Date: Tue, 25 Jan 2005 14:04:45 -0800 From: Julian Elischer <julian@elischer.org> To: jose@hostarica.com Cc: Yan Yu <yanyu@CS.UCLA.EDU> Subject: Re: seg fault on kse_release () (fwd) Message-ID: <41F6C27D.3040302@elischer.org> In-Reply-To: <1106686056.4973.6.camel@jose.hostarica.net> 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> <1106686056.4973.6.camel@jose.hostarica.net>
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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 "freebsd-hackers-unsubscribe@freebsd.org"
>>>>
>>>>
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