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

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

[lirongqing]

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 +-
 kernel/configs/debug.config                          |  2 +-
 kernel/hung_task.c                                   | 15 ++++++++++-----
 lib/Kconfig.debug                                    |  9 +++++----
 tools/testing/selftests/wireguard/qemu/kernel.config |  2 +-
 7 files changed, 36 insertions(+), 23 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a51ab46..492f0bc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1992,14 +1992,20 @@
 			the added memory block itself do not be affected.
 
 	hung_task_panic=
-			[KNL] Should the hung task detector generate panics.
-			Format: 0 | 1
+			[KNL] Number of hung tasks to trigger kernel panic.
+			Format: <int>
+
+			When set to a non-zero value, a kernel panic will be triggered if
+			the number of detected hung tasks reaches this value.
+
+			0: don't panic
+			1: panic immediately on first hung task
+			N: panic after N hung tasks are detected in a single scan
 
-			A value of 1 instructs the kernel to panic when a
-			hung task is detected. The default value is controlled
-			by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
-			option. The value selected by this boot parameter can
-			be changed later by the kernel.hung_task_panic sysctl.
+			The default value is controlled by the
+			CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value
+			selected by this boot parameter can be changed later by the
+			kernel.hung_task_panic sysctl.
 
 	hvc_iucv=	[S390]	Number of z/VM IUCV hypervisor console (HVC)
 				terminal devices. Valid values: 0..8
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index f3ee807..0065a55 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -397,13 +397,14 @@ a hung task is detected.
 hung_task_panic
 ===============
 
-Controls the kernel's behavior when a hung task is detected.
+When set to a non-zero value, a kernel panic will be triggered if the
+number of hung tasks found during a single scan reaches this value.
 This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled.
 
-= =================================================
+= =======================================================
 0 Continue operation. This is the default behavior.
-1 Panic immediately.
-= =================================================
+N Panic when N hung tasks are found during a single scan.
+= =======================================================
 
 
 hung_task_check_count
diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
index 61cee1e..c3b0d5f 100644
--- a/arch/arm/configs/aspeed_g5_defconfig
+++ b/arch/arm/configs/aspeed_g5_defconfig
@@ -308,7 +308,7 @@ CONFIG_PANIC_ON_OOPS=y
 CONFIG_PANIC_TIMEOUT=-1
 CONFIG_SOFTLOCKUP_DETECTOR=y
 CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y
-CONFIG_BOOTPARAM_HUNG_TASK_PANIC=y
+CONFIG_BOOTPARAM_HUNG_TASK_PANIC=1
 CONFIG_WQ_WATCHDOG=y
 # CONFIG_SCHED_DEBUG is not set
 CONFIG_FUNCTION_TRACER=y
diff --git a/kernel/configs/debug.config b/kernel/configs/debug.config
index e81327d..9f6ab7d 100644
--- a/kernel/configs/debug.config
+++ b/kernel/configs/debug.config
@@ -83,7 +83,7 @@ CONFIG_SLUB_DEBUG_ON=y
 #
 # Debug Oops, Lockups and Hangs
 #
-# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set
+CONFIG_BOOTPARAM_HUNG_TASK_PANIC=0
 # CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC is not set
 CONFIG_DEBUG_ATOMIC_SLEEP=y
 CONFIG_DETECT_HUNG_TASK=y
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index b2c1f14..84b4b04 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -81,7 +81,7 @@ static unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace;
  * hung task is detected:
  */
 static unsigned int __read_mostly sysctl_hung_task_panic =
-	IS_ENABLED(CONFIG_BOOTPARAM_HUNG_TASK_PANIC);
+	CONFIG_BOOTPARAM_HUNG_TASK_PANIC;
 
 static int
 hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
@@ -218,8 +218,11 @@ static inline void debug_show_blocker(struct task_struct *task, unsigned long ti
 }
 #endif
 
-static void check_hung_task(struct task_struct *t, unsigned long timeout)
+static void check_hung_task(struct task_struct *t, unsigned long timeout,
+		unsigned long prev_detect_count)
 {
+	unsigned long total_hung_task;
+
 	if (!task_is_hung(t, timeout))
 		return;
 
@@ -229,9 +232,10 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 	 */
 	sysctl_hung_task_detect_count++;
 
