Bug 196545 - pthread_create fails on s390/zSeries after 103 new threads
Summary: pthread_create fails on s390/zSeries after 103 new threads
Alias: None
Product: Red Hat Enterprise Linux 3
Classification: Red Hat
Component: glibc
Version: 3.0
Hardware: s390
OS: Linux
Target Milestone: ---
Assignee: Jakub Jelinek
QA Contact: Brian Brock
Depends On:
TreeView+ depends on / blocked
Reported: 2006-06-24 14:24 UTC by Chris Ruhl
Modified: 2007-11-30 22:07 UTC (History)
0 users

Clone Of:
Last Closed: 2006-06-26 07:38:26 UTC

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Description Chris Ruhl 2006-06-24 14:24:23 UTC
We are experiencing a problem that is unique to the Linux S390 systems running
RedHat (xSeries running RedHat are ok).  When the workloads start they do a
bunch of  pthread_creates (various by type of workload started) .  Each thread
will run until it is terminated by the user or an error is encountered.  When
attempting to create the 103 thread, pthread_create fails with a return code of
12 (ENOMEM).  I've attached a 'c' program that reproduces the failure.  The
function that is invoked on the pthread_create is not longed lived (just a
simple loop).  I compile it with gcc -lpthread -g -o mythread mythread.c . 

  #define _OPEN_THREADS
#define _POSIX_C_SOURCE 3
#define __EXTENSIONS__
#include <pthread.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

typedef struct my_struct
   pthread_t run_id;
} my_struct;

void *runit(void *arg);

int main(int argc, char **argv)
  int            rc = 0;
  register unsigned int lp_cnt;
  my_struct      parm;
  pthread_attr_t attr;
  pthread_t      thread_id = pthread_self();

  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

  for(lp_cnt = 1; lp_cnt < 0xffff; lp_cnt++)
     parm.run_id = lp_cnt;
     rc = pthread_create(&thread_id, &attr, runit, (void *)&parm);

     if (rc != 0)
       printf("bad rc %d from pthread_create on run_id %d\n", rc, lp_cnt);

void *runit(void *arg)
   my_struct *parm = (my_struct *)arg;
   register unsigned int lp_cnt;

   printf("runit started for run_id %d\n", parm->run_id);
   for(lp_cnt = 0; lp_cnt < 0xffffffff; lp_cnt++);
   printf("runit ended for run_id %d\n", parm->run_id);

Comment 1 Jakub Jelinek 2006-06-26 07:38:26 UTC
The testcase is terribly buggy, e.g. parm is a shared variable while you are
clearly relying on it being thread local.  Also, you don't tweak the thread stack
size in any way (no pthread_attr_setstacksize call), so you get the default
thread stack size, which is huge and on s390 which has only 2GB of address space
you quickly fill in the whole address space with the thread stack mappings.

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