Date: Tue, 25 Jan 2005 14:47:36 -0600 From: Jose Hidalgo Herrera <jose@hostarica.com> To: Yan Yu <yanyu@CS.UCLA.EDU> Cc: jose@hostarica.com Subject: Re: seg fault on kse_release () (fwd) Message-ID: <1106686056.4973.6.camel@jose.hostarica.net> In-Reply-To: <Pine.GSO.4.58.0501251028210.8888@panther.cs.ucla.edu> References: <Pine.GSO.4.58.0501241426470.2472@panther.cs.ucla.edu> <1106669661.9523.7.camel@jose.hostarica.net> <Pine.GSO.4.58.0501251028210.8888@panther.cs.ucla.edu>
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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);
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 "freebsd-hackers-unsubscribe@freebsd.org"
> >
--
Jose Hidalgo Herrera <jose@hostarica.com>
Corp. Hostarica
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