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bh=O/9q39k7rrXMli4TaFIIEmk8ITDHDiphSH3DMEqJGCo=; b=HRAYdOtEht39NFSwSoG4YSj3/aWXKdTVZhduamz4bBOu7pR2urv0Bb9tJABZH8igDm TDTT16Ra85+3yPlwGj0huTJ+fPB1r/EiGAgUUVA32lGH2zJMQuwpmpnWKYUGA1zmq4dJ C8CpcjWgRC1KOvy13VODKbz8ATEZjQFVmQIp+6AOgyVC36uC7MxrgKCKus0PtUtveSJi 8vtJ5JgVjdqU5IFTVu7qPmOstHRjFe6ye730rf8lM8iY/pdRZt7kw2nXApE1yew0ZF1i mJ3YCzEkOH4EagnHVY8DMNQyAyUImmTVTbUN1dD2b/9nYa+CYQGJnKo6X7lKUE9umQSm mFRA== X-Gm-Message-State: AOAM533GRtPI4UCUjJEhLKK95PfzOfASqm1hg6WzUSWtwUoEWZCjleMk 8Jzcdhv+ulqixn+WsjXGrgl9hHBCFYtqNESI X-Google-Smtp-Source: ABdhPJySESpCrQ5eCg0kOU5AT26GaTmqmYnoNugA9kucM0CeA7UQtCxPvSgYxth+m3GW3xgcqdzXoA== X-Received: by 2002:a05:6a00:14d0:b029:2cf:ee47:dfd9 with SMTP id w16-20020a056a0014d0b02902cfee47dfd9mr10487950pfu.31.1621426418688; Wed, 19 May 2021 05:13:38 -0700 (PDT) Received: from mi-HP-ProDesk-600-G5-PCI-MT.mioffice.cn ([43.224.245.180]) by smtp.gmail.com with ESMTPSA id iq16sm5989049pjb.31.2021.05.19.05.13.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 May 2021 05:13:38 -0700 (PDT) From: chenguanyou X-Google-Original-From: chenguanyou To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, keescook@chromium.org, mhocko@suse.com, lukas.bulwahn@gmail.com, vbabka@suse.cz, gpiccoli@canonical.com, chenguanyou Subject: [PATCH] hungtask: add filter kthread/check comm Date: Wed, 19 May 2021 20:13:25 +0800 Message-Id: <20210519121325.22083-1-chenguanyou@xiaomi.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some kernel threads are always in D state, when we enable hung_task, it will misjudge, we should skip these to narrow the scope. exp mtk mobilephone: root 420 420 2 0 0 kwdt_thread 0 D wdtk-0 root 421 421 2 0 0 kwdt_thread 0 D wdtk-1 root 422 422 2 0 0 kwdt_thread 0 D wdtk-2 root 423 423 2 0 0 kwdt_thread 0 D wdtk-3 root 424 424 2 0 0 kwdt_thread 0 D wdtk-4 root 425 425 2 0 0 kwdt_thread 0 D wdtk-5 root 426 426 2 0 0 kwdt_thread 0 D wdtk-6 root 427 427 2 0 0 kwdt_thread 0 D wdtk-7 root 435 435 2 0 0 mtk_lpm_monitor_thread 0 D LPM-0 root 436 436 2 0 0 mtk_lpm_monitor_thread 0 D LPM-1 root 437 437 2 0 0 mtk_lpm_monitor_thread 0 D LPM-2 root 438 438 2 0 0 mtk_lpm_monitor_thread 0 D LPM-3 root 439 439 2 0 0 mtk_lpm_monitor_thread 0 D LPM-4 root 440 440 2 0 0 mtk_lpm_monitor_thread 0 D LPM-5 root 441 441 2 0 0 mtk_lpm_monitor_thread 0 D LPM-6 root 442 442 2 0 0 mtk_lpm_monitor_thread 0 D LPM-7 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 -- 2.17.1