From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10FF521E08D for ; Tue, 16 Dec 2025 03:38:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765856290; cv=none; b=BD1JAoY6/ilZU7wdL+VngVRjCAxpldqmlupIp6LI4mAwF9L+0qNOwgzZqdWIvWsu5+SSg9odcOUB3YZHwBJhkton7c012mymnZf1CZfIZFiBmhUSUajA2ktp/FsT9wbQPP1iRB7jG+IGVRLVMa7+unq8HB/F2gtmdqNFB3Nc0zc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765856290; c=relaxed/simple; bh=NwNqfXEYgLRsQfZP99zzh7Vf28ssTVwA0SS3CAGqGy8=; h=Date:To:From:Subject:Message-Id; b=Xn1ClAeXLJMA2hAg19p4hGQ2j8cg+iSin6c1yI5y4BH97S/SVzKHELGZrv6M622RxMXVO+tGjOTx7niOuIMfra871hSLYo4Ebms6DWuqpFgieIH9uVLLh+wOzDM0hmkdP7oFCLKGlc2+9VJVk1nmLmKttmnRvWx/t5v/i1w3alI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=c2TLosf4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="c2TLosf4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B31AC4CEF5; Tue, 16 Dec 2025 03:38:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1765856289; bh=NwNqfXEYgLRsQfZP99zzh7Vf28ssTVwA0SS3CAGqGy8=; h=Date:To:From:Subject:From; b=c2TLosf4n8a7dTKaKEZA8Q2KFGj6NaKU1hKe6JB5Nt62hVLaUmGrFkhU3uy1TDgFG /l5p74BUHMCYwvwhcy9FE+a7cw3JW8/3tQlGi4nkOdDKEa6X/C1m3bjNjDbhjm2sFZ vLHNEsSbIJG8VuXbub4EbeyFXhMdqD+0DuUWJR0Y= Date: Mon, 15 Dec 2025 19:38:09 -0800 To: mm-commits@vger.kernel.org,pmladek@suse.com,mhiramat@kernel.org,lance.yang@linux.dev,gregkh@linuxfoundation.org,atomlin@atomlin.com,akpm@linux-foundation.org From: Andrew Morton Subject: + hung_task-enable-runtime-reset-of-hung_task_detect_count.patch added to mm-nonmm-unstable branch Message-Id: <20251216033809.8B31AC4CEF5@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: hung_task: enable runtime reset of hung_task_detect_count has been added to the -mm mm-nonmm-unstable branch. Its filename is hung_task-enable-runtime-reset-of-hung_task_detect_count.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/hung_task-enable-runtime-reset-of-hung_task_detect_count.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Aaron Tomlin Subject: hung_task: enable runtime reset of hung_task_detect_count Date: Mon, 15 Dec 2025 22:00:36 -0500 Introduce support for writing to /proc/sys/kernel/hung_task_detect_count. Writing any value to this file atomically resets the counter of detected hung tasks to zero. This grants system administrators the ability to clear the cumulative diagnostic history after resolving an incident, simplifying monitoring without requiring a system restart. Link: https://lkml.kernel.org/r/20251216030036.1822217-3-atomlin@atomlin.com Signed-off-by: Aaron Tomlin Cc: Greg Kroah-Hartman Cc: Lance Yang Cc: "Masami Hiramatsu (Google)" Cc: Petr Mladek Signed-off-by: Andrew Morton --- Documentation/admin-guide/sysctl/kernel.rst | 2 - kernel/hung_task.c | 29 ++++++++++++++++-- 2 files changed, 28 insertions(+), 3 deletions(-) --- a/Documentation/admin-guide/sysctl/kernel.rst~hung_task-enable-runtime-reset-of-hung_task_detect_count +++ a/Documentation/admin-guide/sysctl/kernel.rst @@ -418,7 +418,7 @@ hung_task_detect_count ====================== Indicates the total number of tasks that have been detected as hung since -the system boot. +the system boot. The counter can be reset to zero when written to. This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled. --- a/kernel/hung_task.c~hung_task-enable-runtime-reset-of-hung_task_detect_count +++ a/kernel/hung_task.c @@ -375,6 +375,31 @@ static long hung_timeout_jiffies(unsigne } #ifdef CONFIG_SYSCTL + +/** + * proc_dohung_task_detect_count - proc handler for hung_task_detect_count + * @table: Pointer to the struct ctl_table definition for this proc entry + * @write: Flag indicating the operation + * @buffer: User space buffer for data transfer + * @lenp: Pointer to the length of the data being transferred + * @ppos: Pointer to the current file offset + * + * This handler is used for reading the current hung task detection count + * and for resetting it to zero when a write operation is performed. + * Returns 0 on success or a negative error code on failure. + */ +static int proc_dohung_task_detect_count(const struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + if (!write) + return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); + + WRITE_ONCE(sysctl_hung_task_detect_count, 0); + *ppos += *lenp; + + return 0; +} + /* * Process updating of timeout sysctl */ @@ -457,8 +482,8 @@ static const struct ctl_table hung_task_ .procname = "hung_task_detect_count", .data = &sysctl_hung_task_detect_count, .maxlen = sizeof(unsigned long), - .mode = 0444, - .proc_handler = proc_doulongvec_minmax, + .mode = 0644, + .proc_handler = proc_dohung_task_detect_count, }, { .procname = "hung_task_sys_info", _ Patches currently in -mm which might be from atomlin@atomlin.com are hung_task-introduce-helper-for-hung-task-warning.patch hung_task-enable-runtime-reset-of-hung_task_detect_count.patch