On 08/06, Adrian Reber wrote:
>
> +struct pid *alloc_pid(struct pid_namespace *ns, int set_tid)
> {
> struct pid *pid;
> enum pid_type type;
> @@ -186,12 +186,35 @@ struct pid *alloc_pid(struct pid_namespace *ns)
> if (idr_get_cursor(&tmp->idr) > RESERVED_PIDS)
> pid_min = RESERVED_PIDS;
>
> - /*
> - * Store a null pointer so find_pid_ns does not find
> - * a partially initialized PID (see below).
> - */
> - nr = idr_alloc_cyclic(&tmp->idr, NULL, pid_min,
> - pid_max, GFP_ATOMIC);
> + if (set_tid) {
> + /*
> + * Also fail if a PID != 1 is requested
> + * and no PID 1 exists.
> + */
> + if ((set_tid >= pid_max) || ((set_tid != 1) &&
> + (idr_is_empty(&tmp->idr)))) {
too many parentheses ;) this is purely cosmetic, up to you, but to me
if (set_tid >= pid_max ||
(set_tid != 1 && idr_is_empty(&tmp->idr))) {
looks a bit more readable.
> + spin_unlock_irq(&pidmap_lock);
> + retval = -EINVAL;
> + goto out_free;
This doesn't look right, you need idr_preload_end() before goto out_free.
But I'd suggest to simply do
nr = -EINVAL;
if (set_tid < pid_max &&
(set_tid != 1 || idr_is_empty(&tmp->idr)))
nr = idr_alloc(&tmp->idr, NULL, set_tid,
set_tid + 1, GFP_ATOMIC);
...
this is more robust.
Oleg.
