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

Andrew Jeffery
2025-11-19T17:17:06Z

On Wed, 2025-10-15 at 14:36 +0800, lirongqing wrote:
> From: Li RongQing <lirongqing@baidu.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@baidu.com>
> Cc: Andrew Jeffery <andrew@codeconstruct.com.au>
> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Florian Wesphal <fw@strlen.de>
> Cc: Jakub Kacinski <kuba@kernel.org>
> Cc: Jason A. Donenfeld <jason@zx2c4.com>
> Cc: Joel Granados <joel.granados@kernel.org>
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Kees Cook <kees@kernel.org>
> Cc: Lance Yang <lance.yang@linux.dev>
> Cc: Liam Howlett <liam.howlett@oracle.com>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
> Cc: "Paul E . McKenney" <paulmck@kernel.org>
> Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: Phil Auld <pauld@redhat.com>
> Cc: Randy Dunlap <rdunlap@infradead.org>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Simon Horman <horms@kernel.org>
> Cc: Stanislav Fomichev <sdf@fomichev.me>
> Cc: Steven Rostedt <rostedt@goodmis.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@codeconstruct.com.au>