Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757376Ab3IMBsM (ORCPT ); Thu, 12 Sep 2013 21:48:12 -0400 Received: from mga14.intel.com ([143.182.124.37]:61267 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756187Ab3IMBsK (ORCPT ); Thu, 12 Sep 2013 21:48:10 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.90,894,1371106800"; d="scan'208";a="359816091" Subject: Re: [PATCH] Inet-hashtable: Change the range of sk->hash lock to avoid the race condition. From: Jun Chen To: Eric Dumazet Cc: edumazet@google.com, davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jun Chen In-Reply-To: <1378987204.24408.1.camel@edumazet-glaptop> References: <1379003549.12328.6.camel@chenjun-workstation> <1378987204.24408.1.camel@edumazet-glaptop> Content-Type: text/plain; charset="UTF-8" Date: Fri, 13 Sep 2013 05:47:23 -0400 Message-ID: <1379065643.3390.3.camel@chenjun-workstation> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2457 Lines: 56 On Thu, 2013-09-12 at 05:00 -0700, Eric Dumazet wrote: > On Thu, 2013-09-12 at 12:32 -0400, Jun Chen wrote: > > When try to add node to list in __inet_hash_nolisten function, first get the > > list and then to lock for using, but in extremeness case, others can del this > > node before locking it, then the node should be null.So this patch try to lock > > firstly and then get the list for using to avoid this race condition. > > I suspect another bug. This should not happen. > > Care to describe the problem you got ? > > Thanks > > Ok, I just got this call stack and no more info, pls help to look it. thanks! <1>[ 88.548263] BUG: unable to handle kernel NULL pointer dereference at 00000004 <1>[ 88.548490] IP: [] __inet_hash_nolisten+0xc1/0x140 <4>[ 88.548617] *pde = 00000000 <4>[ 88.549927] EIP is at __inet_hash_nolisten+0xc1/0x140 <4>[ 88.550008] EAX: 00000000 EBX: e08c0000 ECX: edf846e0 EDX: e08c0020 <4>[ 88.550055] ESI: c20213c0 EDI: edc12dc0 EBP: ce4bfdfc ESP: ce4bfde8 <4>[ 88.550137] DS: 007b ES: 007b FS: 00d8 GS: 003b SS: 0068 <4>[ 88.550184] CR0: 80050033 CR2: 00000004 CR3: 2b4ff000 CR4: 001007d0 <4>[ 88.550266] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 <4>[ 88.550346] DR6: ffff0ff0 DR7: 00000400 <0>[ 88.550392] Process WebViewCoreThre (pid: 2137, ti=ce4be000 task=eb193c80 task.ti=ce4be000) <0>[ 88.551746] Call Trace: <4>[ 88.551797] [] __inet_hash_connect+0x295/0x2d0 <4>[ 88.551883] [] inet_hash_connect+0x40/0x50 <4>[ 88.551932] [] ? inet_unhash+0x90/0x90 <4>[ 88.551981] [] ? __inet_lookup_listener+0x1b0/0x1b0 <4>[ 88.552067] [] tcp_v4_connect+0x247/0x4a0 <4>[ 88.552117] [] ? lock_sock_nested+0x3e/0x50 <4>[ 88.552205] [] inet_stream_connect+0xe2/0x290 <4>[ 88.552254] [] ? _copy_from_user+0x35/0x50 <4>[ 88.552342] [] sys_connect+0xb2/0xd0 <4>[ 88.552393] [] ? alloc_file+0x20/0xa0 <4>[ 88.552441] [] ? tcp_setsockopt+0x50/0x60 <4>[ 88.552525] [] ? fget_light+0x44/0xe0 <4>[ 88.552574] [] ? sock_common_setsockopt+0x27/0x40 <4>[ 88.552659] [] ? _copy_from_user+0x35/0x50 <4>[ 88.552708] [] sys_socketcall+0xab/0x2b0 <4>[ 88.552790] [] ? trace_hardirqs_on_thunk+0xc/0x10 <4>[ 88.552840] [] syscall_call+0x7/0xb <4>[ 88.552923] [] ? mutex_trylock+0x30/0x140 -- 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/