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Documentation: Better document the hardlockup_panic sysctl

PATCH Applied Scott Wood 4 participants 4 messages Dec 10, 2017 – Dec 11, 2017 Documentation

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Scott Wood

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PATCH 1/1 Documentation: Better document the hardlockup_panic sysctl

Commit ac1f591249d95372f ("kernel/watchdog.c: add sysctl knob hardlockup_panic") added the hardlockup_panic sysctl, but did not add it to Documentation/sysctl/kernel.txt. Add this, and reference it from the corresponding entry in Documentation/admin-guide/kernel-parameters.txt.

---
 Documentation/admin-guide/kernel-parameters.txt |  3 +++
 Documentation/sysctl/kernel.txt                 | 14 ++++++++++++++
 2 files changed, 17 insertions(+)
Documentation/admin-guide/kernel-parameters.txt +3 -0
index 6571fbfdb2a1..dfb7c35b5826 100644
@@ -2538,6 +2538,9 @@
 			This is useful when you use a panic=... timeout and
 			need the box quickly up again.
 
+			These settings can be accessed at runtime via
+			the nmi_watchdog and hardlockup_panic sysctls.
+
 	netpoll.carrier_timeout=
 			[NET] Specifies amount of time (in seconds) that
 			netpoll should wait for a carrier. By default netpoll
Documentation/sysctl/kernel.txt +14 -0
index 694968c7523c..63663039acb7 100644
@@ -34,6 +34,7 @@ show up in /proc/sys/kernel:
 - hostname
 - hotplug
 - hardlockup_all_cpu_backtrace
+- hardlockup_panic
 - hung_task_panic
 - hung_task_check_count
 - hung_task_timeout_secs
@@ -313,6 +314,19 @@ will be initiated.
 1: on detection capture more debug information.
 ==============================================================
 
+hardlockup_panic:
+
+This parameter can be used to control whether the kernel panics
+when a hard lockup is detected.
+
+   0 - don't panic on hard lockup
+   1 - panic on hard lockup
+
+See Documentation/lockup-watchdogs.txt for more information.  This can
+also be set using the nmi_watchdog kernel parameter.
+
+==============================================================
+
 hotplug:
 
 Path for the hotplug policy agent.
Signature · 1 line
2.9.5
#1 lore raw

Ack

Sent from my iPhone

Quoted 62 lines · Scott Wood

Commit ac1f591249d95372f ("kernel/watchdog.c: add sysctl knob hardlockup_panic") added the hardlockup_panic sysctl, but did not add it to Documentation/sysctl/kernel.txt. Add this, and reference it from the corresponding entry in Documentation/admin-guide/kernel-parameters.txt.

---
Documentation/admin-guide/kernel-parameters.txt | 3 +++
Documentation/sysctl/kernel.txt | 14 ++++++++++++++

2 files changed, 17 insertions(+)
Documentation/admin-guide/kernel-parameters.txt +3 -0
index 6571fbfdb2a1..dfb7c35b5826 100644
@@ -2538,6 +2538,9 @@
           This is useful when you use a panic=... timeout and
           need the box quickly up again.
 
+            These settings can be accessed at runtime via
+            the nmi_watchdog and hardlockup_panic sysctls.
+
   netpoll.carrier_timeout=
           [NET] Specifies amount of time (in seconds) that
           netpoll should wait for a carrier. By default netpoll
Documentation/sysctl/kernel.txt +1 -6
index 694968c7523c..63663039acb7 100644
@@ -34,6 +34,7 @@ show up in /proc/sys/kernel:
- hostname
- hotplug
- hardlockup_all_cpu_backtrace
+- hardlockup_panic
- hung_task_panic
- hung_task_check_count
- hung_task_timeout_secs
@@ -313,6 +314,19 @@ will be initiated.

1: on detection capture more debug information.
==============================================================

Documentation/sysctl/kernel.txt +13 -0
+hardlockup_panic:
+
+This parameter can be used to control whether the kernel panics
+when a hard lockup is detected.
+
+   0 - don't panic on hard lockup
+   1 - panic on hard lockup
+
+See Documentation/lockup-watchdogs.txt for more information.  This can
+also be set using the nmi_watchdog kernel parameter.
+
+==============================================================
+

hotplug:

Path for the hotplug policy agent.

Signature · 1 line
2.9.5
Acked-by on v1 1/1
#2 lore raw
In reply to Scott Wood
Quoted 4 lines · Scott Wood

Commit ac1f591249d95372f ("kernel/watchdog.c: add sysctl knob hardlockup_panic") added the hardlockup_panic sysctl, but did not add it to Documentation/sysctl/kernel.txt. Add this, and reference it from the corresponding entry in Documentation/admin-guide/kernel-parameters.txt.

Quoted 56 lines
---
 Documentation/admin-guide/kernel-parameters.txt |  3 +++
 Documentation/sysctl/kernel.txt                 | 14 ++++++++++++++
 2 files changed, 17 insertions(+)
Documentation/admin-guide/kernel-parameters.txt +3 -0
index 6571fbfdb2a1..dfb7c35b5826 100644
@@ -2538,6 +2538,9 @@
 			This is useful when you use a panic=... timeout and
 			need the box quickly up again.
 
+			These settings can be accessed at runtime via
+			the nmi_watchdog and hardlockup_panic sysctls.
+
 	netpoll.carrier_timeout=
 			[NET] Specifies amount of time (in seconds) that
 			netpoll should wait for a carrier. By default netpoll
Documentation/sysctl/kernel.txt +14 -0
index 694968c7523c..63663039acb7 100644
@@ -34,6 +34,7 @@ show up in /proc/sys/kernel:
 - hostname
 - hotplug
 - hardlockup_all_cpu_backtrace
+- hardlockup_panic
 - hung_task_panic
 - hung_task_check_count
 - hung_task_timeout_secs
@@ -313,6 +314,19 @@ will be initiated.
 1: on detection capture more debug information.
 ==============================================================
 
+hardlockup_panic:
+
+This parameter can be used to control whether the kernel panics
+when a hard lockup is detected.
+
+   0 - don't panic on hard lockup
+   1 - panic on hard lockup
+
+See Documentation/lockup-watchdogs.txt for more information.  This can
+also be set using the nmi_watchdog kernel parameter.
+
+==============================================================
+
 hotplug:
 
 Path for the hotplug policy agent.
Signature · 1 line
2.9.5
maintainer Applied
#3 lore raw
In reply to Scott Wood
Quoted 4 lines · On Sun, 10 Dec 2017 01:48:46 -0600 Scott Wood <[email protected]> wrote:

Commit ac1f591249d95372f ("kernel/watchdog.c: add sysctl knob hardlockup_panic") added the hardlockup_panic sysctl, but did not add it to Documentation/sysctl/kernel.txt. Add this, and reference it from the corresponding entry in Documentation/admin-guide/kernel-parameters.txt.

Applied to the docs tree, thanks.

jon