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

From: Andrew Morton
Date: Wed May 29 2013 - 17:59:41 EST


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?

> Reported-by: Guy Streeter <streeter@xxxxxxxxxx>

And what did Guy report? "that looks screwy"? "my machine locked up"?

> @@ -1056,7 +1056,7 @@ static inline void audit_get_stamp(struc
> static void wait_for_auditd(unsigned long sleep_time)
> {
> DECLARE_WAITQUEUE(wait, current);
> - set_current_state(TASK_INTERRUPTIBLE);
> + set_current_state(TASK_UNINTERRUPTIBLE);
> add_wait_queue(&audit_backlog_wait, &wait);
>
> if (audit_backlog_limit &&
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