Commit f000cfdd authored Jun 12, 2013 by Oleg Nesterov Committed by Linus Torvalds Jun 12, 2013

audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE



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.

Thanks to Guy for fully investigating and explaining the problem.

(akpm: that'll cause the system to lock up on a non-preemptible
uniprocessor kernel)

(Guy: "Our customer was in fact running a uniprocessor machine, and they
reported a system hang.")

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Guy Streeter <streeter@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent ebf8d6c8

kernel/audit.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1056,7 +1056,7 @@ static inline void audit_get_stamp(struct audit_context *ctx,
		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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