From patchwork Wed Jun 3 18:20:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yannick Cote X-Patchwork-Id: 11586127 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 517CA913 for ; Wed, 3 Jun 2020 18:21:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35C252074B for ; Wed, 3 Jun 2020 18:21:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eSj3sSut" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726134AbgFCSVm (ORCPT ); Wed, 3 Jun 2020 14:21:42 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:28364 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726087AbgFCSVm (ORCPT ); Wed, 3 Jun 2020 14:21:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591208500; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bAac06P3giR5I4Nc3J9vi1Ip90+x7WJLQsxk772I3oE=; b=eSj3sSutCTgPIZrPN+bvJkTApoqEaTuNKjMBPwh3eXuc8hx84qJ7OetzMWfcIpZvnlduST 1CsXjblQrnCoHWsMqDu1GVey+9lqmvij5pr5WXpxOMbhNrEgXenu+Nvfjx5YiOBecT5HOU EWNx3Z+6Dy2oPcT+J30mEb3DWsVtraw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-67-0WpOuRSGP_6tlyvkYlfIIg-1; Wed, 03 Jun 2020 14:21:35 -0400 X-MC-Unique: 0WpOuRSGP_6tlyvkYlfIIg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9D1A71800D42; Wed, 3 Jun 2020 18:21:34 +0000 (UTC) Received: from dm.redhat.com (unknown [10.10.67.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id 938FD5D9CD; Wed, 3 Jun 2020 18:21:33 +0000 (UTC) From: Yannick Cote To: live-patching@vger.kernel.org Cc: linux-kselftest@vger.kernel.org, joe.lawrence@redhat.com, linux-kernel@vger.kernel.org, pmladek@suse.com, mbenes@suse.cz, kamalesh@linux.vnet.ibm.com Subject: [PATCH v2 1/4] selftests/livepatch: simplify test-klp-callbacks busy target tests Date: Wed, 3 Jun 2020 14:20:55 -0400 Message-Id: <20200603182058.109470-2-ycote@redhat.com> In-Reply-To: <20200603182058.109470-1-ycote@redhat.com> References: <20200603182058.109470-1-ycote@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Joe Lawrence The test-klp-callbacks script includes a few tests which rely on kernel task timings that may not always execute as expected under system load. These may generate out of sequence kernel log messages that result in test failure. Instead of using sleep timing windows to orchestrate these tests, add a block_transition module parameter to communicate the test purpose and utilize flush_queue() to serialize the test module's task output. Suggested-by: Petr Mladek Signed-off-by: Joe Lawrence Reviewed-by: Petr Mladek Acked-by: Miroslav Benes --- lib/livepatch/test_klp_callbacks_busy.c | 37 ++++++++++++++----- .../selftests/livepatch/test-callbacks.sh | 29 +++++++-------- 2 files changed, 42 insertions(+), 24 deletions(-) diff --git a/lib/livepatch/test_klp_callbacks_busy.c b/lib/livepatch/test_klp_callbacks_busy.c index 40beddf8a0e2..7ac845f65be5 100644 --- a/lib/livepatch/test_klp_callbacks_busy.c +++ b/lib/livepatch/test_klp_callbacks_busy.c @@ -5,34 +5,53 @@ #include #include +#include #include #include -static int sleep_secs; -module_param(sleep_secs, int, 0644); -MODULE_PARM_DESC(sleep_secs, "sleep_secs (default=0)"); +/* load/run-time control from sysfs writer */ +static bool block_transition; +module_param(block_transition, bool, 0644); +MODULE_PARM_DESC(block_transition, "block_transition (default=false)"); static void busymod_work_func(struct work_struct *work); -static DECLARE_DELAYED_WORK(work, busymod_work_func); +static DECLARE_WORK(work, busymod_work_func); static void busymod_work_func(struct work_struct *work) { - pr_info("%s, sleeping %d seconds ...