From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751890AbeC0IWk (ORCPT ); Tue, 27 Mar 2018 04:22:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:33839 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751025AbeC0IWi (ORCPT ); Tue, 27 Mar 2018 04:22:38 -0400 Date: Tue, 27 Mar 2018 10:22:35 +0200 From: Petr Mladek To: Joe Lawrence Cc: Jiri Kosina , Josh Poimboeuf , Miroslav Benes , Jason Baron , Jessica Yu , Evgenii Shatokhin , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v10 00/10] livepatch: Atomic replace feature Message-ID: <20180327082235.eyujcqkcp4ccvkpk@pathway.suse.cz> References: <2f94c399-fe72-58f9-bd63-b08c46bb47b3@redhat.com> <1520881024-29386-1-git-send-email-joe.lawrence@redhat.com> <20180326105610.fzjfotkaljbuoa57@pathway.suse.cz> <6b1c58e4-9dc3-36bd-1fb6-e136605d0c66@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6b1c58e4-9dc3-36bd-1fb6-e136605d0c66@redhat.com> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2018-03-26 14:12:03, Joe Lawrence wrote: > On 03/26/2018 06:56 AM, Petr Mladek wrote: > > On Mon 2018-03-12 14:57:04, Joe Lawrence wrote: > >> diff --git a/tools/testing/selftests/livepatch/livepatch-test b/tools/testing/selftests/livepatch/livepatch-test > >> new file mode 100755 > >> index 000000000000..798317bf69f6 > >> --- /dev/null > >> +++ b/tools/testing/selftests/livepatch/livepatch-test > >> @@ -0,0 +1,658 @@ > >> +#!/bin/bash > >> +# SPDX-License-Identifier: GPL-2.0 > >> +# Copyright (C) 2018 Joe Lawrence > >> + > >> +MAX_RETRIES=30 > >> +RETRY_INTERVAL=2 # seconds > >> +BETWEEN_TESTS=20 # seconds > > > > These 20 seconds kept me in a tense (waiting for the final result) > > for a very long time ;-) Is there any particular reason for such > > a long delay? > > It certainly builds suspense :) > > > I wonder if we need a delay at all or if let's say 2 seconds might > > be enough. > > I removed the delays completely and the tests ran successfully. What > might be better than a between test delay would be some kind of > initial-condition verification, ie, make sure that the test starts/ends > with none of the livepatch test modules loaded. We could check is /sys/kernel/livepatch directory is empty. Also we could run modinfo on all modules printed by lsmod and check for the livepatch flag. > For the test cases which load multiple livepatches, is there an easy way > to determine the patch stack order from userspace? I think that would > be helpful when trying to remove all of them. I am not aware about any easy way. Only the following hacks come to my mind: One possibility would be to use the creation time of the directories under /sys/kernel/livepatch. Or I wonder if the output from lsmod is sorted by the order in which the modules were loaded. > >> +echo -n "TEST1 ... " > >> +dmesg -C > >> + > >> +load_mod $MOD_TARGET > >> +load_mod $MOD_LIVEPATCH > >> +wait_for_transition $MOD_LIVEPATCH > >> +disable_lp $MOD_LIVEPATCH > >> +unload_mod $MOD_LIVEPATCH > >> +unload_mod $MOD_TARGET > >> + > >> +check_result "% modprobe $MOD_TARGET > >> +$MOD_TARGET: livepatch_callbacks_mod_init > >> +% modprobe $MOD_LIVEPATCH > >> +livepatch: enabling patch '$MOD_LIVEPATCH' > >> +livepatch: '$MOD_LIVEPATCH': initializing patching transition > >> +$MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state > >> +$MOD_LIVEPATCH: pre_patch_callback: vmlinux > >> +livepatch: '$MOD_LIVEPATCH': starting patching transition > >> +livepatch: '$MOD_LIVEPATCH': completing patching transition > >> +$MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state > >> +$MOD_LIVEPATCH: post_patch_callback: vmlinux > >> +livepatch: '$MOD_LIVEPATCH': patching complete > >> +% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled > >> +livepatch: '$MOD_LIVEPATCH': initializing unpatching transition > >> +$MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state > >> +$MOD_LIVEPATCH: pre_unpatch_callback: vmlinux > >> +livepatch: '$MOD_LIVEPATCH': starting unpatching transition > >> +livepatch: '$MOD_LIVEPATCH': completing unpatching transition > >> +$MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state > >> +$MOD_LIVEPATCH: post_unpatch_callback: vmlinux > >> +livepatch: '$MOD_LIVEPATCH': unpatching complete > >> +% rmmod $MOD_LIVEPATCH > >> +% rmmod $MOD_TARGET > >> +$MOD_TARGET: livepatch_callbacks_mod_exit" > > > > I was a bit surprised when seeing this way of checking results. > > But on the other hand, it looks pretty effective, especially for > > the callbacks. And the 3rd look, any patched function might write > > something into the log when called. > > This was a quickly scripted version of what I was manually verifying > with the sample example livepatches. I don't know if it will scale, but > it was pretty easy to add tests this way. > > I wonder though if better dmesg filters will be required as the > livepatch core adds more debug msgs? Let's see. Most of the messages seem to be from the test modules itself, so it should not be that bad. > > I like it. Let's see how it works in the long term. But I am rather > > positive. > > > > Thanks a lot for working on it. > > Thanks for taking a look and running the tests. I'll make some of your > suggested changes and send it up for a proper review soon. Great. Best Regards, Petr