Re: [PATCH 3/5] Use copy_wait_opts_to_user() in do_wait()

[Oleg Nesterov <oleg@redhat.com>]

Damn. I am sorry for the huge delay. Finally I have read this series
carefully.

On 05/11, Vitaly Mayatskikh wrote:
>
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -1600,8 +1600,6 @@ end:
>  	__set_current_state(TASK_RUNNING);
>  	remove_wait_queue(&current->signal->wait_chldexit,&wait);
>  	if (wo->wo_info) {
> -		struct siginfo __user *infop = wo->wo_info;
> -
>  		if (retval > 0)
>  			retval = 0;
>  		else {
> @@ -1610,18 +1608,7 @@ end:
>  			 * we would set so the user can easily tell the
>  			 * difference.
>  			 */
> -			if (!retval)
> -				retval = put_user(0, &infop->si_signo);
> -			if (!retval)
> -				retval = put_user(0, &infop->si_errno);
> -			if (!retval)
> -				retval = put_user(0, &infop->si_code);
> -			if (!retval)
> -				retval = put_user(0, &infop->si_pid);
> -			if (!retval)
> -				retval = put_user(0, &infop->si_uid);
> -			if (!retval)
> -				retval = put_user(0, &infop->si_status);
> +			retval = copy_wait_opts_to_user(wo, 0, 0, 0, 0, 0, 0);

This looks wrong.

copy_wait_opts_to_user()->getrusage() will OOPS if ->wo_rusage != NULL,
because we pass p == NULL.

Easy to fix, but I am not sure what is the most clean fix...

Oleg.