From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Guy Streeter <streeter@redhat.com>,
Eric Paris <eparis@redhat.com>,
David Woodhouse <dwmw2@infradead.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE
Date: Fri, 31 May 2013 19:10:25 +0200 [thread overview]
Message-ID: <20130531171025.GA32387@redhat.com> (raw)
In-Reply-To: <20130529145933.6e02f8379cf20b9c7ef30977@linux-foundation.org>
On 05/29, Andrew Morton wrote:
>
> On Fri, 24 May 2013 19:39:25 +0200 Oleg Nesterov <oleg@redhat.com> 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@redhat.com>
>
> And what did Guy report? "that looks screwy"? "my machine locked up"?
He also investigated the problem and provided the detailed explanation ;)
Oleg.
prev parent reply other threads:[~2013-05-31 17:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-24 17:39 [PATCH] audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE Oleg Nesterov
2013-05-24 17:41 ` Oleg Nesterov
2013-05-29 21:59 ` Andrew Morton
2013-05-29 22:08 ` Guy Streeter
2013-05-31 17:10 ` Oleg Nesterov [this message]
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