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=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 40C90C282C8 for ; Mon, 28 Jan 2019 15:59:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 114A021841 for ; Mon, 28 Jan 2019 15:59:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548691145; bh=m9Nd6wozWvbS3xYGcqT6sRCfFGHbUhm8r7D381lkRZc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fpffHvN1xrGmqKJ6S7X/NMucmfhzwXwjEZ+Yqj9DLrL58q+/uXpnTDepPik2vbeyS ilE5vj6LZhUP48ZKJF1+gRv3LUY+chk8KlgNZ6KzKG3LcHheNeHFsxui15u108rAzj vLTup5DAhRInYZU1pP/Vy0c+LqD2/rT3yzmXVQ7Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730517AbfA1P7D (ORCPT ); Mon, 28 Jan 2019 10:59:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:44380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730192AbfA1P7A (ORCPT ); Mon, 28 Jan 2019 10:59:00 -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 BF0142175B; Mon, 28 Jan 2019 15:58:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548691139; bh=m9Nd6wozWvbS3xYGcqT6sRCfFGHbUhm8r7D381lkRZc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RCZgV4VsOwoktB+T2NqRpoSCUNU0Ph1F+l7PpILwUDWvu3d4x6h6Boek7KGAQSQQr lMVKliZs53VZ+6YHTUDkcDLgt+5PR7/0fZC4cgvzwebKLqMMhFxv4ojkFTM/LUML4w KkYMQ3g8llt6a+kPy4bBtHOr7OcSEC4n5Gy6kOps= 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 4.20 299/304] kernel/hung_task.c: force console verbose before panic Date: Mon, 28 Jan 2019 10:43:36 -0500 Message-Id: <20190128154341.47195-299-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190128154341.47195-1-sashal@kernel.org> References: <20190128154341.47195-1-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 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