+	total_hung_task = sysctl_hung_task_detect_count - prev_detect_count;
 	trace_sched_process_hang(t);
 
-	if (sysctl_hung_task_panic) {
+	if (sysctl_hung_task_panic && total_hung_task >= sysctl_hung_task_panic) {
 		console_verbose();
 		hung_task_show_lock = true;
 		hung_task_call_panic = true;
@@ -300,6 +304,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
 	int max_count = sysctl_hung_task_check_count;
 	unsigned long last_break = jiffies;
 	struct task_struct *g, *t;
+	unsigned long prev_detect_count = sysctl_hung_task_detect_count;
 
 	/*
 	 * If the system crashed already then all bets are off,
@@ -320,7 +325,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
 			last_break = jiffies;
 		}
 
-		check_hung_task(t, timeout);
+		check_hung_task(t, timeout, prev_detect_count);
 	}
  unlock:
 	rcu_read_unlock();
@@ -389,7 +394,7 @@ static const struct ctl_table hung_task_sysctls[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
+		.extra2		= SYSCTL_INT_MAX,
 	},
 	{
 		.procname	= "hung_task_check_count",
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 3034e294..3976c90 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1258,12 +1258,13 @@ config DEFAULT_HUNG_TASK_TIMEOUT
 	  Keeping the default should be fine in most cases.
 
 config BOOTPARAM_HUNG_TASK_PANIC
-	bool "Panic (Reboot) On Hung Tasks"
+	int "Number of hung tasks to trigger kernel panic"
 	depends on DETECT_HUNG_TASK
+	default 0
 	help
-	  Say Y here to enable the kernel to panic on "hung tasks",
-	  which are bugs that cause the kernel to leave a task stuck
-	  in uninterruptible "D" state.
+	  When set to a non-zero value, a kernel panic will be triggered
+	  if the number of hung tasks found during a single scan reaches
+	  this value.
 
 	  The panic can be used in combination with panic_timeout,
 	  to cause the system to reboot automatically after a
diff --git a/tools/testing/selftests/wireguard/qemu/kernel.config b/tools/testing/selftests/wireguard/qemu/kernel.config
index 936b18b..0504c11 100644
--- a/tools/testing/selftests/wireguard/qemu/kernel.config
+++ b/tools/testing/selftests/wireguard/qemu/kernel.config
@@ -81,7 +81,7 @@ CONFIG_WQ_WATCHDOG=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y
 CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y
-CONFIG_BOOTPARAM_HUNG_TASK_PANIC=y
+CONFIG_BOOTPARAM_HUNG_TASK_PANIC=1
 CONFIG_PANIC_TIMEOUT=-1
 CONFIG_STACKTRACE=y
 CONFIG_EARLY_PRINTK=y
-- 
2.9.4

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

[Lance Yang]

LGTM. It works as expected, thanks!

On 2025/10/15 14:36, lirongqing wrote:
> From: Li RongQing <lirongqing@baidu.com>

For the commit message, I'd suggest the following for better clarity:

```
The hung_task_panic sysctl is currently a blunt instrument: it's all
or nothing.

Panicking on a single hung task can be an overreaction to a transient
glitch. A more reliable indicator of a systemic problem is when multiple
tasks hang simultaneously.

Extend hung_task_panic to accept an integer threshold, allowing the kernel
to panic only when N hung tasks are detected in a single scan. This
provides finer control to distinguish between isolated incidents and
system-wide failures.

The accepted values are:
- 0: Don't panic (unchanged)
- 1: Panic on the first hung task (unchanged)
- N > 1: Panic after N hung tasks are detected in a single scan

The original behavior is preserved for values 0 and 1, maintaining full
backward compatibility.
```

If you agree, likely no need to resend - Andrew could pick it up
directly when applying :)

> 
> 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>
> ---

So:

Reviewed-by: Lance Yang <lance.yang@linux.dev>
Tested-by: Lance Yang <lance.yang@linux.dev>

Cheers,
Lance

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

[Li,Rongqing]

