Bug 70647 – Common but unreproducible crash under [ScrollbarPartAnimation setCurrentProgress:]

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[Beth Dakin]

There have been number of occurrences of a crash while animating scrollbars, though no one has been able to find reproducible steps or catch it in the debugger. The stack trace is pasted below. It appears that the FrameView has been destroyed. There is already code in place that cancels all scrollbar animations when FrameViews are destroyed, so somehow that code must be circumvented in these rare occurrences of the crash.

<rdar://problem/9542018>

0   ???                           	0000000000 0 + 0
1   com.apple.WebCore             	0x993fcdbb non-virtual thunk to WebCore::FrameView::invalidateScrollbarRect(WebCore::Scrollbar*, WebCore::IntRect const&) + 107
2   com.apple.WebCore             	0x98d60102 WebCore::Scrollbar::invalidateRect(WebCore::IntRect const&) + 44
3   com.apple.WebCore             	0x9952e1f9 -[ScrollbarPartAnimation setCurrentProgress:] + 265
4   com.apple.AppKit              	0x95f3fc8c -[NSAnimation(NSInternal) _advanceTimeWithTimer:] + 409
5   com.apple.Foundation          	0x973dc373 __NSFireTimer + 166
6   com.apple.CoreFoundation      	0x976ee256 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 22
7   com.apple.CoreFoundation      	0x976edbe7 __CFRunLoopDoTimer + 743
8   com.apple.CoreFoundation      	0x976ccce0 __CFRunLoopRun + 1888
9   com.apple.CoreFoundation      	0x976cc1ec CFRunLoopRunSpecific + 332
10  com.apple.CoreFoundation      	0x976cc098 CFRunLoopRunInMode + 120
11  com.apple.HIToolbox           	0x90007487 RunCurrentEventLoopInMode + 318
12  com.apple.HIToolbox           	0x9000edc3 ReceiveNextEventCommon + 381
13  com.apple.HIToolbox           	0x9000ec32 BlockUntilNextEventMatchingListInMode + 88
14  com.apple.AppKit              	0x95d648ec _DPSNextEvent + 678
15  com.apple.AppKit              	0x95d64159 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 113
16  com.apple.AppKit              	0x95d604cb -[NSApplication run] + 904
17  com.apple.WebKit2             	0x97cdf198 RunLoop::run() + 56
18  com.apple.WebKit2             	0x97d063b0 WebKit::WebProcessMain(WebKit::CommandLine const&) + 628
19  com.apple.WebKit2             	0x97cf1629 WebKitMain + 309
20  com.apple.WebProcess          	0x00035dfd 0x35000 + 3581

[Beth Dakin]

Created attachment 112019 [details]
Patch

[Beth Dakin]

Committed change with revision 98178.