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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4116C43219 for ; Thu, 24 Nov 2022 11:27:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229788AbiKXL1s (ORCPT ); Thu, 24 Nov 2022 06:27:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230079AbiKXL1l (ORCPT ); Thu, 24 Nov 2022 06:27:41 -0500 X-Greylist: delayed 121 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 24 Nov 2022 03:27:39 PST Received: from mx5.didiglobal.com (mx5.didiglobal.com [111.202.70.122]) by lindbergh.monkeyblade.net (Postfix) with SMTP id D3FD511466 for ; Thu, 24 Nov 2022 03:27:37 -0800 (PST) Received: from mail.didiglobal.com (unknown [10.79.65.12]) by mx5.didiglobal.com (Maildata Gateway V2.8) with ESMTPS id ECB8CB0148E0B; Thu, 24 Nov 2022 19:25:33 +0800 (CST) Received: from didi-ThinkCentre-M930t-N000 (10.79.64.101) by ZJY02-ACTMBX-02.didichuxing.com (10.79.65.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.17; Thu, 24 Nov 2022 19:25:33 +0800 Date: Thu, 24 Nov 2022 19:25:26 +0800 X-MD-Sfrom: tiozhang@didiglobal.com X-MD-SrcIP: 10.79.65.12 From: Tio Zhang To: , , CC: , Subject: [PATCH] kernel/hung_task: print real_parent->comm, pid in check_hung_task Message-ID: <20221124112526.GA21832@didi-ThinkCentre-M930t-N000> Mail-Followup-To: pmladek@suse.com, akpm@linux-foundation.org, peterz@infradead.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [10.79.64.101] X-ClientProxiedBy: ZJY03-PUBMBX-01.didichuxing.com (10.79.71.12) To ZJY02-ACTMBX-02.didichuxing.com (10.79.65.12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We can avoid a hung task by fixing the process who causes it. But sometimes it is difficult to find out which service the bad process belongs to by only knowing its pid and comm. Since userspace tools to learn who launches the bad process do not always work when we get a hung task, it is helpful printing the parent by kernel. Signed-off-by: Tio Zhang --- kernel/hung_task.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index c71889f3f3fc..33543d27bd5c 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -89,6 +89,7 @@ static struct notifier_block panic_block = { static void check_hung_task(struct task_struct *t, unsigned long timeout) { + struct task_struct *p = t->real_parent; unsigned long switch_count = t->nvcsw + t->nivcsw; /* @@ -129,8 +130,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) if (sysctl_hung_task_warnings) { if (sysctl_hung_task_warnings > 0) sysctl_hung_task_warnings--; - pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n", - t->comm, t->pid, (jiffies - t->last_switch_time) / HZ); + pr_err("INFO: task %s:%d, parent %s:%d blocked for more than %ld seconds.\n", + t->comm, t->pid, p->comm, p->pid, (jiffies - t->last_switch_time) / HZ); pr_err(" %s %s %.*s\n", print_tainted(), init_utsname()->release, (int)strcspn(init_utsname()->version, " "), -- 2.17.1