Date: Tue, 25 Jan 2005 14:15:25 -0800 (PST) From: Yan Yu <yanyu@CS.UCLA.EDU> To: Julian Elischer <julian@elischer.org> Cc: jose@hostarica.com Subject: Re: seg fault on kse_release () (fwd) Message-ID: <Pine.GSO.4.58.0501251412590.22219@panther.cs.ucla.edu> In-Reply-To: <41F6C27D.3040302@elischer.org> References: <Pine.GSO.4.58.0501241426470.2472@panther.cs.ucla.edu> <Pine.GSO.4.58.0501251028210.8888@panther.cs.ucla.edu> <41F6C27D.3040302@elischer.org>
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> >
> >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).
the user land prog SEG fault itself,
it did not bring down the system though,
i am not sure my reply to jose was sent out (i am in this mailing list
yet), i tried what jose suggested, the seg fault remains..
thanks,
yan
>
> >
> >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"
> >>>>
> >>>>
>
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