From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: Locking bug in 3.0.25, IPv6. Date: Mon, 26 Mar 2012 11:41:52 -0700 Message-ID: <4F70B870.4090900@candelatech.com> References: <4F709EAA.6040700@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: netdev Return-path: Received: from mail.candelatech.com ([208.74.158.172]:46501 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933050Ab2CZSmB (ORCPT ); Mon, 26 Mar 2012 14:42:01 -0400 Received: from [192.168.100.111] (firewall.candelatech.com [70.89.124.249]) (authenticated bits=0) by ns3.lanforge.com (8.14.2/8.14.2) with ESMTP id q2QIfqvg027422 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 26 Mar 2012 11:41:53 -0700 In-Reply-To: <4F709EAA.6040700@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: On 03/26/2012 09:51 AM, Ben Greear wrote: > Has anyone seen this in 3.0.25? My kernel has some other patches > applied, but we did not see this before 3.0.24. > > BUG: sleeping function called from invalid context at /home/greearb/git/linux-3.0.dev.y/mm/memory.c:3904 Just FYI: This happens in un-modified kernels...seems to have been introduced (or made more visible) somewhere between 3.0.19 and 3.0.23. I'm bisecting it now... Thanks, Ben > > ================================================ > [ BUG: lock held when returning to user space! ] > ------------------------------------------------ > ip/6696 is leaving the kernel with locks still held! > 1 lock held by ip/6696: > #0: (rcu_read_lock){.+.+..}, at: [] rcu_read_lock+0x0/0x35 [ipv6] > in_atomic(): 0, irqs_disabled(): 0, pid: 6694, name: ip > INFO: lockdep is turned off. > Pid: 6694, comm: ip Tainted: G C 3.0.25+ #1 > Call Trace: > [] __might_sleep+0x111/0x115 > [] might_fault+0x2f/0x9e > [] ? copy_from_user+0x2a/0x2c > [] ? might_fault+0x4e/0x9e > [] move_addr_to_user+0x21/0x8e > [] __sys_recvmsg+0x17f/0x21e > [] ? up_read+0x1e/0x36 > [] ? fcheck_files+0xb7/0xee > [] ? fget_light+0x35/0xac > [] ? remove_vma+0x7a/0x82 > [] sys_recvmsg+0x3d/0x5b > [] system_call_fastpath+0x16/0x1b > -- Ben Greear Candela Technologies Inc http://www.candelatech.com