Re: gdb/286: Gdb is currently not able to debug a pthread linked application on linux-mipsel targets.

[Daniel Jacobowitz <drow at mvista dot com>]

The following reply was made to PR gdb/286; it has been noted by GNATS.

From: Daniel Jacobowitz <drow@mvista.com>
To: thaber@tee.toshiba.de
Cc: gdb-gnats@sources.redhat.com
Subject: Re: gdb/286: Gdb is currently not able to debug a pthread linked application on linux-mipsel targets.
Date: Mon, 21 Jan 2002 09:12:32 -0500

 This is a bug in glibc.  It has been explained to the libc developers
 several times; see the archives of the libc-alpha list on
 sources.redhat.com.
 
 On Mon, Jan 21, 2002 at 12:07:43PM -0000, thaber@tee.toshiba.de wrote:
 > 
 > >Number:         286
 > >Category:       gdb
 > >Synopsis:       Gdb is currently not able to debug a pthread linked application on linux-mipsel targets.
 > >Confidential:   no
 > >Severity:       serious
 > >Priority:       medium
 > >Responsible:    unassigned
 > >State:          open
 > >Class:          sw-bug
 > >Submitter-Id:   net
 > >Arrival-Date:   Mon Jan 21 04:08:01 PST 2002
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     thaber@tee.toshiba.de
 > >Release:        5.1
 > >Organization:
 > >Environment:
 > config:               mipsel-unknown-linux-gnu
 > platform:           mipsel  (tx49 toshiba)
 > linux:                 Red Hat Linux release 7.0 (MIPS) Kernel 2.4.6 on 
 > a mips
 > compiler:          gcc version 2.95.3 20010315 (release)
 > 
 > 
 > 
 > >Description:
 > Hi all,
 > 
 > currently we are not able to debug a pthread linked application with gdb ...
 > 
 >      GNU gdb 5.1
 >     Copyright 2001 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 "mipsel-unknown-linux-gnu"...
 >     (gdb) break main
 >     Breakpoint 1 at 0x40091c
 >     (gdb) run
 >     Starting program: /home/teehab/DVB/Linux/Default/test2
 >     [New Thread 1024 (LWP 380)]
 > 
 >     Program received signal SIGTRAP, Trace/breakpoint trap.
 >     [Switching to Thread 1024 (LWP 380)]
 >     warning: Warning: GDB can't find the start of the function at
 >     0x40080000.
 > 
 >         GDB is unable to find the start of the function at 0x40080000
 >     and thus can't determine the size of that function's stack frame.
 >     This means that GDB may be unable to access that stack frame, or
 >     the frames below it.
 >         This problem is most likely caused by an invalid program counter or
 >     stack pointer.
 >         However, if you think GDB should simply search farther back
 >     from 0x40080000 for code which looks like the beginning of a
 >     function, you can increase the range of the search using the `set
 >     heuristic-fence-post' command.
 >     0x40080000 in ?? ()
 > 
 > 
 > 
 > When setting heuristic-fence-post to 20 the result is ...
 > 
 >     (gdb) break main
 >     Breakpoint 1 at 0x40091c
 >     (gdb) run
 >     Starting program: /home/teehab/DVB/Linux/Default/test2
 >     [New Thread 1024 (LWP 382)]
 > 
 >     Program received signal SIGTRAP, Trace/breakpoint trap.
 >     [Switching to Thread 1024 (LWP 382)]
 >     Cannot access memory at address 0x4007fffc
 > 
 > The test application compiled with 'gcc test.c -lpthread -o test'  :
 > 
 > 
 >     #include <pthread.h>
 > 
 > #define MAX_THREAD 40
 > 
 >     void* function(void*p)
 >     {
 >       while(1) printf("X%i",(int)p);
 >       return 0;
 >     }
 > 
 > 
 >     int main(int argc, char *argv[])
 >     {
 >       int i=0;
 > 
 >       pthread_t threadID=-1;
 > 
 >       for(i=0;i<MAX_THREAD;i++)
 >       {
 >        pthread_create(&threadID, NULL, function, (void*)i);
 >       }
 > 
 >       return 0;
 >     }
 > 
 >     Thanks for your help,
 > 
 >     tom haber
 > 
 > 
 > 
 > 
 > 
 > 
 > 
 > 
 > >How-To-Repeat:
 > 
 > >Fix:
 > 
 > >Release-Note:
 > >Audit-Trail:
 > >Unformatted:
 > 
 
 -- 
 Daniel Jacobowitz                           Carnegie Mellon University
 MontaVista Software                         Debian GNU/Linux Developer