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* [Bug libgomp/28468]  New: OpenMP-parallelized program crashes when OMP_NUM_THREADS > 1
@ 2006-07-24 14:19 bruno at clisp dot org
  2006-11-07 14:36 ` [Bug libgomp/28468] " bruno at clisp dot org
                   ` (6 more replies)
  0 siblings, 7 replies; 8+ messages in thread
From: bruno at clisp dot org @ 2006-07-24 14:19 UTC (permalink / raw)
  To: gcc-bugs

Versions:
* gcc: gcc (GCC) 4.2.0 20060715 (experimental)
* cpu: AMD-K7 (i686)
* kernel: Linux 2.4.21-99 (SuSE 9.0)
* glibc: glibc-2.3.6 built with LinuxThreads, _not_ NPTL

Test program:
============================== omp-test1.c =======================
#include <stdlib.h>
#include <stdio.h>

/* A computational task whose duration depends on x.  */
int job (int x)
{
  int j = rand() % (100 + 10 * x);
  int i;

  for (i = j - 1; i > 0; i--)
    if (j % i == 0)
      break;

  return i;
}

int main (int argc, char *argv[])
{
  int n = 10000;

  int *mem = malloc (n * sizeof (int));
  int i;

  /* Because the tasks don't have all the same duration, a dynamic
     schedule is best.  */
  #pragma omp parallel for schedule(dynamic)
  for (i = 0; i < n; i++)
    mem[i] = job (i);

  for (i = 0; i < n; i++)
    printf ("mem[%d] = %d\n", i, mem[i]);

  return 0;
}
=====================================================================

$ gcc -fopenmp -Wall -O omp-test1.c

The single-threaded program runs fine:
$ unset OMP_NUM_THREADS; ./a.out
or
$ export OMP_NUM_THREADS=1; ./a.out

But with more than one thread it crashes:

$ export OMP_NUM_THREADS=2; ./a.out
Segmentation fault (core dumped)
$ gdb a.out core.26661
GNU gdb 6.4
Copyright 2005 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 "i686-pc-linux-gnu"...Using host libthread_db
library "/lib/libthread_db.so.1".

Core was generated by `./a.out'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from
/gfs/ibook/Volumes/ExtData/bin.x86-linux/gnu-inst-gcc/4.2-20060715/lib/gcc/i686-pc-linux-gnu/4.2.0/libgomp.so.1...done.
Loaded symbols for
/packages/gnu-inst-gcc/4.2-20060715/lib/gcc/i686-pc-linux-gnu/4.2.0/libgomp.so.1
Reading symbols from /lib/libpthread.so.0...done.
Loaded symbols for /lib/libpthread.so.0
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/librt.so.1...done.
Loaded symbols for /lib/librt.so.1
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
#0  gomp_iter_dynamic_next (pstart=0xbfffe9c4, pend=0xbfffe9c8)
    at ../../../gcc-4.2-20060715/libgomp/iter.c:189
189       start = ws->next;
(gdb) where
#0  gomp_iter_dynamic_next (pstart=0xbfffe9c4, pend=0xbfffe9c8)
    at ../../../gcc-4.2-20060715/libgomp/iter.c:189
#1  0x4001c8e8 in gomp_loop_dynamic_next (istart=0xbfffe9c4, iend=0xbfffe9c8)
    at ../../../gcc-4.2-20060715/libgomp/loop.c:248
#2  0x080486ed in main.omp_fn.0 ()
#3  0x0804861e in main ()
(gdb) print ws
$1 = (struct gomp_work_share *) 0x0


-- 
           Summary: OpenMP-parallelized program crashes when OMP_NUM_THREADS
                    > 1
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgomp
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bruno at clisp dot org
 GCC build triplet: i686-suse-linux-gnu
  GCC host triplet: i686-suse-linux-gnu
GCC target triplet: i686-suse-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28468


^ permalink raw reply	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2008-03-10 16:10 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2006-07-24 14:19 [Bug libgomp/28468] New: OpenMP-parallelized program crashes when OMP_NUM_THREADS > 1 bruno at clisp dot org
2006-11-07 14:36 ` [Bug libgomp/28468] " bruno at clisp dot org
2006-11-15  9:45 ` jakub at gcc dot gnu dot org
2006-11-15 13:39 ` bruno at clisp dot org
2007-02-07 13:35 ` jakub at gcc dot gnu dot org
2007-02-07 13:39 ` jakub at gcc dot gnu dot org
2007-10-23 15:41 ` rth at gcc dot gnu dot org
2008-03-10 16:10 ` jakub at gcc dot gnu dot org

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