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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 D387DC282CE for ; Mon, 11 Feb 2019 14:34:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A3D9221B18 for ; Mon, 11 Feb 2019 14:34:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549895680; bh=HHr9pb+0odZX35N5oWawstpR2w7buBbmxeYyGWtJB9U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=quCpKG7/Nb3xAiVLGXI4PAMnx8QwlYaXE2rk4GWei6mwrArnHK2Ww8eYCsw9oVIpQ WEhZslenK4K8p8KpvmNYvE/yJEq5WbmBhiXBaXt/WEEY+65klCQoEdspHCsF6/JzP8 9uuAcY3iMD2ArqcferGPg6/tRF6KCigWpmo5DlGY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730890AbfBKOei (ORCPT ); Mon, 11 Feb 2019 09:34:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:42906 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730875AbfBKOef (ORCPT ); Mon, 11 Feb 2019 09:34:35 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0D4C02080F; Mon, 11 Feb 2019 14:34:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549895674; bh=HHr9pb+0odZX35N5oWawstpR2w7buBbmxeYyGWtJB9U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sVTBVBQUxBusg5JViBfrbQ3t51MbT90bpB1Tgx2bLFGMiYoymAXR4UUAlbS4Q6BAg zYiijR42j2nx2h3cAPZdKMlZ5/mtJ5nLQ2U/BxyR9AgDHZpKUcZZcMO+OkCoKqYLaB 3zzHQHwuLG4VnUGmfnJl+/xhwsJCIH0O4VCpOb6E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chuansheng Liu , Petr Mladek , Sergey Senozhatsky , Tetsuo Handa , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.20 285/352] kernel/hung_task.c: force console verbose before panic Date: Mon, 11 Feb 2019 15:18:32 +0100 Message-Id: <20190211141905.071750690@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141846.543045703@linuxfoundation.org> References: <20190211141846.543045703@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ 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 444b8b5dd69f..4a9191617076 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -112,8 +112,11 @@ 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, @@ -135,11 +138,6 @@ 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