> LGTM. It works as expected, thanks!
> 
> On 2025/10/15 14:36, lirongqing wrote:
> > From: Li RongQing <lirongqing@baidu.com>
> 
> For the commit message, I'd suggest the following for better clarity:
> 
> ```
> The hung_task_panic sysctl is currently a blunt instrument: it's all or nothing.
> 
> Panicking on a single hung task can be an overreaction to a transient glitch. A
> more reliable indicator of a systemic problem is when multiple tasks hang
> simultaneously.
> 
> Extend hung_task_panic to accept an integer threshold, allowing the kernel
> to panic only when N hung tasks are detected in a single scan. This provides
> finer control to distinguish between isolated incidents and system-wide
> failures.
> 
> The accepted values are:
> - 0: Don't panic (unchanged)
> - 1: Panic on the first hung task (unchanged)
> - N > 1: Panic after N hung tasks are detected in a single scan
> 
> The original behavior is preserved for values 0 and 1, maintaining full
> backward compatibility.
> ```
> 
> If you agree, likely no need to resend - Andrew could pick it up directly when
> applying :)
> 

This is better;

Andrew, could you pick it up directly

Thanks

-Li

> >
> > 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>
> > ---
> 
> So:
> 
> Reviewed-by: Lance Yang <lance.yang@linux.dev>
> Tested-by: Lance Yang <lance.yang@linux.dev>
> 
> Cheers,
> Lance

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

[Masami Hiramatsu]

On Wed, 15 Oct 2025 14:36:15 +0800
lirongqing <lirongqing@baidu.com> 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.

Looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thank you,

> 
> 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 +-
>  kernel/configs/debug.config                          |  2 +-
>  kernel/hung_task.c                                   | 15 ++++++++++-----
>  lib/Kconfig.debug                                    |  9 +++++----
>  tools/testing/selftests/wireguard/qemu/kernel.config |  2 +-
>  7 files changed, 36 insertions(+), 23 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a51ab46..492f0bc 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1992,14 +1992,20 @@
>  			the added memory block itself do not be affected.
>  
>  	hung_task_panic=
> -			[KNL] Should the hung task detector generate panics.
> -			Format: 0 | 1
> +			[KNL] Number of hung tasks to trigger kernel panic.
> +			Format: <int>
> +
> +			When set to a non-zero value, a kernel panic will be triggered if
> +			the number of detected hung tasks reaches this value.
> +
> +			0: don't panic
> +			1: panic immediately on first hung task
> +			N: panic after N hung tasks are detected in a single scan
>  
> -			A value of 1 instructs the kernel to panic when a
> -			hung task is detected. The default value is controlled
> -			by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
> -			option. The value selected by this boot parameter can
> -			be changed later by the kernel.hung_task_panic sysctl.
> +			The default value is controlled by the
> +			CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value
> +			selected by this boot parameter can be changed later by the
> +			kernel.hung_task_panic sysctl.
>  
>  	hvc_iucv=	[S390]	Number of z/VM IUCV hypervisor console (HVC)
>  				terminal devices. Valid values: 0..8
> diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
> index f3ee807..0065a55 100644
> --- a/Documentation/admin-guide/sysctl/kernel.rst
> +++ b/Documentation/admin-guide/sysctl/kernel.rst
> @@ -397,13 +397,14 @@ a hung task is detected.
>  hung_task_panic
>  ===============
>  
> -Controls the kernel's behavior when a hung task is detected.
> +When set to a non-zero value, a kernel panic will be triggered if the
> +number of hung tasks found during a single scan reaches this value.
>  This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled.
>  
> -= =================================================
> += =======================================================
>  0 Continue operation. This is the default behavior.
> -1 Panic immediately.
> -= =================================================
> +N Panic when N hung tasks are found during a single scan.
> += =======================================================
>  
>  
>  hung_task_check_count
> diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
> index 61cee1e..c3b0d5f 100644
> --- a/arch/arm/configs/aspeed_g5_defconfig
> +++ b/arch/arm/configs/aspeed_g5_defconfig
> @@ -308,7 +308,7 @@ CONFIG_PANIC_ON_OOPS=y
>  CONFIG_PANIC_TIMEOUT=-1
>  CONFIG_SOFTLOCKUP_DETECTOR=y
>  CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y
> -CONFIG_BOOTPARAM_HUNG_TASK_PANIC=y
> +CONFIG_BOOTPARAM_HUNG_TASK_PANIC=1
>  CONFIG_WQ_WATCHDOG=y
>  # CONFIG_SCHED_DEBUG is not set
>  CONFIG_FUNCTION_TRACER=y
> diff --git a/kernel/configs/debug.config b/kernel/configs/debug.config
> index e81327d..9f6ab7d 100644
> --- a/kernel/configs/debug.config
> +++ b/kernel/configs/debug.config
> @@ -83,7 +83,7 @@ CONFIG_SLUB_DEBUG_ON=y
>  #
>  # Debug Oops, Lockups and Hangs
>  #
> -# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set
> +CONFIG_BOOTPARAM_HUNG_TASK_PANIC=0
>  # CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC is not set
>  CONFIG_DEBUG_ATOMIC_SLEEP=y
>  CONFIG_DETECT_HUNG_TASK=y
> diff --git a/kernel/hung_task.c b/kernel/hung_task.c
> index b2c1f14..84b4b04 100644
> --- a/kernel/hung_task.c
> +++ b/kernel/hung_task.c
> @@ -81,7 +81,7 @@ static unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace;
>   * hung task is detected:
>   */
>  static unsigned int __read_mostly sysctl_hung_task_panic =
> -	IS_ENABLED(CONFIG_BOOTPARAM_HUNG_TASK_PANIC);
> +	CONFIG_BOOTPARAM_HUNG_TASK_PANIC;
>  
>  static int
>  hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
> @@ -218,8 +218,11 @@ static inline void debug_show_blocker(struct task_struct *task, unsigned long ti
>  }
>  #endif
>  
> -static void check_hung_task(struct task_struct *t, unsigned long timeout)
> +static void check_hung_task(struct task_struct *t, unsigned long timeout,
> +		unsigned long prev_detect_count)
>  {
> +	unsigned long total_hung_task;
> +
>  	if (!task_is_hung(t, timeout))
>  		return;
>  
> @@ -229,9 +232,10 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
>  	 */
>  	sysctl_hung_task_detect_count++;
>  
> +	total_hung_task = sysctl_hung_task_detect_count - prev_detect_count;
>  	trace_sched_process_hang(t);
>  
> -	if (sysctl_hung_task_panic) {
> +	if (sysctl_hung_task_panic && total_hung_task >= sysctl_hung_task_panic) {
>  		console_verbose();
>  		hung_task_show_lock = true;
>  		hung_task_call_panic = true;
> @@ -300,6 +304,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
>  	int max_count = sysctl_hung_task_check_count;
>  	unsigned long last_break = jiffies;
>  	struct task_struct *g, *t;
> +	unsigned long prev_detect_count = sysctl_hung_task_detect_count;
>  
>  	/*
>  	 * If the system crashed already then all bets are off,
> @@ -320,7 +325,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
>  			last_break = jiffies;
>  		}
>  
> -		check_hung_task(t, timeout);
> +		check_hung_task(t, timeout, prev_detect_count);
>  	}
>   unlock:
>  	rcu_read_unlock();
> @@ -389,7 +394,7 @@ static const struct ctl_table hung_task_sysctls[] = {
>  		.mode		= 0644,
>  		.proc_handler	= proc_dointvec_minmax,
>  		.extra1		= SYSCTL_ZERO,
> -		.extra2		= SYSCTL_ONE,
> +		.extra2		= SYSCTL_INT_MAX,
>  	},
>  	{
>  		.procname	= "hung_task_check_count",
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 3034e294..3976c90 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1258,12 +1258,13 @@ config DEFAULT_HUNG_TASK_TIMEOUT
>  	  Keeping the default should be fine in most cases.
>  
>  config BOOTPARAM_HUNG_TASK_PANIC
> -	bool "Panic (Reboot) On Hung Tasks"
> +	int "Number of hung tasks to trigger kernel panic"
>  	depends on DETECT_HUNG_TASK
> +	default 0
>  	help
> -	  Say Y here to enable the kernel to panic on "hung tasks",
> -	  which are bugs that cause the kernel to leave a task stuck
> -	  in uninterruptible "D" state.
> +	  When set to a non-zero value, a kernel panic will be triggered
> +	  if the number of hung tasks found during a single scan reaches
> +	  this value.
>  
>  	  The panic can be used in combination with panic_timeout,
>  	  to cause the system to reboot automatically after a
> diff --git a/tools/testing/selftests/wireguard/qemu/kernel.config b/tools/testing/selftests/wireguard/qemu/kernel.config
> index 936b18b..0504c11 100644
> --- a/tools/testing/selftests/wireguard/qemu/kernel.config
> +++ b/tools/testing/selftests/wireguard/qemu/kernel.config
> @@ -81,7 +81,7 @@ CONFIG_WQ_WATCHDOG=y
>  CONFIG_DETECT_HUNG_TASK=y
>  CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y
>  CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y
> -CONFIG_BOOTPARAM_HUNG_TASK_PANIC=y
> +CONFIG_BOOTPARAM_HUNG_TASK_PANIC=1
>  CONFIG_PANIC_TIMEOUT=-1
>  CONFIG_STACKTRACE=y
>  CONFIG_EARLY_PRINTK=y
> -- 
> 2.9.4
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

