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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 D957EC282CD for ; Mon, 28 Jan 2019 16:19:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA1C42173C for ; Mon, 28 Jan 2019 16:19:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548692381; bh=TTuK3QqcQkUFe9aAzqj+Vy3POPJDwDhPtLu3943eglA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OkpDooleVhXiC/ew05nXs49SDElTNMOqiJkK0L1FkF2P6B/OZpyQhukrLqsPVcXvP Fz71UtFSJVoxfbeKznkqhI0UT9CO+YgSmbBbgb5SGw7pPfKWZ9Fx+kEDGvXGI0Vdpa huWhTv07yzBpDp8vwRHW8aEmR78hFRc2Rl3RIOss= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388243AbfA1QTk (ORCPT ); Mon, 28 Jan 2019 11:19:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:54432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388631AbfA1QTh (ORCPT ); Mon, 28 Jan 2019 11:19:37 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7B53D2171F; Mon, 28 Jan 2019 16:19:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548692376; bh=TTuK3QqcQkUFe9aAzqj+Vy3POPJDwDhPtLu3943eglA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G8GxDscAa4l//CSbyUumm3hNE0bZHEnSYuqgx6f3D+ezUIRL/OB8+MkY3xd9/6bKU GbuDfhXcljdiytVlZh1pBSSroxE5AohePH3uf1svaVjnq9mdqpjXV0NT1WnbKw5Bd9 hEHSgfgahgN86qzN2bgXStC1DyrYmXJgUNnhgFio= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Liu, Chuansheng" , Tetsuo Handa , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH AUTOSEL 4.14 167/170] kernel/hung_task.c: force console verbose before panic Date: Mon, 28 Jan 2019 11:11:57 -0500 Message-Id: <20190128161200.55107-167-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190128161200.55107-1-sashal@kernel.org> References: <20190128161200.55107-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Liu, Chuansheng" [ Upstream commit 168e06f7937d96c7222037d8a05565e8a6eb00fe ] Based on commit 401c636a0eeb ("kernel/hung_task.c: show all hung tasks before panic"), we could get the call stack of hung task. However, if the console loglevel is not high, we still can not see the useful panic information in practice, and in most cases users don't set console loglevel to high level. This patch is to force console verbose before system panic, so that the real useful information can be seen in the console, instead of being like the following, which doesn't have hung task information. INFO: task init:1 blocked for more than 120 seconds. Tainted: G U W 4.19.0-quilt-2e5dc0ac-g51b6c21d76cc #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Kernel panic - not syncing: hung_task: blocked tasks CPU: 2 PID: 479 Comm: khungtaskd Tainted: G U W 4.19.0-quilt-2e5dc0ac-g51b6c21d76cc #1 Call Trace: dump_stack+0x4f/0x65 panic+0xde/0x231 watchdog+0x290/0x410 kthread+0x12c/0x150 ret_from_fork+0x35/0x40 reboot: panic mode set: p,w Kernel Offset: 0x34000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A6015B675@SHSMSX101.ccr.corp.intel.com Signed-off-by: Chuansheng Liu Reviewed-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Cc: Tetsuo Handa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- kernel/hung_task.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 0cec1241e26f..f9aaf4994062 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -103,8 +103,11 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) trace_sched_process_hang(t); - if (!sysctl_hung_task_warnings && !sysctl_hung_task_panic) - return; + if (sysctl_hung_task_panic) { + console_verbose(); + hung_task_show_lock = true; + hung_task_call_panic = true; + } /* * Ok, the task did not get scheduled for more than 2 minutes, @@ -126,11 +129,6 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) } touch_nmi_watchdog(); - - if (sysctl_hung_task_panic) { - hung_task_show_lock = true; - hung_task_call_panic = true; - } } /* -- 2.19.1