Bug 22159

Summary: xorg-x11-libX11 with pthread isn't thread safe in xcb_lock.c
Product: XCB Reporter: G_Besdo <gunnar>
Component: LibraryAssignee: xcb mailing list dummy <xcb>
Status: RESOLVED FIXED QA Contact: xcb mailing list dummy <xcb>
Severity: normal    
Priority: medium CC: eich, mat, sndirsch
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: Example code file for xcb_lock.c error

Description G_Besdo 2009-06-08 10:43:14 UTC 
Created attachment 26551 [details]
Example code file for xcb_lock.c error

tested with openSUSE 11.1
I use the xorg-x11-libX11 library 7.4-1.29, glibc library 2.9-2.11.1.

One thread use the XDrawPoints function to put pixel to the window.
An other thread waits with XNextEvent for an event.

Every time I produce some events the program stops.

Reproducible: Sometimes

Steps to Reproduce:
1. translate the xcb_Test.c with gcc -o xcb_Test xcb_Test.c -pthread
-I/usr/include/X11 -lX11
2. run the program xcb_Test
3. to tap some keys
Actual Results:  
Every time I produce some events the program stops with

xcb_lock.c:33: _XCBUnlockDisplay: Assertion
`xcb_get_request_sent(dpy->xcb->connection) == dpy->request' failed.
or
xcb_lock.c:77: _XGetXCBBuffer: Assertion `((int) ((xcb_req) - (dpy->request))
>= 0)' failed.

In the xorg-x11-libX11-7.4-1.29.src.rpm is the file xcb_lock.c.
The file has a line
#include <pthread.h>
but nothing is used. I can translate the file without this line.
Comment 1 Julien Danjou 2009-06-08 10:50:26 UTC 
I'm not very familiar with thread stuff, but don't you miss XInitThread?
Comment 2 G_Besdo 2009-06-08 11:06:15 UTC 
(In reply to comment #1)
> I'm not very familiar with thread stuff, but don't you miss XInitThread?
> 
yes it was my mistake.

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