From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E42FFC07E9A for ; Mon, 5 Jul 2021 07:53:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C25A1613FC for ; Mon, 5 Jul 2021 07:53:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230132AbhGEH4S (ORCPT ); Mon, 5 Jul 2021 03:56:18 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:59068 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230025AbhGEH4N (ORCPT ); Mon, 5 Jul 2021 03:56:13 -0400 Date: Mon, 05 Jul 2021 07:53:35 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1625471615; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=F56OkhqMYKLV2rUyCNDsST0BwOUxOHhe8mnEjAiQtUs=; b=BLCa7fRWxRtHtyFB3euhWC1SU/Got2w5kt187gGtIExSZtdfiOeQzxAo3kvIvT0Gb52NxM VW9xb+U/hfamdvg0lS/LBmF5R3dTo8a3zq1kF6QSWnBUP+YwmYeE9x5PsPwI3JHh9020Jn pqgp6AR17usvUK1y6hOVlX+fQsZi5seUcZWu7/CwmJC1mVzfSKROWW5/ybjYPBYjjrLXnp yVWkFvgP3ppmvVTifFkayfCUJcvp7gD4WlWLSZqAamdIWYzZo4OIUb/jAnkui8WAOQnUTe wkLkQ5bXlaJhvdFVFb/cCcwWskImE12cUfvvTgP9x0i/DNM+zsORMzqJJPaffA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1625471615; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=F56OkhqMYKLV2rUyCNDsST0BwOUxOHhe8mnEjAiQtUs=; b=Ejl1b9PLGPL+qU6eONa3Ndb0EsFww97MmHJSxqb4CGFVLSJRK2/jha9srFDLTz4gOTSxLf Q30Vb2K8PG7x2xAA== From: "tip-bot2 for Xiongwei Song" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/urgent] locking/lockdep: Fix meaningless usages output of lock classes Cc: Xiongwei Song , "Peter Zijlstra (Intel)" , Waiman Long , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210629135916.308210-1-sxwjean@me.com> References: <20210629135916.308210-1-sxwjean@me.com> MIME-Version: 1.0 Message-ID: <162547161509.395.12111477332753183993.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/urgent branch of tip: Commit-ID: a23fb0cfa911423327e5a2089d33ab6cddc6a6aa Gitweb: https://git.kernel.org/tip/a23fb0cfa911423327e5a2089d33ab6cddc6a6aa Author: Xiongwei Song AuthorDate: Tue, 29 Jun 2021 21:59:16 +08:00 Committer: Peter Zijlstra CommitterDate: Fri, 02 Jul 2021 15:58:26 +02:00 locking/lockdep: Fix meaningless usages output of lock classes When enabling CONFIG_LOCK_STAT, then CONFIG_LOCKDEP is forcedly enabled. We can get output from /proc/lockdep, which currently includes usages of lock classes. But the usages are meaningless, see the output below: / # cat /proc/lockdep all lock classes: ffffffff9af63350 ....: cgroup_mutex ffffffff9af54eb8 ....: (console_sem).lock ffffffff9af54e60 ....: console_lock ffffffff9ae74c38 ....: console_owner_lock ffffffff9ae74c80 ....: console_owner ffffffff9ae66e60 ....: cpu_hotplug_lock Only one usage context for each lock, this is because each usage is only changed in mark_lock() that is in CONFIG_PROVE_LOCKING defined section, however in the test situation, it's not. The fix is to move the usages reading and seq_print from CONFIG_PROVE_LOCKING undefined setcion to its defined section. Also, locks_after list of lock_class is empty when CONFIG_PROVE_LOCKING undefined, so do the same thing as what have done for usages of lock classes. With this patch with CONFIG_PROVE_LOCKING undefined, we can get the results below: / # cat /proc/lockdep all lock classes: ffffffff85163290: cgroup_mutex ffffffff85154dd8: (console_sem).lock ffffffff85154d80: console_lock ffffffff85074b58: console_owner_lock ffffffff85074ba0: console_owner ffffffff85066d60: cpu_hotplug_lock a class key and the relevant class name each line. Signed-off-by: Xiongwei Song Signed-off-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Link: https://lore.kernel.org/r/20210629135916.308210-1-sxwjean@me.com --- kernel/locking/lockdep_proc.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 8069783..b8d9a05 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -70,26 +70,28 @@ static int l_show(struct seq_file *m, void *v) #ifdef CONFIG_DEBUG_LOCKDEP seq_printf(m, " OPS:%8ld", debug_class_ops_read(class)); #endif -#ifdef CONFIG_PROVE_LOCKING - seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class)); - seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class)); -#endif + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { + seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class)); + seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class)); - get_usage_chars(class, usage); - seq_printf(m, " %s", usage); + get_usage_chars(class, usage); + seq_printf(m, " %s", usage); + } seq_printf(m, ": "); print_name(m, class); seq_puts(m, "\n"); - list_for_each_entry(entry, &class->locks_after, entry) { - if (entry->distance == 1) { - seq_printf(m, " -> [%p] ", entry->class->key); - print_name(m, entry->class); - seq_puts(m, "\n"); + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { + list_for_each_entry(entry, &class->locks_after, entry) { + if (entry->distance == 1) { + seq_printf(m, " -> [%p] ", entry->class->key); + print_name(m, entry->class); + seq_puts(m, "\n"); + } } + seq_puts(m, "\n"); } - seq_puts(m, "\n"); return 0; }