TestShell                           0x000b0c5c _mh_execute_header + 719964
	9   TestShell                           0x000b0e8e _mh_execute_header + 720526
	10  TestShell                           0x000b0ff7 _mh_execute_header + 720887
	11  TestShell                           0x000dbe94 _mh_execute_header + 896660
	12  CoreFoundation                      0x91ce83c5 CFRunLoopRunSpecific + 3141
	13  CoreFoundation                      0x91ce8aa8 CFRunLoopRunInMode + 88
	14  HIToolbox                           0x97a6a2ac BlockUntilNextEventMatchingListInMode + 989
	15  HIToolbox                           0x97a6a0c5 BlockUntilNextEventMatchingListInMode + 502
	16  HIToolbox                           0x97a69f39 BlockUntilNextEventMatchingListInMode + 106
	17  AppKit                              0x96b916d5 _DPSNextEvent + 657
	18  AppKit                              0x96b90f88 _NSUpdateMenuRefWithChangedMenuItem + 2250
	19  AppKit                              0x96b89f9f _NSSetViewMultiClipDrawingHelper + 4866
	20  TestShell                           0x000dbb5d _mh_execute_header + 895837
	21  TestShell                           0x000db02a _mh_execute_header + 892970
	22  TestShell                           0x000b186f _mh_execute_header + 723055
	23  TestShell                           0x000b19f4 _mh_execute_header + 723444
	24  TestShell                           0x00030c0d _mh_execute_header + 195597
	25  TestShell                           0x00032086 _mh_execute_header + 200838
	26  TestShell                           0x0000bc9e _mh_execute_header + 44190
	27  TestShell                           0x00009f2a _mh_execute_header + 36650

[Dumitru Daniliuc]

Roland said he couldn't reproduce the failure either, but most probably you need to run multiple tests for that failure to show up. I'm not sure how to reproduce it, but the stack trace reported on the Linux bot when this test started crashing seems to point to your patch.

[Chris Guillory]

Is it still failing somewhere that accessibility code stack trace? I see this test passing on Linux.

[Dumitru Daniliuc]

http://test-results.appspot.com/dashboards/flakiness_dashboard.html#showExpectations=true&tests=fast%2Fevents%2Fremove-event-listener.html

the test seems to no longer crash on linux. however, it still crashes on mac, in process_util_posix.cc(105), the same location where the test crashed on linux once (the rest of the stack trace from the mac bot looks unhelpful). and there might be a way to resolve those symbols in the windows stack trace.

[Chris Guillory]

Able to repro on windows debug with:
>run_webkit_tests.bat --debug fast/events

Backtrace:
	WebCore::AXObjectCache::postPlatformNotification [0x10079972+130] (c:\chromium2\src\third_party\webkit\webcore\accessibility\chromium\axobjectcachechromium.cpp:55)
	WebCore::AXObjectCache::notificationPostTimerFired [0x0FD962A7+279] (c:\chromium2\src\third_party\webkit\webcore\accessibility\axobjectcache.cpp:416)
	WebCore::Timer<WebCore::AXObjectCache>::fired [0x0FD96F73+35] (c:\chromium2\src\third_party\webkit\webcore\platform\timer.h:98)
	WebCore::ThreadTimers::sharedTimerFiredInternal [0x104C4CD9+217] (c:\chromium2\src\third_party\webkit\webcore\platform\threadtimers.cpp:112)
	WebCore::ThreadTimers::sharedTimerFired [0x104C4BF6+22] (c:\chromium2\src\third_party\webkit\webcore\platform\threadtimers.cpp:91)
	webkit_glue::WebKitClientImpl::DoTimeout [0x01143DAB+43] (c:\chromium2\src\webkit\glue\webkitclient_impl.h:68)
	DispatchToMethod<webkit_glue::WebKitClientImpl,void (__thiscall webkit_glue::WebKitClientImpl::*)(void)> [0x01145B3C+12] (c:\chromium2\src\base\tuple.h:537)
	base::BaseTimer<webkit_glue::WebKitClientImpl,0>::TimerTask::Run [0x01145094+84] (c:\chromium2\src\base\timer.h:160)
	MessageLoop::RunTask [0x016F77E9+361] (c:\chromium2\src\base\message_loop.cc:417)
	MessageLoop::DeferOrRunPendingTask [0x016F7935+53] (c:\chromium2\src\base\message_loop.cc:429)
	MessageLoop::DoWork [0x016F7EFC+236] (c:\chromium2\src\base\message_loop.cc:533)
	base::MessagePumpForUI::DoRunLoop [0x0178E364+84] (c:\chromium2\src\base\message_pump_win.cc:200)
	base::MessagePumpWin::RunWithDispatcher [0x0178D9E2+130] (c:\chromium2\src\base\message_pump_win.cc:49)
	base::MessagePumpWin::Run [0x0178DD8C+28] (c:\chromium2\src\base\message_pump_win.h:80)
	MessageLoop::RunInternal [0x016F6C2D+349] (c:\chromium2\src\base\message_loop.cc:265)
	MessageLoop::RunHandler [0x016F699E+46] (c:\chromium2\src\base\message_loop.cc:238)
	MessageLoop::Run [0x016F6840+96] (c:\chromium2\src\base\message_loop.cc:216)
	TestShell::WaitTestFinished [0x0187E653+675] (c:\chromium2\src\webkit\tools\test_shell\test_shell_win.cc:490)
	TestShell::RunFileTest [0x0187D515+1333] (c:\chromium2\src\webkit\tools\test_shell\test_shell_win.cc:292)
	main [0x010F31E2+6930] (c:\chromium2\src\webkit\tools\test_shell\test_shell_main.cc:411)
	__tmainCRTStartup [0x018D54C8+424] (f:\dd\vctools\crt_bld\self_x86\crt\src\crtexe.c:586)
	mainCRTStartup [0x018D530F+15] (f:\dd\vctools\crt_bld\self_x86\crt\src\crtexe.c:403)
	BaseThreadInitThunk [0x76B43667+18]
	RtlInitializeExceptionChain [0x779F9E12+99]
	RtlInitializeExceptionChain [0x779F9DE5+54]

static_cast<AccessibilityScrollbar*>(obj)->scrollbar() is returning garbage. Investigating...

[Chris Guillory]

Created attachment 73027 [details]
Keep a referene to the scrollbar in accessibility scrollbar.

[Dumitru Daniliuc]

Chris, can you please review this patch? I'm not familiar with this code.

[chris fleizach]

Comment on attachment 73027 [details]
Keep a referene to the scrollbar in accessibility scrollbar.

View in context: https://bugs.webkit.org/attachment.cgi?id=73027&action=review

Otherwise looks ok.

> WebCore/ChangeLog:5
> +        Keep a referene to the scrollbar in accessibility scrollbar.

spelling

[Chris Guillory]

Created attachment 73098 [details]
Keep a reference to the scrollbar in accessibility scrollbar.

[chris fleizach]

Comment on attachment 73098 [details]
Keep a reference to the scrollbar in accessibility scrollbar.

r=me

[WebKit Commit Bot]

Comment on attachment 73098 [details]
Keep a reference to the scrollbar in accessibility scrollbar.

Clearing flags on attachment: 73098

Committed r71445: <http://trac.webkit.org/changeset/71445>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.