Bug 18465

Summary: X crashes when disabling compositing in kwin
Product: xorg Reporter: Gábor Lehel <illissius>
Component: * OtherAssignee: Xorg Project Team <xorg-team>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium CC: Magnus.Kessler
Version: 7.4 (2008.09)   
Hardware: x86 (IA32)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
X log
none
backtrace of the server crash
none
avoid calling DRIGetDrawableInfo with NULL pScreen none

Description Gábor Lehel 2008-11-10 05:41:30 UTC 
KWin in KDE4 has a shortcut to toggle compositing on and off. Sometimes (not always) when I toggle compositing off with this, X crashes. Dunno if this is a bug in kwin or X, so I'm reporting it in both places. Attaching the X log. There's a not-too-useful backtrace near the end.
Comment 1 Gábor Lehel 2008-11-10 05:42:19 UTC 
Created attachment 20179 [details]
X log
Comment 2 Gábor Lehel 2008-11-11 10:11:53 UTC 
A workaround for this was just committed to kwin: http://bugs.kde.org/show_bug.cgi?id=174782#c1 (includes what looks like more info about the bug itself)
Comment 3 Magnus Kessler 2008-11-14 11:13:04 UTC 
Created attachment 20310 [details]
backtrace of the server crash
Comment 4 Magnus Kessler 2008-11-14 11:17:48 UTC 
Created attachment 20311 [details] [review]
avoid calling DRIGetDrawableInfo with NULL pScreen

This patch adds an extra check for a NULL pScreen pointer into glxdri.c getDrawableInfo(), in line with an existing check for a NULL pDraw pointer.
Comment 5 Michel Dänzer 2008-11-14 12:28:40 UTC 
The patch is a hack and won't always help I'm afraid. The problem is that pDraw is a stale pointer.
Comment 6 Michel Dänzer 2009-09-01 01:54:06 UTC 
This should be fixed in xserver 1.6.3.901.

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