Bug 82866

Summary: Xserver crashes in Mesa context cleanup handling
Product: [Retired] Red Hat Raw Hide Reporter: Ezra Peisach <epeisach>
Component: XFree86Assignee: Mike A. Harris <mharris>
Status: CLOSED RAWHIDE QA Contact: David Lawrence <dkl>
Severity: high Docs Contact:
Priority: medium    
Version: 1.0   
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Hardware: i386   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2003-01-31 07:54:42 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
Patch to prevent dereferencing NULL pointer none

Description Ezra Peisach 2003-01-27 22:53:57 UTC 
From Bugzilla Helper:
User-Agent: Mozilla/4.79C-SGI [en] (X11; I; IRIX 6.5 IP32)

Description of problem:
I have an application that opens a GL context - but then due to a bug - dies.
The Xserver 
seeing that the application has closed, attempts to cleanup memory. 

In xc/extras/Mesa/src/tnl a memory cache is maintained of the last freed memory.
_tnl_DestroyContext will call _tnl_free_immediate with a pointer to this memory
- which may
be a NULL pointer.

_tnl_free_immediate assumes that the pointer passed to it is valid.

There are two possible fixes - either  in tnl_free_immediate - to detect a NULL
pointer or _tnl_DestroyContext.

Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
1. Run a specific program I cannot send - but I will work on a minimal coding
example.
2.
3.
    

Actual Results:  X server crashes on program exit

Expected Results:  X server should have continued running

Additional info:

See attached patch
Comment 1 Ezra Peisach 2003-01-27 22:55:26 UTC 
Created attachment 89625 [details]
Patch to prevent dereferencing NULL pointer
Comment 2 Mike A. Harris 2003-01-31 07:54:42 UTC 
Fixed in XFree86 CVS, will be in my next build.

 811. Fix a null dereference in Mesa that can cause an X server crash at
      client exit (#A.1548, Ezra Peisach).