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 <[email protected]>
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 <[email protected]>
Cc: Andrew Jeffery <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Florian Wesphal <[email protected]>
Cc: Jakub Kacinski <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Joel Granados <[email protected]>
Cc: Joel Stanley <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: "Masami Hiramatsu (Google)" <[email protected]>
Cc: "Paul E . McKenney" <[email protected]>
Cc: Pawan Gupta <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Phil Auld <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Russell King <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Simon Horman <[email protected]>
Cc: Stanislav Fomichev <[email protected]>
Cc: Steven Rostedt <[email protected]>
---
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
