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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 49764C33CB1 for ; Mon, 27 Jan 2020 14:03:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DB4D214D8 for ; Mon, 27 Jan 2020 14:03:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="XdBfqwKM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729021AbgA0ODt (ORCPT ); Mon, 27 Jan 2020 09:03:49 -0500 Received: from forwardcorp1j.mail.yandex.net ([5.45.199.163]:52470 "EHLO forwardcorp1j.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727161AbgA0ODs (ORCPT ); Mon, 27 Jan 2020 09:03:48 -0500 Received: from mxbackcorp1j.mail.yandex.net (mxbackcorp1j.mail.yandex.net [IPv6:2a02:6b8:0:1619::162]) by forwardcorp1j.mail.yandex.net (Yandex) with ESMTP id B8B912E0EE4; Mon, 27 Jan 2020 17:03:45 +0300 (MSK) Received: from sas2-3e4aeb094591.qloud-c.yandex.net (sas2-3e4aeb094591.qloud-c.yandex.net [2a02:6b8:c08:7192:0:640:3e4a:eb09]) by mxbackcorp1j.mail.yandex.net (mxbackcorp/Yandex) with ESMTP id GvPU8Sj2TX-3iamNSWn; Mon, 27 Jan 2020 17:03:45 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1580133825; bh=rWO+pqoXgW5yqvcPcqbiWtbWQJgJM6IEA14o0BsyOF4=; h=In-Reply-To:Message-ID:References:Date:To:From:Subject:Cc; b=XdBfqwKMRfeDxiZrlppDiBKnPSzqK2bFtBeI2vu1LaYjpmxa3QOCxK7cJ1EKsSCLr rVm2V7yBh0sNw31ajOFW2EI2SLivUHTz+1WPXGgOw6tTzQjWSUS3TRRrnQdz2E3d7Y WcZXoXT2Tsjy3ydAEkYF/o7l1+pF9t9H39a3Jt4o= Authentication-Results: mxbackcorp1j.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-red.dhcp.yndx.net (dynamic-red.dhcp.yndx.net [2a02:6b8:0:40c:8448:fbcc:1dac:c863]) by sas2-3e4aeb094591.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id x7h0qwLzMk-3iYeQPfD; Mon, 27 Jan 2020 17:03:44 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Subject: [PATCH v2 2/3] kernel: set taint flag 'L' at any kind of lockup From: Konstantin Khlebnikov To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: Sasha Levin , Kees Cook , "Paul E. McKenney" , Greg Kroah-Hartman , rcu@vger.kernel.org, Tejun Heo , Andrew Morton , Linus Torvalds , Thomas Gleixner Date: Mon, 27 Jan 2020 17:03:44 +0300 Message-ID: <158013382455.1528.13267155216574129417.stgit@buzz> In-Reply-To: <158013382063.1528.13355932625960922673.stgit@buzz> References: <158013382063.1528.13355932625960922673.stgit@buzz> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Any lockup or stall detector notifies about unexpected lack of progress. It's better to know about these splats at investigating further problems. This patch set TAINT_LOCKUP at: - softlockup (CONFIG_SOFTLOCKUP_DETECTOR) - hardlockup (CONFIG_HARDLOCKUP_DETECTOR) - RCU stall (Documentation/RCU/stallwarn.txt) - hung task (CONFIG_DETECT_HUNG_TASK) - stuck in workqueues (CONFIG_WQ_WATCHDOG) Signed-off-by: Konstantin Khlebnikov Acked-by: Paul E. McKenney (RCU part) Link: https://lore.kernel.org/lkml/157503370645.8187.6335564487789994134.stgit@buzz/ (v1) --- Documentation/admin-guide/tainted-kernels.rst | 4 ++++ kernel/hung_task.c | 2 ++ kernel/rcu/tree_stall.h | 1 + kernel/watchdog_hld.c | 1 + kernel/workqueue.c | 1 + 5 files changed, 9 insertions(+) diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index 55d45211cb41..13249240283c 100644 --- a/Documentation/admin-guide/tainted-kernels.rst +++ b/Documentation/admin-guide/tainted-kernels.rst @@ -153,6 +153,10 @@ More detailed explanation for tainting module signature. 14) ``L`` if a lockup has previously occurred on the system. + - soft/hardlockup, see Documentation/admin-guide/lockup-watchdogs.rst + - RCU stall, see Documentation/RCU/stallwarn.txt + - hung task detected, see CONFIG_DETECT_HUNG_TASK + - kernel workqueue lockup, see CONFIG_WQ_WATCHDOG 15) ``K`` if the kernel has been live patched. diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 14a625c16cb3..521eb2fbf5fc 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -139,6 +139,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) hung_task_show_lock = true; } + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); + touch_nmi_watchdog(); } diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index c0b8c458d8a6..181495efff80 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -74,6 +74,7 @@ early_initcall(check_cpu_stall_init); /* If so specified via sysctl, panic, yielding cleaner stall-warning output. */ static void panic_on_rcu_stall(void) { + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); if (sysctl_panic_on_rcu_stall) panic("RCU Stall\n"); } diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c index 247bf0b1582c..f77256f47422 100644 --- a/kernel/watchdog_hld.c +++ b/kernel/watchdog_hld.c @@ -152,6 +152,7 @@ static void watchdog_overflow_callback(struct perf_event *event, !test_and_set_bit(0, &hardlockup_allcpu_dumped)) trigger_allbutself_cpu_backtrace(); + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); if (hardlockup_panic) nmi_panic(regs, "Hard LOCKUP"); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index cfc923558e04..1b3c81d87a0d 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5774,6 +5774,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused) pr_cont_pool_info(pool); pr_cont(" stuck for %us!\n", jiffies_to_msecs(jiffies - pool_ts) / 1000); + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); } }