Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753272Ab3IRTIL (ORCPT ); Wed, 18 Sep 2013 15:08:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:30812 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753188Ab3IRTIH (ORCPT ); Wed, 18 Sep 2013 15:08:07 -0400 From: Richard Guy Briggs To: linux-audit@redhat.com, linux-kernel@vger.kernel.org Cc: Richard Guy Briggs , Steve Grubb , Eric Paris , Konstantin Khlebnikov , Andrew Morton , Dan Duval , Chuck Anderson , Guy Streeter , Oleg Nesterov Subject: [PATCH 5/8] audit: efficiency fix 2: request exclusive wait since all need same resource Date: Wed, 18 Sep 2013 15:06:50 -0400 Message-Id: <5c2035525f6bf06dcaa24a5922071d2f4e4e495e.1379530867.git.rgb@redhat.com> In-Reply-To: <20130917152842.51158606ed46ec67b97b4448@linux-foundation.org> References: <20130917152842.51158606ed46ec67b97b4448@linux-foundation.org> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2238 Lines: 59 author: Dan Duval These and similar errors were seen on a patched 3.8 kernel when the audit subsystem was overrun during boot: udevd[876]: worker [887] unexpectedly returned with status 0x0100 udevd[876]: worker [887] failed while handling '/devices/pci0000:00/0000:00:03.0/0000:40:00.0' udevd[876]: worker [880] unexpectedly returned with status 0x0100 udevd[876]: worker [880] failed while handling '/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1' udevadm settle - timeout of 180 seconds reached, the event queue contains: /sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1 (3995) /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/INT3F0D:00 (4034) audit: audit_backlog=258 > audit_backlog_limit=256 audit: audit_lost=1 audit_rate_limit=0 audit_backlog_limit=256 The change below increases the efficiency of the audit code and prevents it from being overrun: Use add_wait_queue_exclusive() in wait_for_auditd() to put the thread on the wait queue. When kauditd dequeues an skb, all of the waiting threads are waiting for the same resource, but only one is going to get it, so there's no need to wake up more than one waiter. See: https://lkml.org/lkml/2013/9/2/479 Signed-off-by: Dan Duval Signed-off-by: Chuck Anderson Signed-off-by: Richard Guy Briggs --- kernel/audit.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/audit.c b/kernel/audit.c index 25fab2d..990d02f 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1061,7 +1061,7 @@ static unsigned long wait_for_auditd(unsigned long sleep_time) unsigned long timeout = sleep_time; DECLARE_WAITQUEUE(wait, current); set_current_state(TASK_UNINTERRUPTIBLE); - add_wait_queue(&audit_backlog_wait, &wait); + add_wait_queue_exclusive(&audit_backlog_wait, &wait); if (audit_backlog_limit && skb_queue_len(&audit_skb_queue) > audit_backlog_limit) -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/