From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757566Ab2JEV7f (ORCPT ); Fri, 5 Oct 2012 17:59:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50975 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751743Ab2JEV7d (ORCPT ); Fri, 5 Oct 2012 17:59:33 -0400 Date: Fri, 5 Oct 2012 17:59:29 -0400 From: Dave Jones To: linux-kernel@vger.kernel.org Cc: aris@redhat.com Subject: suspicious RCU usage in cgroup Message-ID: <20121005215926.GA2406@redhat.com> Mail-Followup-To: Dave Jones , linux-kernel@vger.kernel.org, aris@redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On boot in Linus' current tree.. =============================== [ INFO: suspicious RCU usage. ] 3.6.0+ #22 Not tainted ------------------------------- include/linux/cgroup.h:566 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 2 locks on stack by kdevtmpfs/59: #0: blocked: (sb_writers){.+.+.+}, instance: ffff88014595a9a0, at: [] mnt_want_write+0x24/0x50 #1: held: (&sb->s_type->i_mutex_key#3/1){+.+.+.}, instance: ffff880145b1f5c8, at: [] kern_path_create+0x84/0x170 stack backtrace: Pid: 59, comm: kdevtmpfs Not tainted 3.6.0+ #22 Call Trace: [] lockdep_rcu_suspicious+0xe2/0x130 [] devcgroup_inode_mknod+0x19d/0x240 [] ? security_capable+0x18/0x20 [] ? ns_capable+0x44/0x80 [] vfs_mknod+0x7e/0x140 [] handle_create.isra.2+0x77/0x210 [] ? lock_release_holdtime.part.26+0xcc/0x140 [] ? get_parent_ip+0x11/0x50 [] ? sub_preempt_count+0x79/0xd0 [] devtmpfsd+0x147/0x170 [] ? handle_create.isra.2+0x210/0x210 [] kthread+0xed/0x100 [] ? sub_preempt_count+0x79/0xd0 [] kernel_thread_helper+0x4/0x10 [] ? finish_task_switch+0x7c/0x120 [] ? _raw_spin_unlock_irq+0x4b/0x80 [] ? retint_restore_args+0x13/0x13 [] ? kthread_create_on_node+0x160/0x160 [] ? gs_change+0x13/0x13