From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: net/ipv4/fib_trie.c:1550 suspicious rcu_dereference_check() usage Date: Tue, 10 Mar 2015 09:52:26 -0700 Message-ID: <54FF214A.1040703@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "netdev@vger.kernel.org" , Olof Johansson To: Fabio Estevam , "David S. Miller" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53395 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752183AbbCJQwb (ORCPT ); Tue, 10 Mar 2015 12:52:31 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 03/10/2015 09:20 AM, Fabio Estevam wrote: > On Tue, Mar 10, 2015 at 1:19 AM, Fabio Estevam wrote: >> Hi, >> >> On a imx6sl-warp board running linux-next 20150306: >> >> root@imx6sl-warp:~# reboot >> >> The system is going down for reboot NOW!(ttymxc0) (Wed Feb 25 18:41:59 2015): >> INIT: Switching to runlevel: 6 >> INIT: Sending processes the TERM signal >> INIT: Sending processe Stopping syslogd/klogd: stopped syslogd (pid 301) >> stopped klogd (pid 304) >> done >> Deconfiguring network interfaces... [ 36.083246] >> [ 36.084753] =============================== >> [ 36.089026] [ INFO: suspicious RCU usage. ] >> [ 36.093217] 4.0.0-rc2-next-20150306-00003-g62c7037-dirty #2699 Not tainted > It seems that the issue is gone in linux-next 20150310. I found the bug. It was in "fib_trie: Only resize tnodes once instead of on each leaf removal in fib_table_flush", commit 7289e6dd. I had incorrectly used a rcu_dereference where I should have used an rtnl_dereference. The offending code was removed and replaced 4 days ago when "fib_trie: Add key vector to root, return parent key_vector in resize", commit 88bae714, was applied. - Alex