threads/119920: fork broken in libpthread

[Julian Elischer]

Landon Fuller wrote:
> 
> On Jan 31, 2008, at 10:44, Julian Elischer wrote:
> 
>> the releng 6 and releng 7 versions of this patch are at:
>>
>> http://www.freebsd.org/~julian/kse-6.diff
>>
>> and
>>
>> http://www.freebsd.org/~julian/kse-7.diff
>>
>>
>> but the one for 7 is just speculative.
>>
>> I don't have a 7.x system to test.
>>
>>
>> Landon, what is your test case?
>>
> 
> Inlined below. On our 8-core 6.3 system without this patch, the fork() 
> threads wedge and spin in <2 minutes. With the patch, works as expected.
> 
> #include <sys/types.h>
> #include <unistd.h>
> #include <pthread.h>
> 
> void *forker (void *arg) {
>         while (1) {
>                 pid_t pid = fork();
>                 if (pid == 0) {
>                         exit(0);
>                 } else if (pid > 0) {
>                         int status;
>                         waitpid(pid, &status, 0);
>                 } else {
>                         printf("Fork failed\n");
>                         abort();
>                 }
>         }
> }
> 
> int main(void) {
>         int i = 0;
>         for (i = 0; i < 4; i++) {
>                 pthread_t thr;
>                 pthread_create(&thr, NULL, forker, NULL);
>                 pthread_detach(thr);
>         }
> 
>         while(1)
>                 sleep(1000);
> }


great..

is there anyone with a 7.0 MP system, that can confirm that this 
happens in 7 and that the patch (above) fixes it?