Bug 43807 – REGRESSION (r64816-r64889): Crash in WebCore::AccessibilityRenderObject

• Component: Accessibility
• Status: RESOLVED FIXED

[Kevin M. Dean]

Whenever I press Command-Control-d over some text to bring up the floating dictionary window, Webkit gets the spinning wheel and crashes.


Process:         Safari [705]
Path:            /Applications/WebKit.app/Contents/MacOS/WebKit
Identifier:      org.webkit.nightly.WebKit
Version:         r65052 (65052)
Code Type:       PPC (Native)
Parent Process:  launchd [110]

Date/Time:       2010-08-10 13:24:58.447 -0400
OS Version:      Mac OS X 10.5.8 (9L30)
Report Version:  6
Anonymous UUID:  F41C1802-6457-4B49-A738-107FEBA3B7F7

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000000
Crashed Thread:  0

Thread 0 Crashed:
0   com.apple.WebCore             	0x01497e18 WebCore::AccessibilityRenderObject::visiblePositionForPoint(WebCore::IntPoint const&) const + 408
1   com.apple.WebCore             	0x0148c164 -[AccessibilityObjectWrapper accessibilityAttributeValue:forParameter:] + 2532
2   ....DictionaryServiceComponent	0x1d370ff4 DSAXGetTextOrigin + 1028
3   ....DictionaryServiceComponent	0x1d370908 DSAXGetTextUnderMouse + 432
4   ....DictionaryServiceComponent	0x1d36fb70 DSGetTextUnderMouse + 1024
5   ....DictionaryServiceComponent	0x1d3702cc DSInitializeMessageReceiving + 616
6   com.apple.CoreFoundation      	0x920e9258 __CFMessagePortPerform + 324
7   com.apple.CoreFoundation      	0x92109630 CFRunLoopRunSpecific + 2480
8   com.apple.HIToolbox           	0x90c09b14 RunCurrentEventLoopInMode + 264
9   com.apple.HIToolbox           	0x90c09938 ReceiveNextEventCommon + 412
10  com.apple.HIToolbox           	0x90c09778 BlockUntilNextEventMatchingListInMode + 84
11  com.apple.AppKit              	0x93151244 _DPSNextEvent + 596
12  com.apple.AppKit              	0x93150bfc -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 112
13  com.apple.Safari              	0x000191c4 0x1000 + 98756
14  com.apple.AppKit              	0x9314a89c -[NSApplication run] + 744
15  com.apple.AppKit              	0x9311b298 NSApplicationMain + 440
16  com.apple.Safari              	0x0000b7c8 0x1000 + 42952

[chris fleizach]

interesting. i think this is a dupe of other bugs (in radar, not yet in webkit)

it looks like dictionary services is using accessibility to get text, which is new to me.

Kevin, can you attach the whole crash report. we might be able to get line numbers out of it

[Kevin M. Dean]

Created attachment 64130 [details]
Full Crash Log

[chris fleizach]

looks like DictionaryServices changed and no longer uses that method, so this crash report only exists in leopard. i suspect that the problem still exists in webkit however. there's a lot of potential places we'd be accessing a null pointer in that method.

[Kevin M. Dean]

Any update on this crash bug? Still around with the latest webkit and Safari 5.0.2.

[chris fleizach]

(In reply to comment #4)
> Any update on this crash bug? Still around with the latest webkit and Safari 5.0.2.

I'm testing right now on 10.6.4 and 5.0.2 and i'm not running into a crash. do you have a website that this always happens on? can you give any other info

[Kevin M. Dean]

You previously mentioned that the crash only exists in Leopard, so I would expect 10.6.4 to be fine based on that.

The crash is with the dictionary function and happens anywhere regardless of which web site it's on.

[chris fleizach]

(In reply to comment #6)
> You previously mentioned that the crash only exists in Leopard, so I would expect 10.6.4 to be fine based on that.
> 
> The crash is with the dictionary function and happens anywhere regardless of which web site it's on.

sorry meant to say latest 10.5

[Kevin M. Dean]

Are you making sure you're running Webkit. Straight Safari 5.0.2 under 10.5.8 works fine. It's the latest Webkit in that combination that crashes on me.

[chris fleizach]

regression from
https://bugs.webkit.org/show_bug.cgi?id=43632

[chris fleizach]

<rdar://problem/8421449>

[chris fleizach]

Created attachment 67369 [details]
patch

[Eric Seidel (no email)]

Comment on attachment 67369 [details]
patch

Wouldn't it be easier just to change the later line to use render() instead of renderBoxModelObject()?

[chris fleizach]

http://trac.webkit.org/changeset/67390