From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756000Ab3FPWW5 (ORCPT ); Sun, 16 Jun 2013 18:22:57 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46380 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755726Ab3FPWI4 (ORCPT ); Sun, 16 Jun 2013 18:08:56 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Linus Torvalds" , "Eric Paris" , "Al Viro" , "Guy Streeter" , "Oleg Nesterov" Date: Sun, 16 Jun 2013 23:01:38 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [73/83] audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.101 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.47-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov commit f000cfdde5de4fc15dead5ccf524359c07eadf2b upstream. 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 Reported-by: Guy Streeter Cc: Eric Paris Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context, indentation] Signed-off-by: Ben Hutchings --- kernel/audit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1167,7 +1167,7 @@ struct audit_buffer *audit_log_start(str /* Wait for auditd to drain the queue a little */ 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 &&