Re: [PATCH 09/11] job control: reorganize wait_task_stopped()

[Oleg Nesterov]

On 05/12, Tejun Heo wrote:
>
>   int main(int argc, char **argv)
>   {
> 	  pid_t child, control;
>
> 	  child = fork();
> 	  if (!child)
> 		  while (1)
> 			  pause();
>
> 	  kill(child, SIGSTOP);
> 	  waitid(P_PID, child, NULL, WSTOPPED | WNOWAIT);
>
> 	  control = fork();
> 	  if (!control) {
> 		  while (1) {
> 			  kill(child, SIGCONT);
> 			  nanosleep(&ts1ms, NULL);
> 			  kill(child, SIGSTOP);
> 			  nanosleep(&ts1ms, NULL);

Damn, you are right, I think.

At first glance, do_wait() does

	wait_task_stopped();
	wait_task_continued();

and the state can be changed CONTINIUED -> STOPPED in between, right?
Or something else?

Thanks, for the explanation.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/