From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: 2.6.25-rc2-mm1 - several bugs and a crash Date: Wed, 20 Feb 2008 22:50:09 +0100 Message-ID: <47BCA091.80009@trash.net> References: <20080216002522.9c4bd0fb.akpm@linux-foundation.org> <47BC982C.7050402@imap.cc> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Andrew Morton , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org, coreteam@netfilter.org To: Tilman Schmidt Return-path: In-Reply-To: <47BC982C.7050402@imap.cc> Sender: netfilter-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Tilman Schmidt wrote: > Still, X came up fine, I could log in (Gnome feeling subjectively > a bit sluggish), call up a web page from the Internet in Firefox, > and start perusing the logs, when the whole system froze: neither > mouse nor keyboard would react anymore, and only the Wind^Wreset > button would put me back in control. After rebooting into the > previous, non-mm kernel I found this in the syslog: > > Feb 20 17:22:40 xenon kernel: [ 48.180297] BUG: using smp_processor_id() in preemptible [00000000] code: ntpdate/3562 > Feb 20 17:22:40 xenon kernel: [ 48.180297] caller is __nf_conntrack_find+0x9b/0xeb [nf_conntrack] > Feb 20 17:22:40 xenon kernel: [ 48.180297] Pid: 3562, comm: ntpdate Not tainted 2.6.25-rc2-mm1-testing #1 > Feb 20 17:22:40 xenon kernel: [ 48.180297] [] debug_smp_processor_id+0x99/0xb0 > Feb 20 17:22:40 xenon kernel: [ 48.180297] [] __nf_conntrack_find+0x9b/0xeb [nf_conntrack] I guess the cause for this is a combination of preemtible RCU and conntrack using RCU since 2.6.25-rc. Using NF_CT_STAT_INC_ATOMIC should fix it, but I'd prefer to have a fix that doesn't increase overhead when regular RCU is used. I'll see if I can find a better way to fix this tommorrow.