Re: seg fault on kse_release () (fwd)

[Julian Elischer]

Jose Hidalgo Herrera wrote:

The line causing the SEGFAULT is
rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);

Why?, because t is declared as:
int t;
then you say:
args for start_routine in pthread_create are located in the address: t

This will be what you want:
rc = pthread_create(&threads[t], NULL, PrintHello, (void *) & t);

probably we shouldn't crash the system however.. (it is crashing right?
that wasn't so clear to me).

You also have an error in this line:

printf("\n%d: Hello World!\n", threadid);

Since threadid is not an int, its a pointer

On Tue, 2005-01-25 at 10:31 -0800, Yan Yu wrote:

Hi, thanks a LOT for looking into this.
yes, that is exactly my output before the SEG fault happens (btw, i add
"if (p)" before
"p[id]++ ", the prob remains..
what confuses me is that, if the system is out of memory, then i should
see the error returned from pthread_create() or calloc(), but not SEG
fault, or i must have missed something?

Thanks,
yan

On Tue, 25 Jan 2005, Jose Hidalgo Herrera wrote:

I ran it into:
4.11-STABLE FreeBSD Wed Jan 19 15:23:33 CST 2005
What you find in
http://www1.cr.freebsd.org/~jose/stress.tgz
is the output of:
ktrace ./a.out > stress.txt

On Mon, 2005-01-24 at 14:27 -0800, Yan Yu wrote:

Hi, all,  I have a newbie Q:
   I am trying to use creating large number of threads and allocting
memory to stress the system.
My user program causes SEG fault in the kernel code, kse_release () in
kern_kse.c.
(it SEG fault before the system can be stressed;(

the stack when the SEG fault happens are:
#0  0x08064e54 in kse_release ()
#1  0x080531c4 in kse_sched_single ()
#2  0x00000000 in ?? ()

My simple program is:
I have a simple function to create threads:

#define NUM_THREADS     5000
#define THREADS_IN_ONE_PROCESS  5
#define BSIZE  500000
static int  cc;

void CreateThread(int n)
{
  assert( n <= NUM_THREADS );
  pthread_t threads[NUM_THREADS];
  int rc, t;
  for(t=0;t < n;t++){
     printf("#%d: Creating thread %d\n", cc, t);
     cc++;
     rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);
     if (rc){
        printf("ERROR; return code from pthread_create() is %d\n", rc);
     }
  }

  unsigned long id;
  char * p = (char *) calloc(BSIZE, sizeof(char) );
  if ( p == NULL )
  {
       fprintf(stderr, "calloc error\n");
  }
  while (1)
  {
       while (BSIZE <= (id = rand() / (RAND_MAX/BSIZE)));
       p[id] ++;
  }
}

void *PrintHello(void *threadid)
{
  printf("\n%d: Hello World!\n", threadid);
  CreateThread(THREADS_IN_ONE_PROCESS);
  pthread_exit(NULL);
}

int main (int argc, char *argv[])
{
  CreateThread(THREADS_IN_ONE_PROCESS);
}

The SEG fault happens after creating nearly 5000 threads.
and I use the default pthread.h coming w/ freeBSD 5.3
#define PTHREAD_KEYS_MAX                        256
#define PTHREAD_STACK_MIN                       (1 << 22)
#define PTHREAD_THREADS_MAX                     ULONG_MAX

Any idea on what might happen?

Many Thanks!
yan
_______________________________________________
freebsd-hackers@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
To unsubscribe, send any mail to "[EMAIL PROTECTED]"

_______________________________________________
freebsd-hackers@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
To unsubscribe, send any mail to "[EMAIL PROTECTED]"