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

[Paul Menzel]

Dear RongQing,


Thank you for the patch. One minor comment regarding the Kconfig 
description.

Am 15.10.25 um 08:36 schrieb lirongqing:
> 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 +-
>   kernel/configs/debug.config                          |  2 +-
>   kernel/hung_task.c                                   | 15 ++++++++++-----
>   lib/Kconfig.debug                                    |  9 +++++----
>   tools/testing/selftests/wireguard/qemu/kernel.config |  2 +-
>   7 files changed, 36 insertions(+), 23 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a51ab46..492f0bc 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1992,14 +1992,20 @@
>   			the added memory block itself do not be affected.
>   
>   	hung_task_panic=
> -			[KNL] Should the hung task detector generate panics.
> -			Format: 0 | 1
> +			[KNL] Number of hung tasks to trigger kernel panic.
> +			Format: <int>
> +
> +			When set to a non-zero value, a kernel panic will be triggered if
> +			the number of detected hung tasks reaches this value.
> +
> +			0: don't panic
> +			1: panic immediately on first hung task
> +			N: panic after N hung tasks are detected in a single scan
>   
> -			A value of 1 instructs the kernel to panic when a
> -			hung task is detected. The default value is controlled
> -			by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
> -			option. The value selected by this boot parameter can
> -			be changed later by the kernel.hung_task_panic sysctl.
> +			The default value is controlled by the
> +			CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value
> +			selected by this boot parameter can be changed later by the
> +			kernel.hung_task_panic sysctl.
>   
>   	hvc_iucv=	[S390]	Number of z/VM IUCV hypervisor console (HVC)
>   				terminal devices. Valid values: 0..8
> diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
> index f3ee807..0065a55 100644
> --- a/Documentation/admin-guide/sysctl/kernel.rst
> +++ b/Documentation/admin-guide/sysctl/kernel.rst
> @@ -397,13 +397,14 @@ a hung task is detected.
>   hung_task_panic
>   ===============
>   
> -Controls the kernel's behavior when a hung task is detected.
> +When set to a non-zero value, a kernel panic will be triggered if the
> +number of hung tasks found during a single scan reaches this value.
>   This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled.
>   
> -= =================================================
> += =======================================================
>   0 Continue operation. This is the default behavior.
> -1 Panic immediately.
> -= =================================================
> +N Panic when N hung tasks are found during a single scan.
> += =======================================================
>   
>   
>   hung_task_check_count

[…]

> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 3034e294..3976c90 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1258,12 +1258,13 @@ config DEFAULT_HUNG_TASK_TIMEOUT
>   	  Keeping the default should be fine in most cases.
>   
>   config BOOTPARAM_HUNG_TASK_PANIC
> -	bool "Panic (Reboot) On Hung Tasks"
> +	int "Number of hung tasks to trigger kernel panic"
>   	depends on DETECT_HUNG_TASK
> +	default 0
>   	help
> -	  Say Y here to enable the kernel to panic on "hung tasks",
> -	  which are bugs that cause the kernel to leave a task stuck
> -	  in uninterruptible "D" state.
> +	  When set to a non-zero value, a kernel panic will be triggered
> +	  if the number of hung tasks found during a single scan reaches
> +	  this value.
>   
>   	  The panic can be used in combination with panic_timeout,
>   	  to cause the system to reboot automatically after a
Why not leave the sentence about the uninterruptible "D" state in there?

Also, it sounds like, some are actually using this in production. Maybe 
it should be moved out of `Kconfig.debug` too?


Kind regards,

Paul

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

[Andrew Morton]

On Thu, 16 Oct 2025 05:57:34 +0000 "Li,Rongqing" <lirongqing@baidu.com> wrote:

> > If you agree, likely no need to resend - Andrew could pick it up directly when
> > applying :)
> > 
> 
> This is better;
> 
> Andrew, could you pick it up directly

No problems, thanks.

