linux-kernel - Re: [PATCH][v4] hung_task: Panic when there are more than N hung tasks at the same time

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Message-ID: <57dffe112a461a218c7dab6bfc3b02967440cc77.camel@codeconstruct.com.au>
Date: Fri, 17 Oct 2025 15:47:45 +1030
From: Andrew Jeffery <andrew@...econstruct.com.au>
To: lirongqing <lirongqing@...du.com>, Andrew Morton
 <akpm@...ux-foundation.org>,  Lance Yang <lance.yang@...ux.dev>, Masami
 Hiramatsu <mhiramat@...nel.org>, linux-kernel@...r.kernel.org
Cc: linux-doc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-aspeed@...ts.ozlabs.org, wireguard@...ts.zx2c4.com,
 netdev@...r.kernel.org, 	linux-kselftest@...r.kernel.org, Anshuman Khandual
 <anshuman.khandual@....com>,  Arnd Bergmann	 <arnd@...db.de>, David
 Hildenbrand <david@...hat.com>, Florian Wesphal	 <fw@...len.de>, Jakub
 Kacinski <kuba@...nel.org>, "Jason A . Donenfeld"	 <jason@...c4.com>, Joel
 Granados <joel.granados@...nel.org>, Joel Stanley	 <joel@....id.au>,
 Jonathan Corbet <corbet@....net>, Kees Cook <kees@...nel.org>,  Liam
 Howlett <liam.howlett@...cle.com>, Lorenzo Stoakes
 <lorenzo.stoakes@...cle.com>, "Paul E . McKenney"	 <paulmck@...nel.org>,
 Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, Petr Mladek
 <pmladek@...e.com>, Phil Auld <pauld@...hat.com>, Randy Dunlap
 <rdunlap@...radead.org>,  Russell King <linux@...linux.org.uk>, Shuah Khan
 <shuah@...nel.org>, Simon Horman <horms@...nel.org>,  Stanislav Fomichev	
 <sdf@...ichev.me>, Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH][v4] hung_task: Panic when there are more than N hung
 tasks at the same time

On Wed, 2025-10-15 at 14:36 +0800, lirongqing wrote:
> From: Li RongQing <lirongqing@...du.com>
> 
> Currently, when 'hung_task_panic' is enabled, the kernel panics
> immediately upon detecting the first hung task. However, some hung
> tasks are transient and allow system recovery, while persistent hangs
> should trigger a panic when accumulating beyond a threshold.
> 
> Extend the 'hung_task_panic' sysctl to accept a threshold value
> specifying the number of hung tasks that must be detected before
> triggering a kernel panic. This provides finer control for environments
> where transient hangs may occur but persistent hangs should be fatal.
> 
> The sysctl now accepts:
> - 0: don't panic (maintains original behavior)
> - 1: panic on first hung task (maintains original behavior)
> - N > 1: panic after N hung tasks are detected in a single scan
> 
> This maintains backward compatibility while providing flexibility for
> different hang scenarios.
> 
> Signed-off-by: Li RongQing <lirongqing@...du.com>
> Cc: Andrew Jeffery <andrew@...econstruct.com.au>
> Cc: Anshuman Khandual <anshuman.khandual@....com>
> Cc: Arnd Bergmann <arnd@...db.de>
> Cc: David Hildenbrand <david@...hat.com>
> Cc: Florian Wesphal <fw@...len.de>
> Cc: Jakub Kacinski <kuba@...nel.org>
> Cc: Jason A. Donenfeld <jason@...c4.com>
> Cc: Joel Granados <joel.granados@...nel.org>
> Cc: Joel Stanley <joel@....id.au>
> Cc: Jonathan Corbet <corbet@....net>
> Cc: Kees Cook <kees@...nel.org>
> Cc: Lance Yang <lance.yang@...ux.dev>
> Cc: Liam Howlett <liam.howlett@...cle.com>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
> Cc: "Masami Hiramatsu (Google)" <mhiramat@...nel.org>
> Cc: "Paul E . McKenney" <paulmck@...nel.org>
> Cc: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
> Cc: Petr Mladek <pmladek@...e.com>
> Cc: Phil Auld <pauld@...hat.com>
> Cc: Randy Dunlap <rdunlap@...radead.org>
> Cc: Russell King <linux@...linux.org.uk>
> Cc: Shuah Khan <shuah@...nel.org>
> Cc: Simon Horman <horms@...nel.org>
> Cc: Stanislav Fomichev <sdf@...ichev.me>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> ---
> diff with v3: comments modification, suggested by Lance, Masami, Randy and Petr
> diff with v2: do not add a new sysctl, extend hung_task_panic, suggested by Kees Cook
> 
>  Documentation/admin-guide/kernel-parameters.txt      | 20 +++++++++++++-------
>  Documentation/admin-guide/sysctl/kernel.rst          |  9 +++++----
>  arch/arm/configs/aspeed_g5_defconfig                 |  2 +-

For the aspeed_g5_defconfig change:

Acked-by: Andrew Jeffery <andrew@...econstruct.com.au>