Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754894AbaDNPZr (ORCPT ); Mon, 14 Apr 2014 11:25:47 -0400 Received: from katalix.com ([82.103.140.233]:50872 "EHLO bert.katalix.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752083AbaDNPZo (ORCPT ); Mon, 14 Apr 2014 11:25:44 -0400 X-Greylist: delayed 396 seconds by postgrey-1.27 at vger.kernel.org; Mon, 14 Apr 2014 11:25:44 EDT Message-ID: <534BFC69.6080209@katalix.com> Date: Mon, 14 Apr 2014 16:19:05 +0100 From: James Chapman Organization: Katalix Systems Ltd User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Zhan Jianyu , davem@davemloft.net, edumazet@google.com, joe@perches.com CC: LKML , netdev@vger.kernel.org Subject: Re: [BUG] A panic caused by null pointer dereference aftering updating to References: In-Reply-To: X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Please send the complete oops message. Is this a regression? If so, do you know what the last kernel version was that worked? Thanks James On 14/04/14 14:33, Zhan Jianyu wrote: > When I tried to connect my VPN, I got a panic, saying > a NULL poiter dereference at 0x00000000000002c0 > > I came across this bug twice today, after updateing to > Linux-3.15-rc1. > > Below are some panic message(hand copy,not complete) > ===== > > Kernel panic - not syncing: Fatal exception in interupt > > RIP ip_queue_xmit+0x20/0x3e0 > Call Trace: > l2tp_xmit_skb+0x335/0x6c0 [l2tp_core] > ? skb_free_head+0x1e/0x80 > pppol2tp_xmit+0x141/0x210 [l2tp_ppp] > ppp_channel_push+0x50/0xd0 [ppp_generic] > ppp_write+0xa3/0xec [ppp_generic] > vfs_write > Sys_wirte > ? __audit_syscall_exit > system_call_fastpath > > ===== > > I've tried to figure it out. > I disassembled ip_queue_xmit, found that the null > dereference is caused by the first argument of > ip_queue_xmit(), which is sk_buff pointer became > NULL. > > This seems some async skb freeing is in progress? > > Regards, > Jianyu Zhan > -- 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/