The patch titled
Subject: reboot: reboot, not shutdown, on hw_protection_reboot timeout
has been added to the -mm mm-nonmm-unstable branch. Its filename is
reboot-reboot-not-shutdown-on-hw_protection_reboot-timeout.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/reboot-reboot-not-shutdown-on-hw_protection_reboot-timeout.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
Subject: reboot: reboot, not shutdown, on hw_protection_reboot timeout
Date: Mon, 17 Feb 2025 21:39:42 +0100
hw_protection_shutdown() will kick off an orderly shutdown and if that
takes longer than a configurable amount of time, an emergency shutdown
will occur.
Recently, hw_protection_reboot() was added for those systems that don't
implement a proper shutdown and are better served by rebooting and having
the boot firmware worry about doing something about the critical
condition.
On timeout of the orderly reboot of hw_protection_reboot(), the system
would go into shutdown, instead of reboot. This is not a good idea, as
going into shutdown was explicitly not asked for.
Fix this by always doing an emergency reboot if hw_protection_reboot() is
called and the orderly reboot takes too long.
Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-2-e1c09b090c0c@xxxxxxxxxxxxxx
Fixes: 79fa723ba84c ("reboot: Introduce thermal_zone_device_critical_reboot()")
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
Reviewed-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
Reviewed-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
Cc: Benson Leung <bleung@xxxxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Fabio Estevam <festevam@xxxxxxx>
Cc: Guenter Roeck <groeck@xxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
Cc: Lukasz Luba <lukasz.luba@xxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Matteo Croce <teknoraver@xxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Rob Herring (Arm) <robh@xxxxxxxxxx>
Cc: Rui Zhang <rui.zhang@xxxxxxxxx>
Cc: Sascha Hauer <kernel@xxxxxxxxxxxxxx>
Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/reboot.c | 70 ++++++++++++++++++++++++++++++++--------------
1 file changed, 49 insertions(+), 21 deletions(-)
--- a/kernel/reboot.c~reboot-reboot-not-shutdown-on-hw_protection_reboot-timeout
+++ a/kernel/reboot.c
@@ -932,48 +932,76 @@ void orderly_reboot(void)
}
EXPORT_SYMBOL_GPL(orderly_reboot);
+static const char *hw_protection_action_str(enum hw_protection_action action)
+{
+ switch (action) {
+ case HWPROT_ACT_SHUTDOWN:
+ return "shutdown";
+ case HWPROT_ACT_REBOOT:
+ return "reboot";
+ default:
+ return "undefined";
+ }
+}
+
+static enum hw_protection_action hw_failure_emergency_action;
+
/**
- * hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay
- * @work: work_struct associated with the emergency poweroff function
+ * hw_failure_emergency_action_func - emergency action work after a known delay
+ * @work: work_struct associated with the emergency action function
*
* This function is called in very critical situations to force
- * a kernel poweroff after a configurable timeout value.
+ * a kernel poweroff or reboot after a configurable timeout value.
*/
-static void hw_failure_emergency_poweroff_func(struct work_struct *work)
+static void hw_failure_emergency_action_func(struct work_struct *work)
{
+ const char *action_str = hw_protection_action_str(hw_failure_emergency_action);
+
+ pr_emerg("Hardware protection timed-out. Trying forced %s\n",
+ action_str);
+
/*
- * We have reached here after the emergency shutdown waiting period has
- * expired. This means orderly_poweroff has not been able to shut off
- * the system for some reason.
+ * We have reached here after the emergency action waiting period has
+ * expired. This means orderly_poweroff/reboot has not been able to
+ * shut off the system for some reason.
*
- * Try to shut down the system immediately using kernel_power_off
- * if populated
+ * Try to shut off the system immediately if possible
*/
- pr_emerg("Hardware protection timed-out. Trying forced poweroff\n");
- kernel_power_off();
+
+ if (hw_failure_emergency_action == HWPROT_ACT_REBOOT)
+ kernel_restart(NULL);
+ else
+ kernel_power_off();
/*
* Worst of the worst case trigger emergency restart
*/
- pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
+ pr_emerg("Hardware protection %s failed. Trying emergency restart\n",
+ action_str);
emergency_restart();
}
-static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
- hw_failure_emergency_poweroff_func);
+static DECLARE_DELAYED_WORK(hw_failure_emergency_action_work,
+ hw_failure_emergency_action_func);
/**
- * hw_failure_emergency_poweroff - Trigger an emergency system poweroff
+ * hw_failure_emergency_schedule - Schedule an emergency system shutdown or reboot
+ *
+ * @action: The hardware protection action to be taken
+ * @action_delay_ms: Time in milliseconds to elapse before triggering action
*
* This may be called from any critical situation to trigger a system shutdown
- * after a given period of time. If time is negative this is not scheduled.
+ * or reboot after a given period of time.
+ * If time is negative this is not scheduled.
*/
-static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
+static void hw_failure_emergency_schedule(enum hw_protection_action action,
+ int action_delay_ms)
{
- if (poweroff_delay_ms <= 0)
+ if (action_delay_ms <= 0)
return;
- schedule_delayed_work(&hw_failure_emergency_poweroff_work,
- msecs_to_jiffies(poweroff_delay_ms));
+ hw_failure_emergency_action = action;
+ schedule_delayed_work(&hw_failure_emergency_action_work,
+ msecs_to_jiffies(action_delay_ms));
}
/**
@@ -1006,7 +1034,7 @@ void __hw_protection_shutdown(const char
* Queue a backup emergency shutdown in the event of
* orderly_poweroff failure
*/
- hw_failure_emergency_poweroff(ms_until_forced);
+ hw_failure_emergency_schedule(action, ms_until_forced);
if (action == HWPROT_ACT_REBOOT)
orderly_reboot();
else
_
Patches currently in -mm which might be from a.fatoum@xxxxxxxxxxxxxx are
reboot-replace-__hw_protection_shutdown-bool-action-parameter-with-an-enum.patch
reboot-reboot-not-shutdown-on-hw_protection_reboot-timeout.patch
docs-thermal-sync-hardware-protection-doc-with-code.patch
reboot-describe-do_kernel_restarts-cmd-argument-in-kernel-doc.patch
reboot-rename-now-misleading-__hw_protection_shutdown-symbols.patch
reboot-indicate-whether-it-is-a-hardware-protection-reboot-or-shutdown.patch
reboot-add-support-for-configuring-emergency-hardware-protection-action.patch
regulator-allow-user-configuration-of-hardware-protection-action.patch
platform-chrome-cros_ec_lpc-prepare-for-hw_protection_shutdown-removal.patch
dt-bindings-thermal-give-os-some-leeway-in-absence-of-critical-action.patch
thermal-core-allow-user-configuration-of-hardware-protection-action.patch
reboot-retire-hw_protection_reboot-and-hw_protection_shutdown-helpers.patch
