Bug 26832

Summary:	[bisected glx]: assert triggered by kwin, when glxCreateWindow is called with NULL attrib_list
Product:	Mesa	Reporter:	Magnus Kessler <Magnus.Kessler>
Component:	GLX	Assignee:	mesa-dev
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	medium
Version:	git
Hardware:	All
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	proposed fix

Description Magnus Kessler 2010-03-01 22:44:44 UTC

KDE's kwin calls glxCreateWindow with NULL as the attrib_list parameter when it sets up OpenGL based compositing. Since Mesa commit 706fffbff59be0dc884e1938f1bdf731af1efa3e this triggers an assert in CreateDrawable (glx_pbuffer.c:382), and the application crashes.

The man page for glxCreateWindow states explicitly that NULL is allowed to be passed as a value to the attrib_list parameter (http://www.opengl.org/sdk/docs/man/xhtml/glXCreateWindow.xml).

Comment 1 Magnus Kessler 2010-03-01 22:50:14 UTC

Created attachment 33677 [details] [review]
proposed fix

On closer inspection it appears that the variable "data" in glx_puffer.c CreateDrawable is essentially unused. Removing this variable should fix the issue of copying data from NULL, which commit 706fffbff59be0dc884e1938f1bdf731af1efa3e tried to guard against.

Comment 2 Brian Paul 2010-03-02 06:38:01 UTC

The proposed fix is incorrect.  We need to append the attrib_list information to the protocol request.  I'm replacing the assertion with a conditional.  See commit 44f6bb1ddf2ffda93a8f1ecf3eca3f051939482b on master and eede72b0f92ae49ed8c22f3210e615108a5e2b0a on the 7.7 branch.

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