Re: [PATCH] audit: wait_for_auditd() should useTASK_UNINTERRUPTIBLE

[Oleg Nesterov]

On 05/29, Andrew Morton wrote:
>
> On Fri, 24 May 2013 19:39:25 +0200 Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>
> > audit_log_start() does wait_for_auditd() in a loop until
> > audit_backlog_wait_time passes or audit_skb_queue has a room.
> >
> > If signal_pending() is true this becomes a busy-wait loop,
> > schedule() in TASK_INTERRUPTIBLE won't block.
>
> And that's game over for a uniprocessor non-preempt machine, yes?

If this task is rt, yes. Otherwise schedule() still does pick_next_task()
but this is obviously bad anyway. So I fully agree with "Cc: stable" you
added.

> > Reported-by: Guy Streeter <streeter@xxxxxxxxxx>
>
> And what did Guy report?  "that looks screwy"?  "my machine locked up"?

He also investigated the problem and provided the detailed explanation ;)

Oleg.

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