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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 5DA97C433ED for ; Wed, 19 May 2021 11:28:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E519611C2 for ; Wed, 19 May 2021 11:28:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350664AbhESLaR (ORCPT ); Wed, 19 May 2021 07:30:17 -0400 Received: from mx2.suse.de ([195.135.220.15]:59090 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229554AbhESLaQ (ORCPT ); Wed, 19 May 2021 07:30:16 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 4097EAF37; Wed, 19 May 2021 11:28:56 +0000 (UTC) Subject: Re: [PATCH] hungtask: add filter kthread/check comm To: chenguanyou , linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, keescook@chromium.org, mhocko@suse.com, lukas.bulwahn@gmail.com, gpiccoli@canonical.com, chenguanyou References: <20210518111616.26695-1-chenguanyou@xiaomi.com> From: Vlastimil Babka Message-ID: Date: Wed, 19 May 2021 13:28:55 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210518111616.26695-1-chenguanyou@xiaomi.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/18/21 1:16 PM, chenguanyou wrote: The description is missing. > Signed-off-by: chenguanyou > --- > include/linux/sched/sysctl.h | 4 ++++ > kernel/hung_task.c | 17 +++++++++++++++++ > kernel/sysctl.c | 15 +++++++++++++++ > lib/Kconfig.debug | 23 +++++++++++++++++++++++ > 4 files changed, 59 insertions(+) > > diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h > index 3c31ba88aca5..e8a9a28215bf 100644 > --- a/include/linux/sched/sysctl.h > +++ b/include/linux/sched/sysctl.h > @@ -14,11 +14,15 @@ extern unsigned int sysctl_hung_task_all_cpu_backtrace; > #define sysctl_hung_task_all_cpu_backtrace 0 > #endif /* CONFIG_SMP */ > > +#define TASK_COMM_LEN 16 > + > extern int sysctl_hung_task_check_count; > extern unsigned int sysctl_hung_task_panic; > extern unsigned long sysctl_hung_task_timeout_secs; > extern unsigned long sysctl_hung_task_check_interval_secs; > extern int sysctl_hung_task_warnings; > +extern unsigned int sysctl_hung_task_filter_kthread; > +extern char sysctl_hung_task_check_comm[TASK_COMM_LEN]; > int proc_dohung_task_timeout_secs(struct ctl_table *table, int write, > void *buffer, size_t *lenp, loff_t *ppos); > #else > diff --git a/kernel/hung_task.c b/kernel/hung_task.c > index 396ebaebea3f..e018563d4882 100644 > --- a/kernel/hung_task.c > +++ b/kernel/hung_task.c > @@ -23,6 +23,7 @@ > #include > > #include > +#include > > /* > * The number of tasks checked: > @@ -48,6 +49,16 @@ unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_ > */ > unsigned long __read_mostly sysctl_hung_task_check_interval_secs; > > +/* > + * Non zero means no checking kthread > + */ > +unsigned int __read_mostly sysctl_hung_task_filter_kthread = CONFIG_DEFAULT_HUNG_TASK_FILTER_KTHREAD; > + > +/* > + * Only one > + */ > +char __read_mostly sysctl_hung_task_check_comm[TASK_COMM_LEN] = CONFIG_DEFAULT_HUNG_TASK_CHECK_COMM; > + > int __read_mostly sysctl_hung_task_warnings = 10; > > static int __read_mostly did_panic; > @@ -88,6 +99,12 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) > { > unsigned long switch_count = t->nvcsw + t->nivcsw; > > + if (unlikely(strlen(sysctl_hung_task_check_comm) && !strstr(t->comm, sysctl_hung_task_check_comm))) > + return; > + > + if (unlikely(sysctl_hung_task_filter_kthread && t->flags & PF_KTHREAD)) > + return; > + > /* > * Ensure the task is not frozen. > * Also, skip vfork and any other user process that freezer should skip. > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 62fbd09b5dc1..157c47a8430a 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -2519,6 +2519,21 @@ static struct ctl_table kern_table[] = { > .proc_handler = proc_dointvec_minmax, > .extra1 = &neg_one, > }, > + { > + .procname = "hung_task_filter_kthread", > + .data = &sysctl_hung_task_filter_kthread, > + .maxlen = sizeof(int), > + .mode = 0644, > + .extra1 = SYSCTL_ZERO, > + .extra2 = SYSCTL_ONE, > + }, > + { > + .procname = "hung_task_check_comm", > + .data = &sysctl_hung_task_check_comm, > + .maxlen = TASK_COMM_LEN, > + .mode = 0644, > + .proc_handler = proc_dostring, > + }, > #endif > #ifdef CONFIG_RT_MUTEXES > { > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 2c7f46b366f1..59cfa9e230ee 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1101,6 +1101,29 @@ config DEFAULT_HUNG_TASK_TIMEOUT > A timeout of 0 disables the check. The default is two minutes. > Keeping the default should be fine in most cases. > > +config DEFAULT_HUNG_TASK_FILTER_KTHREAD > + bool "Default filter kthread for hung task" > + depends on DETECT_HUNG_TASK > + default 0 > + help > + This option controls filter kthread used to determine when > + a kernel task has become "state=TASK_UNINTERRUPTIBLE" and should be skip. > + > + It can be adjusted at runtime via the kernel.hung_task_filter_kthread > + sysctl or by writing a value to > + /proc/sys/kernel/hung_task_filter_kthread. > + > + A filter of 1 disables the check > + > +config DEFAULT_HUNG_TASK_CHECK_COMM > + string "Default check only one comm" > + depends on DETECT_HUNG_TASK > + default "" > + help > + It can be adjusted at runtime via the kernel.hung_task_check_comm > + sysctl or by writing a value to > + /proc/sys/kernel/hung_task_check_comm. > + > config BOOTPARAM_HUNG_TASK_PANIC > bool "Panic (Reboot) On Hung Tasks" > depends on DETECT_HUNG_TASK >