Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751834AbbFBU6w (ORCPT ); Tue, 2 Jun 2015 16:58:52 -0400 Received: from cantor2.suse.de ([195.135.220.15]:58496 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751398AbbFBU6o (ORCPT ); Tue, 2 Jun 2015 16:58:44 -0400 Date: Tue, 2 Jun 2015 22:58:42 +0200 (CEST) From: Jiri Kosina To: Josh Poimboeuf , Miroslav Benes cc: sjenning@redhat.com, Vojtech Pavlik , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, pmladek@suse.cz Subject: Re: [PATCH] livepatch: add module locking around kallsyms calls In-Reply-To: <20150602150915.GB24773@treble.redhat.com> Message-ID: References: <1433173717-20885-1-git-send-email-mbenes@suse.cz> <20150602150915.GB24773@treble.redhat.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1452 Lines: 40 On Tue, 2 Jun 2015, Josh Poimboeuf wrote: > On Mon, Jun 01, 2015 at 05:48:37PM +0200, Miroslav Benes wrote: > > The list of loaded modules is walked through in > > module_kallsyms_on_each_symbol (called by kallsyms_on_each_symbol). The > > module_mutex lock should be acquired to prevent potential corruptions > > in the list. > > > > This was uncovered with new lockdep asserts in module code introduced by > > the commit 0be964be0d45 ("module: Sanitize RCU usage and locking") in > > recent next- trees. > > > > Signed-off-by: Miroslav Benes > > Thanks! > > Should we add a comment to kallsyms_on_each_symbol() so that others > don't make this mistake? Yeah, the locking rules in module loader are not really crystal clear (not even after Peterz's revamp in -next), so some comment / lockdep assertion might be helpful. But let's keep that separate from this functional fix in klp. > Acked-by: Josh Poimboeuf I have now queued this in for-4.1/upstream-fixes, but I don't think I'll rush this in for -final now, therefore I added Cc: stable as well. If there is -rc7, I'll push it to Linus for -final early next week. Thanks, -- Jiri Kosina SUSE Labs -- 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/