On Mon, 10 Jun 2013 18:56:38 -0300 "Raphael S. Carvalho" 
<raphael.sc...@gmail.com> wrote:

> This patch shouldn't be applied if those branches must only be taken when
> the pid_allocation(PIDNS_HASH_ADDING) flag was turned off.

Well yes - hopefully this is the case.  Otherwise we're missing some
rather important-looking wakeups.


> Otherwise, we must turn the PIDNS_HASH_ADDING flag (1U << 31) off
> before getting into the switch-cases.
> 
> ...
>
> --- a/kernel/pid.c
> +++ b/kernel/pid.c
> @@ -263,7 +263,10 @@ void free_pid(struct pid *pid)
>               struct upid *upid = pid->numbers + i;
>               struct pid_namespace *ns = upid->ns;
>               hlist_del_rcu(&upid->pid_chain);
> -             switch(--ns->nr_hashed) {
> +
> +             /* We must turn the PIDNS_HASH_ADDING flag off to
> +                get the actual value of nr_hashed */
> +             switch ((--ns->nr_hashed) & ~(PIDNS_HASH_ADDING)) {
>               case 1:
>                       /* When all that is left in the pid namespace
>                        * is the reaper wake up the reaper.  The reaper

Eric, can you please take a look?  Presumably and hopefully
PIDNS_HASH_ADDING cannot be set here, but what guarantees this?

Hopefully we can fix this one by adding the missing comment.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to