Re: [PATCH] selinux_bprm_committed_creds: use __wake_up_parent()

[Andrew Morton <akpm@linux-foundation.org>]

On Fri, 3 Jul 2009 11:23:11 +0200 Oleg Nesterov <oleg@redhat.com> wrote:

> (depends on ptrace-__ptrace_detach-do-__wake_up_parent-if-we-reap-the-tracee.patch
>  which exports __wake_up_parent)
> 
> Spotted by Valdis.Kletnieks@vt.edu.
> 
> selinux_bprm_committed_creds() should not play with ->wait_chldexit, now
> that __wake_up_parent() is exported change the code to use this helper.

That's a bit vague.  Why shouldn't it play with wait_chldexit?  What
changed to make that wrong?

Is this a -mm fix?  If so, which -mm patch introduced the problem?

If not, how come the crash isn't being reported in mainline?

Confused.

> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> 
> --- WAIT/security/selinux/hooks.c~SEL_WAKE_PARENT	2009-06-16 17:01:42.000000000 +0200
> +++ WAIT/security/selinux/hooks.c	2009-07-03 11:15:08.000000000 +0200
> @@ -2404,7 +2404,7 @@ static void selinux_bprm_committed_creds
>  	/* Wake up the parent if it is waiting so that it can recheck
>  	 * wait permission to the new task SID. */
>  	read_lock(&tasklist_lock);
> -	wake_up_interruptible(&current->real_parent->signal->wait_chldexit);
> +	__wake_up_parent(current, current->real_parent);
>  	read_unlock(&tasklist_lock);
>  }
>