Bug 104504

Summary: [BlackBerry] Webkit crashes sometimes (even though very rarely) when deleting a webview
Product: WebKit Reporter: Charles Wei <charles.wei>
Component: WebKit BlackBerryAssignee: Charles Wei <charles.wei>
Status: RESOLVED FIXED    
Severity: Major CC: anilsson, logingx, mifenton, rwlbuis, staikos, tonikitoo, webkit.review.bot, yong.li.webkit
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch
none
Patch none

Charles Wei
Reported 2012-12-09 20:05:51 PST
Internal tracking number: 261567 When deleting a webview, the webkit thread will send a sync message to userInterfaceThread to delete handlers, including the viewport accessor. But the UserInterfaceThread could be doing a blit after it has deleted the viewport accessor and before the webkit thread gets the time slot to resume it's operation to clean up the webview, which leaves a very short time that viewport accessor of a webpage has been deleted while the webpage is still in the process of deleting, and the viewport accessor is referenced in the UserInterfaceThread when blitting contents. So we need to check if the viewport accessor is NULL before using it in the BackingStore code.
Attachments
Patch (2.92 KB, patch)
2012-12-09 20:11 PST, Charles Wei 		no flags
DetailsFormatted DiffDiff
Patch (3.06 KB, patch)
2012-12-09 23:09 PST, Charles Wei 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Charles Wei
Comment 1 2012-12-09 20:11:02 PST
Created attachment 178461 [details] Patch
Charles Wei
Comment 2 2012-12-09 20:12:05 PST
Comment on attachment 178461 [details] Patch Already reviewed and approved by George Staikos offline. Commit it.
Arvid Nilsson
Comment 3 2012-12-09 21:25:24 PST
This patch is not quite right, see comment in PR #261257
Arvid Nilsson
Comment 4 2012-12-09 21:25:42 PST
(In reply to comment #3) > This patch is not quite right, see comment in PR #261257 Uh, 261567
Charles Wei
Comment 5 2012-12-09 21:27:22 PST
Ok, stopped committing. will fix .
Charles Wei
Comment 6 2012-12-09 23:09:22 PST
Created attachment 178478 [details] Patch
Charles Wei
Comment 7 2012-12-09 23:23:00 PST
With the internal bug fix for 261671, this seems less likely to happen. But it doesn't hurt to have this fix just in case there's other code path that might reach here.
Arvid Nilsson
Comment 8 2012-12-10 04:51:45 PST
(In reply to comment #7) > With the internal bug fix for 261671, this seems less likely to happen. But it doesn't hurt to have this fix just in case there's other code path that might reach here. I agree, checking for null when something can be null is good.
Rob Buis
Comment 9 2012-12-10 05:01:40 PST
Comment on attachment 178478 [details] Patch LGTM.
Charles Wei
Comment 10 2012-12-10 05:26:14 PST
Comment on attachment 178478 [details] Patch Commit.
WebKit Review Bot
Comment 11 2012-12-10 05:35:43 PST
Comment on attachment 178478 [details] Patch Clearing flags on attachment: 178478 Committed r137140: <http://trac.webkit.org/changeset/137140>
WebKit Review Bot
Comment 12 2012-12-10 05:35:47 PST
All reviewed patches have been landed. Closing bug.
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