From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937181AbdEWRwv (ORCPT ); Tue, 23 May 2017 13:52:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39210 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933016AbdEWRwu (ORCPT ); Tue, 23 May 2017 13:52:50 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 5D4FB6AF4 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jpoimboe@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 5D4FB6AF4 Date: Tue, 23 May 2017 12:52:47 -0500 From: Josh Poimboeuf To: Petr Mladek Cc: Jessica Yu , Jiri Kosina , Miroslav Benes , Steven Rostedt , "Paul E. McKenney" , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] livepatch/rcu: Fix stacking of patches when RCU infrastructure is patched Message-ID: <20170523175247.akvppkoi55foh5my@treble> References: <1495554451-13481-1-git-send-email-pmladek@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1495554451-13481-1-git-send-email-pmladek@suse.com> User-Agent: Mutt/1.6.0.1 (2016-04-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 23 May 2017 17:52:49 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 23, 2017 at 05:47:31PM +0200, Petr Mladek wrote: > diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c > index f8269036bf0b..08acba30ecec 100644 > --- a/kernel/livepatch/patch.c > +++ b/kernel/livepatch/patch.c > @@ -59,7 +59,11 @@ static void notrace klp_ftrace_handler(unsigned long ip, > > ops = container_of(fops, struct klp_ops, fops); > > - rcu_read_lock(); > + /* > + * A variant of synchronize_sched() is used to allow pathing functions > + * where RCU is not wathing, see klp_synchronize_transition(). > + */ > + preempt_disable_notrace(); s/pathing/patching/ s/wathing/watching/ (and same for the duplicated version of the comment below.) Otherwise the patch looks promising, though I'll need to stare at it for a while... -- Josh