From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756359AbYDUJOf (ORCPT ); Mon, 21 Apr 2008 05:14:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754861AbYDUJO0 (ORCPT ); Mon, 21 Apr 2008 05:14:26 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:36479 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754621AbYDUJOY (ORCPT ); Mon, 21 Apr 2008 05:14:24 -0400 Subject: Re: Possible circular locking dependency while running valgrind on an executable over CIFS From: Peter Zijlstra To: Brandon Ehle Cc: linux-kernel@vger.kernel.org, Steve French , Ingo Molnar In-Reply-To: <3c5a513f0804202004y35820ddfse9195f883428a7db@mail.gmail.com> References: <3c5a513f0804202004y35820ddfse9195f883428a7db@mail.gmail.com> Content-Type: text/plain Date: Mon, 21 Apr 2008 11:14:22 +0200 Message-Id: <1208769262.7115.164.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2008-04-20 at 20:04 -0700, Brandon Ehle wrote: > While running valgrind on various executables located on a CIFS share, > I eventually got the message below. The machine in question is > running 2.6.25 with a few of the debug options enabled, including lock > debugging. Any idea if this is indicative of a real problem or just a > false positive? Looks like a simple AB-BA deadlock to me. I admint being a bit ignorant about CIFS (nor really minding that) however it looks like you need to delay or decouple the actual sending of the read request from the .readpages() implementation. Steve? > ======================================================= > [ INFO: possible circular locking dependency detected ] > 2.6.25 #29 > ------------------------------------------------------- > valgrind.bin/23200 is trying to acquire lock: > (sk_lock-AF_INET){--..}, at: [] tcp_sendmsg+0x17/0xb00 > > but task is already holding lock: > (&mm->mmap_sem){----}, at: [] do_page_fault+0x16d/0x8e0 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #1 (&mm->mmap_sem){----}: > [] __lock_acquire+0xfa9/0xfdb > [] lock_acquire+0x8a/0xbd > [] down_read+0x3d/0x85 > [] do_page_fault+0x185/0x8e0 > [] error_code+0x72/0x78 > [] memcpy_toiovec+0x43/0x5a > [] skb_copy_datagram_iovec+0x47/0x1d7 > [] tcp_recvmsg+0xb3d/0xcc8 > [] sock_common_recvmsg+0x3d/0x53 > [] sock_recvmsg+0x10d/0x12a > [] sys_recvfrom+0x7c/0xc7 > [] sys_recv+0x36/0x38 > [] sys_socketcall+0x163/0x25b > [] sysenter_past_esp+0x6d/0xc5 > [] 0xffffffff > > -> #0 (sk_lock-AF_INET){--..}: > [] __lock_acquire+0xba1/0xfdb > [] lock_acquire+0x8a/0xbd > [] lock_sock_nested+0xb5/0xc2 > [] tcp_sendmsg+0x17/0xb00 > [] sock_sendmsg+0xf9/0x116 > [] kernel_sendmsg+0x28/0x37 > [] SendReceive2+0x197/0x69b > [] CIFSSMBRead+0x110/0x2a0 > [] cifs_readpages+0x18c/0x5c7 > [] __do_page_cache_readahead+0x161/0x1e1 > [] do_page_cache_readahead+0x45/0x59 > [] filemap_fault+0x30f/0x467 > [] __do_fault+0x56/0x43a > [] handle_mm_fault+0x150/0x873 > [] do_page_fault+0x39d/0x8e0 > [] error_code+0x72/0x78 > [] 0xffffffff > > other info that might help us debug this: > > 1 lock held by valgrind.bin/23200: > #0: (&mm->mmap_sem){----}, at: [] do_page_fault+0x16d/0x8e0 > > stack backtrace: > Pid: 23200, comm: valgrind.bin Not tainted 2.6.25 #29 > [] print_circular_bug_tail+0x68/0x6a > [] __lock_acquire+0xba1/0xfdb > [] ? restore_nocheck+0x12/0x15 > [] lock_acquire+0x8a/0xbd > [] ? tcp_sendmsg+0x17/0xb00 > [] lock_sock_nested+0xb5/0xc2 > [] ? tcp_sendmsg+0x17/0xb00 > [] tcp_sendmsg+0x17/0xb00 > [] ? get_lock_stats+0x1b/0x3e > [] ? getnstimeofday+0x34/0xde > [] ? lapic_next_event+0x15/0x1e > [] sock_sendmsg+0xf9/0x116 > [] ? mempool_alloc_slab+0xe/0x10 > [] ? autoremove_wake_function+0x0/0x3a > [] ? _spin_unlock+0x27/0x42 > [] ? allocate_mid+0xec/0x149 > [] kernel_sendmsg+0x28/0x37 > [] SendReceive2+0x197/0x69b > [] CIFSSMBRead+0x110/0x2a0 > [] cifs_readpages+0x18c/0x5c7 > [] ? __alloc_pages+0x6d/0x3c7 > [] ? mark_held_locks+0x4d/0x84 > [] ? __rcu_read_unlock+0x81/0xa4 > [] ? cifs_readpages+0x0/0x5c7 > [] __do_page_cache_readahead+0x161/0x1e1 > [] do_page_cache_readahead+0x45/0x59 > [] filemap_fault+0x30f/0x467 > [] __do_fault+0x56/0x43a > [] handle_mm_fault+0x150/0x873 > [] ? native_sched_clock+0xa6/0xea > [] ? do_page_fault+0x16d/0x8e0 > [] ? down_read_trylock+0x51/0x59 > [] do_page_fault+0x39d/0x8e0 > [] ? __lock_acquire+0x2d1/0xfdb > [] ? vma_link+0xbc/0xd4 > [] ? __filemap_fdatawrite_range+0x61/0x6d > [] ? filemap_fdatawrite+0x26/0x28 > [] ? cifs_flush+0x1c/0x5c > [] ? sysenter_past_esp+0xb6/0xc5 > [] ? trace_hardirqs_on+0x10a/0x15a > [] ? do_page_fault+0x0/0x8e0 > [] error_code+0x72/0x78 > =======================