\n", __func__, sleep_secs); - msleep(sleep_secs * 1000); + pr_info("%s enter\n", __func__); + + while (READ_ONCE(block_transition)) { + /* + * Busy-wait until the sysfs writer has acknowledged a + * blocked transition and clears the flag. + */ + msleep(20); + } + pr_info("%s exit\n", __func__); } static int test_klp_callbacks_busy_init(void) { pr_info("%s\n", __func__); - schedule_delayed_work(&work, - msecs_to_jiffies(1000 * 0)); + schedule_work(&work); + + if (!block_transition) { + /* + * Serialize output: print all messages from the work + * function before returning from init(). + */ + flush_work(&work); + } + return 0; } static void test_klp_callbacks_busy_exit(void) { - cancel_delayed_work_sync(&work); + WRITE_ONCE(block_transition, false); + flush_work(&work); pr_info("%s\n", __func__); } diff --git a/tools/testing/selftests/livepatch/test-callbacks.sh b/tools/testing/selftests/livepatch/test-callbacks.sh index a35289b13c9c..32b57ba07f4f 100755 --- a/tools/testing/selftests/livepatch/test-callbacks.sh +++ b/tools/testing/selftests/livepatch/test-callbacks.sh @@ -356,9 +356,7 @@ livepatch: '$MOD_LIVEPATCH': unpatching complete echo -n "TEST: multiple target modules ... " dmesg -C -load_mod $MOD_TARGET_BUSY sleep_secs=0 -# give $MOD_TARGET_BUSY::busymod_work_func() a chance to run -sleep 5 +load_mod $MOD_TARGET_BUSY block_transition=N load_lp $MOD_LIVEPATCH load_mod $MOD_TARGET unload_mod $MOD_TARGET @@ -366,9 +364,9 @@ disable_lp $MOD_LIVEPATCH unload_lp $MOD_LIVEPATCH unload_mod $MOD_TARGET_BUSY -check_result "% modprobe $MOD_TARGET_BUSY sleep_secs=0 +check_result "% modprobe $MOD_TARGET_BUSY block_transition=N $MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_init -$MOD_TARGET_BUSY: busymod_work_func, sleeping 0 seconds ... +$MOD_TARGET_BUSY: busymod_work_func enter $MOD_TARGET_BUSY: busymod_work_func exit % modprobe $MOD_LIVEPATCH livepatch: enabling patch '$MOD_LIVEPATCH' @@ -404,11 +402,10 @@ livepatch: '$MOD_LIVEPATCH': unpatching complete $MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_exit" - # TEST: busy target module # # A similar test as the previous one, but force the "busy" kernel module -# to do longer work. +# to block the livepatch transition. # # The livepatching core will refuse to patch a task that is currently # executing a to-be-patched function -- the consistency model stalls the @@ -417,8 +414,7 @@ $MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_exit" # function for a long time. Meanwhile, load and unload other target # kernel modules while the livepatch transition is in progress. # -# - Load the "busy" kernel module, this time make it do 10 seconds worth -# of work. +# - Load the "busy" kernel module, this time make its work function loop # # - Meanwhile, the livepatch is loaded. Notice that the patch # transition does not complete as the targeted "busy" module is @@ -438,20 +434,23 @@ $MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_exit" echo -n "TEST: busy target module ... " dmesg -C -load_mod $MOD_TARGET_BUSY sleep_secs=10 +load_mod $MOD_TARGET_BUSY block_transition=Y load_lp_nowait $MOD_LIVEPATCH -# Don't wait for transition, load $MOD_TARGET while the transition -# is still stalled in $MOD_TARGET_BUSY::busymod_work_func() -sleep 5 + +# Wait until the livepatch reports in-transition state, i.e. that it's +# stalled on $MOD_TARGET_BUSY::busymod_work_func() +loop_until 'grep -q '^1$' /sys/kernel/livepatch/$MOD_LIVEPATCH/transition' || + die "failed to stall transition" + load_mod $MOD_TARGET unload_mod $MOD_TARGET disable_lp $MOD_LIVEPATCH unload_lp $MOD_LIVEPATCH unload_mod $MOD_TARGET_BUSY -check_result "% modprobe $MOD_TARGET_BUSY sleep_secs=10 +check_result "% modprobe $MOD_TARGET_BUSY block_transition=Y $MOD_TARGET_BUSY: ${MOD_TARGET_BUSY}_init -$MOD_TARGET_BUSY: busymod_work_func, sleeping 10 seconds ... +$MOD_TARGET_BUSY: busymod_work_func enter % modprobe $MOD_LIVEPATCH livepatch: enabling patch '$MOD_LIVEPATCH' livepatch: '$MOD_LIVEPATCH': initializing patching transition