Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932382Ab2HFSnr (ORCPT ); Mon, 6 Aug 2012 14:43:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:27903 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932273Ab2HFSnp (ORCPT ); Mon, 6 Aug 2012 14:43:45 -0400 Date: Mon, 6 Aug 2012 12:49:14 -0400 From: Dave Jones To: Linux Kernel Cc: eparis@redhat.com, paulmck@linux.vnet.ibm.com, paul@paul-moore.com, Andrew Morton , Linus Torvalds Subject: Re: Fix sel_netnode_insert suspicious rcu dereference. Message-ID: <20120806164914.GA25940@redhat.com> Mail-Followup-To: Dave Jones , Linux Kernel , eparis@redhat.com, paulmck@linux.vnet.ibm.com, paul@paul-moore.com, Andrew Morton , Linus Torvalds References: <20120605051238.GA30614@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120605051238.GA30614@redhat.com> 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 Content-Length: 2984 Lines: 73 On Tue, Jun 05, 2012 at 01:12:39AM -0400, Dave Jones wrote: > I reported this a year ago (https://lkml.org/lkml/2011/4/20/308). > It's still a problem apparently ... And another two months pass in silence. This is happening to other people too. https://bugzilla.redhat.com/show_bug.cgi?id=846037 Can someone please apply this patch, or at least point out what's wrong with it ? Dave > =============================== > [ INFO: suspicious RCU usage. ] > 3.5.0-rc1+ #63 Not tainted > ------------------------------- > security/selinux/netnode.c:178 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > rcu_scheduler_active = 1, debug_locks = 0 > 1 lock held by trinity-child1/8750: > #0: (sel_netnode_lock){+.....}, at: [] sel_netnode_sid+0x16a/0x3e0 > > stack backtrace: > Pid: 8750, comm: trinity-child1 Not tainted 3.5.0-rc1+ #63 > Call Trace: > [] lockdep_rcu_suspicious+0xfd/0x130 > [] sel_netnode_sid+0x3b1/0x3e0 > [] ? sel_netnode_find+0x1a0/0x1a0 > [] selinux_socket_bind+0xf6/0x2c0 > [] ? trace_hardirqs_off+0xd/0x10 > [] ? lock_release_holdtime.part.9+0x15/0x1a0 > [] ? lock_hrtimer_base+0x31/0x60 > [] security_socket_bind+0x16/0x20 > [] sys_bind+0x7a/0x100 > [] ? sysret_check+0x22/0x5d > [] ? trace_hardirqs_on_caller+0x10d/0x1a0 > [] ? trace_hardirqs_on_thunk+0x3a/0x3f > [] system_call_fastpath+0x16/0x1b > > This patch below does what Paul McKenney suggested in the previous thread. > > Signed-off-by: Dave Jones > > diff --git a/security/selinux/netnode.c b/security/selinux/netnode.c > index 28f911c..c5454c0 100644 > --- a/security/selinux/netnode.c > +++ b/security/selinux/netnode.c > @@ -174,7 +174,8 @@ static void sel_netnode_insert(struct sel_netnode *node) > if (sel_netnode_hash[idx].size == SEL_NETNODE_HASH_BKT_LIMIT) { > struct sel_netnode *tail; > tail = list_entry( > - rcu_dereference(sel_netnode_hash[idx].list.prev), > + rcu_dereference_protected(sel_netnode_hash[idx].list.prev, > + lockdep_is_held(&sel_netnode_lock)), > struct sel_netnode, list); > list_del_rcu(&tail->list); > kfree_rcu(tail, rcu); > -- > 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/ ---end quoted text--- -- 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/