From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932902AbaE2RaY (ORCPT ); Thu, 29 May 2014 13:30:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22402 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932372AbaE2RaW (ORCPT ); Thu, 29 May 2014 13:30:22 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <27993.1401360881@warthog.procyon.org.uk> References: <27993.1401360881@warthog.procyon.org.uk> <1400838223-30844-1-git-send-email-miklos@szeredi.hu> To: Miklos Szeredi Cc: dhowells@redhat.com, viro@ZenIV.linux.org.uk, torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, hch@infradead.org, akpm@linux-foundation.org, apw@canonical.com, nbd@openwrt.org, neilb@suse.de, jordipujolp@gmail.com, ezk@fsl.cs.sunysb.edu, sedat.dilek@gmail.com, hooanon05@yahoo.co.jp, mszeredi@suse.cz Subject: Re: Kernel errors with overlay filesystem v22 Date: Thu, 29 May 2014 18:29:36 +0100 Message-ID: <29283.1401384576@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Here's another lockdep report for you. If you hard link a file, the attached occurs. ============================================= [ INFO: possible recursive locking detected ] 3.15.0-rc6-fsdevel+ #367 Tainted: G W --------------------------------------------- ln/2974 is trying to acquire lock: (&sb->s_type->i_mutex_key#9/2){+.+.+.}, at: [] generic_file_splice_write+0x88/0x154 but task is already holding lock: (&sb->s_type->i_mutex_key#9/2){+.+.+.}, at: [] lock_rename+0xd3/0xdc other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&sb->s_type->i_mutex_key#9/2); lock(&sb->s_type->i_mutex_key#9/2); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by ln/2974: #0: (sb_writers#15){.+.+.+}, at: [] mnt_want_write+0x1c/0x40 #1: (&sb->s_type->i_mutex_key#17/1){+.+.+.}, at: [] kern_path_create+0x76/0x121 #2: (&sb->s_type->i_mutex_key#17){+.+.+.}, at: [] vfs_link+0xf3/0x269 #3: (sb_writers#8){.+.+.+}, at: [] mnt_want_write+0x1c/0x40 #4: (&type->s_vfs_rename_key){+.+.+.}, at: [] lock_rename+0x3b/0xdc #5: (&sb->s_type->i_mutex_key#9/1){+.+.+.}, at: [] lock_rename+0xbe/0xdc #6: (&sb->s_type->i_mutex_key#9/2){+.+.+.}, at: [] lock_rename+0xd3/0xdc stack backtrace: CPU: 1 PID: 2974 Comm: ln Tainted: G W 3.15.0-rc6-fsdevel+ #367 Hardware name: /DG965RY, BIOS MQ96510J.86A.0816.2006.0716.2308 07/16/2006 0000000000000000 ffff8800383399c0 ffffffff8148b779 ffffffff81ffa7a0 ffff880038339a80 ffffffff81074b0e ffff880038339a00 ffff880038339a80 0000000000000000 0000000000000000 ffff880000000006 ffffffff00000000 Call Trace: [] dump_stack+0x4d/0x66 [] __lock_acquire+0x75a/0x1861 [] lock_acquire+0x9c/0x112 [] ? generic_file_splice_write+0x88/0x154 [] ? avc_has_perm+0x1d/0x13b [] mutex_lock_nested+0x60/0x2ff [] ? generic_file_splice_write+0x88/0x154 [] generic_file_splice_write+0x88/0x154 [] direct_splice_actor+0x31/0x33 [] splice_direct_to_actor+0xc6/0x188 [] ? opipe_prep.part.8+0x9e/0x9e [] do_splice_direct+0x73/0x9b [] ovl_copy_up_one+0x509/0x586 [] ovl_copy_up+0x9e/0xd3 [] ovl_link+0x1f/0x55 [] vfs_link+0x166/0x269 [] SyS_linkat+0x103/0x21d [] tracesys+0xdd/0xe2