From nobody Tue Sep 16 21:49:16 2025 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 E43A0C10F1B for ; Tue, 27 Dec 2022 16:15:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229985AbiL0QO0 (ORCPT ); Tue, 27 Dec 2022 11:14:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229588AbiL0QOX (ORCPT ); Tue, 27 Dec 2022 11:14:23 -0500 Received: from mx6.didiglobal.com (mx6.didiglobal.com [111.202.70.123]) by lindbergh.monkeyblade.net (Postfix) with SMTP id 16F1DCDC for ; Tue, 27 Dec 2022 08:14:21 -0800 (PST) Received: from mail.didiglobal.com (unknown [10.79.65.12]) by mx6.didiglobal.com (Maildata Gateway V2.8) with ESMTPS id A20A511002B812; Wed, 28 Dec 2022 00:14:17 +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 15.1.2375.34; Wed, 28 Dec 2022 00:14:17 +0800 Date: Wed, 28 Dec 2022 00:14:00 +0800 X-MD-Sfrom: tiozhang@didiglobal.com X-MD-SrcIP: 10.79.65.12 From: Tio Zhang To: , , , CC: , , , , Subject: [PATCH] sched: print parent comm in sched_show_task() Message-ID: <20221227161400.GA7646@didi-ThinkCentre-M930t-N000> Mail-Followup-To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, pmladek@suse.com, zyhtheonly@gmail.com, zyhtheonly@yeah.net, zwp10758@gmail.com MIME-Version: 1.0 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 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Knowing who the parent is might be useful for debugging. For example, we can sometimes resolve kernel hung tasks by stopping the person who begins those hung tasks. With the parent's name printed in sched_show_task(), it might be helpful to let people know which "service" should be operated. Signed-off-by: Tio Zhang --- kernel/sched/core.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index cb2aa2b54c7a..6f4aef0fed58 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8854,6 +8854,7 @@ void sched_show_task(struct task_struct *p) { unsigned long free =3D 0; int ppid; + char pcomm[TASK_COMM_LEN]; =20 if (!try_get_task_stack(p)) return; @@ -8867,11 +8868,13 @@ void sched_show_task(struct task_struct *p) #endif ppid =3D 0; rcu_read_lock(); - if (pid_alive(p)) + if (pid_alive(p)) { ppid =3D task_pid_nr(rcu_dereference(p->real_parent)); + get_task_comm(pcomm, rcu_dereference(p->real_parent)); + } rcu_read_unlock(); - pr_cont(" stack:%-5lu pid:%-5d ppid:%-6d flags:0x%08lx\n", - free, task_pid_nr(p), ppid, + pr_cont(" stack:%-5lu pid:%-5d ppid:%-6d parent:%-15.15s flags:0x%08lx\n", + free, task_pid_nr(p), ppid, pcomm, read_task_thread_flags(p)); =20 print_worker_info(KERN_INFO, p); --=20 2.17.1