Bug 7186

Summary: Can't handle BIG-REQUESTS as big as advertised
Product: xorg Reporter: Jamey Sharp <jamey>
Component: Server/GeneralAssignee: Eric Anholt <eric>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: high CC: chris
Version: unspecified   
Hardware: All   
OS: All   
Whiteboard:
i915 platform: i915 features:
Bug Depends on:    
Bug Blocks: 8888    

Description Jamey Sharp 2006-06-11 10:35:35 UTC 
It appears that X servers up to at least X.org 7.0 and back as far as the MacOS
X release of XFree86 4.4 can't handle BIG-REQUESTS that are as big as they
advertise support for.

http://lists.freedesktop.org/archives/xcb/2006-June/001695.html

The symptom: if a client makes a request that is bigger than 1/4th the limit
advertised in the BigRequestsEnable reply, the X server closes the connection.
Here is an XCB-based test program that demonstrates the bug:

http://minilop.net/svn/jamey/trunk/test/xlib/big-crash.c

From inspection of server sources, I speculate that the bug is in os/io.c, in
the ReadRequestFromClient function. I haven't been able to dig deeper than that
because that function scares me, but the comment in that file saying, "Watch
out: needed sometimes counts bytes and sometimes counts CARD32's," seems suspicious.
Comment 1 Adam Jackson 2006-10-12 18:38:07 UTC 
Ick.  Marking as blocker.
Comment 2 Daniel Stone 2007-02-27 01:32:30 UTC 
Sorry about the phenomenal bug spam, guys.  Adding xorg-team@ to the QA contact so bugs don't get lost in future.
Comment 3 Adam Jackson 2007-04-08 13:37:37 UTC 
Move to 7.3 tracker.
Comment 4 Eric Anholt 2007-08-31 13:24:27 UTC 
Pushed to master, awaiting cherry-pick to stable.
Comment 5 Alan Coopersmith 2007-11-05 18:33:09 UTC 
*** Bug 10672 has been marked as a duplicate of this bug. ***

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