threads/1938: gdb gives incorrect thread numbering and is unstable

[pje at haystack dot mit dot edu]

>Number:         1938
>Category:       threads
>Synopsis:       gdb gives incorrect thread numbering and is unstable
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    unassigned
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Tue May 03 20:38:00 UTC 2005
>Closed-Date:
>Last-Modified:
>Originator:     Phil Erickson
>Release:        6.1post-1.20040607.62rh
>Organization:
>Environment:
Red Hat Enterprise 4 distribution:

uname -a
Linux XXXX 2.6.9-5.EL #1 Wed Jan 5 19:22:18 EST 2005 i686 i686 i386 GNU/Linux
>Description:
When run on a multithreaded program, gdb gives impossibly large negative thread IDs.  Additionally, debugging the program often results in segfaults and other stack instabilities.
>How-To-Repeat:
Compile the attached program with:

cc -g -o test_threads test_threads.c -lpthread

Run it with:

gdb ./test_threads

The following output is seen (notice the negative thread IDs):

gdb ./test_threads
GNU gdb Red Hat Linux (6.1post-1.20040607.62rh)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-redhat-linux-gnu"...(no debugging symbols found)...Using host libthread_db library "/lib/tls/libthread_db.so.1".

(gdb) run
Starting program: /mnt1/workspace/pje/test_nuwa/prototypes/install/MidaswAnalysisDistribution/midasw_c/test_threads
(no debugging symbols found)...[Thread debugging using libthread_db enabled]
[New Thread -1207966016 (LWP 4600)]
(no debugging symbols found)...(no debugging symbols found)...[New Thread -1207972944 (LWP 4603)]
Launching threads..I am thread 1
[New Thread -1218462800 (LWP 4604)]
Main thread still alive
I am thread 2
I am thread 1
I am thread 2
I am thread 1

Program received signal SIGINT, Interrupt.
[Switching to Thread -1207966016 (LWP 4600)]
0x003c17a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
(gdb) quit
The program is running.  Exit anyway? (y or n) y

>Fix:
None!  (This needs to be fixed since essentially it has broken all ability to debug multithreaded programs)
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: application/octet-stream; name="test_threads.c"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="test_threads.c"

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