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

[Li,Rongqing]

> 
> Am 15.10.25 um 08:36 schrieb lirongqing:
> > 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 +-
> >   kernel/configs/debug.config                          |  2 +-
> >   kernel/hung_task.c                                   | 15
> ++++++++++-----
> >   lib/Kconfig.debug                                    |  9
> +++++----
> >   tools/testing/selftests/wireguard/qemu/kernel.config |  2 +-
> >   7 files changed, 36 insertions(+), 23 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt
> > b/Documentation/admin-guide/kernel-parameters.txt
> > index a51ab46..492f0bc 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -1992,14 +1992,20 @@
> >   			the added memory block itself do not be affected.
> >
> >   	hung_task_panic=
> > -			[KNL] Should the hung task detector generate panics.
> > -			Format: 0 | 1
> > +			[KNL] Number of hung tasks to trigger kernel panic.
> > +			Format: <int>
> > +
> > +			When set to a non-zero value, a kernel panic will be triggered
> if
> > +			the number of detected hung tasks reaches this value.
> > +
> > +			0: don't panic
> > +			1: panic immediately on first hung task
> > +			N: panic after N hung tasks are detected in a single scan
> >
> > -			A value of 1 instructs the kernel to panic when a
> > -			hung task is detected. The default value is controlled
> > -			by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
> > -			option. The value selected by this boot parameter can
> > -			be changed later by the kernel.hung_task_panic sysctl.
> > +			The default value is controlled by the
> > +			CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option.
> The value
> > +			selected by this boot parameter can be changed later by the
> > +			kernel.hung_task_panic sysctl.
> >
> >   	hvc_iucv=	[S390]	Number of z/VM IUCV hypervisor console
> (HVC)
> >   				terminal devices. Valid values: 0..8 diff --git
> > a/Documentation/admin-guide/sysctl/kernel.rst
> > b/Documentation/admin-guide/sysctl/kernel.rst
> > index f3ee807..0065a55 100644
> > --- a/Documentation/admin-guide/sysctl/kernel.rst
> > +++ b/Documentation/admin-guide/sysctl/kernel.rst
> > @@ -397,13 +397,14 @@ a hung task is detected.
> >   hung_task_panic
> >   ===============
> >
> > -Controls the kernel's behavior when a hung task is detected.
> > +When set to a non-zero value, a kernel panic will be triggered if the
> > +number of hung tasks found during a single scan reaches this value.
> >   This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled.
> >
> > -= =================================================
> > += =======================================================
> >   0 Continue operation. This is the default behavior.
> > -1 Panic immediately.
> > -= =================================================
> > +N Panic when N hung tasks are found during a single scan.
> > += =======================================================
> >
> >
> >   hung_task_check_count
> 
> […]
> 
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index
> > 3034e294..3976c90 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -1258,12 +1258,13 @@ config DEFAULT_HUNG_TASK_TIMEOUT
> >   	  Keeping the default should be fine in most cases.
> >
> >   config BOOTPARAM_HUNG_TASK_PANIC
> > -	bool "Panic (Reboot) On Hung Tasks"
> > +	int "Number of hung tasks to trigger kernel panic"
> >   	depends on DETECT_HUNG_TASK
> > +	default 0
> >   	help
> > -	  Say Y here to enable the kernel to panic on "hung tasks",
> > -	  which are bugs that cause the kernel to leave a task stuck
> > -	  in uninterruptible "D" state.
> > +	  When set to a non-zero value, a kernel panic will be triggered
> > +	  if the number of hung tasks found during a single scan reaches
> > +	  this value.
> >
> >   	  The panic can be used in combination with panic_timeout,
> >   	  to cause the system to reboot automatically after a
> Why not leave the sentence about the uninterruptible "D" state in there?
> 
This seem to say a kernel bug to cause hung task, but it maybe hardware failure(or virtio backend bug); so I do not keep it

> Also, it sounds like, some are actually using this in production. Maybe it
> should be moved out of `Kconfig.debug` too?
> 

I think hung task panic is a useful feature, it should move out of Kconfig.debug

Thanks

-Li

> 
> Kind regards,
> 
> Paul

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

[Andrew Jeffery]

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>