The device shutdown callbacks invoked during shutdown/reboot
are prone to errors depending on the device state or mishandling
by one or more driver. In order to prevent a device hang in such
scenarios, we bail out after a timeout while dumping a meaningful
call trace of the shutdown callback which blocks the shutdown or
reboot process.
Change-Id: Ibfc63ca8f8aa45866cbe6b90401d438d95eca742
Signed-off-by: Soumya Khasnis <[email protected]>
Signed-off-by: Srinavasa Nagaraju <[email protected]>
---
drivers/base/Kconfig | 15 +++++++++++++++
kernel/reboot.c | 46 +++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 60 insertions(+), 1 deletion(-)
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 2b8fd6bb7da0..d06e379b6281 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -243,3 +243,18 @@ config FW_DEVLINK_SYNC_STATE_TIMEOUT
work on.
endmenu
+
+config DEVICE_SHUTDOWN_TIMEOUT
+ bool "device shutdown timeout"
+ default n
+ help
+ Enable timeout for device shutdown. Helps in case device shutdown
+ is hung during shoutdonw and reboot.
+
+
+config DEVICE_SHUTDOWN_TIMEOUT_SEC
+ int "device shutdown timeout in seconds"
+ default 5
+ depends on DEVICE_SHUTDOWN_TIMEOUT
+ help
+ sets time for device shutdown timeout in seconds
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 22c16e2564cc..8460bd24563b 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -18,7 +18,7 @@
#include <linux/syscalls.h>
#include <linux/syscore_ops.h>
#include <linux/uaccess.h>
-
+#include <linux/sched/debug.h>
/*
* this indicates whether you can reboot with ctrl-alt-del: the default is yes
*/
@@ -48,6 +48,14 @@ int reboot_cpu;
enum reboot_type reboot_type = BOOT_ACPI;
int reboot_force;
+#ifdef CONFIG_DEVICE_SHUTDOWN_TIMEOUT
+struct device_shutdown_timeout {
+ struct timer_list timer;
+ struct task_struct *task;
+} devs_shutdown;
+#define SHUTDOWN_TIMEOUT CONFIG_DEVICE_SHUTDOWN_TIMEOUT_SEC
+#endif
+
struct sys_off_handler {
struct notifier_block nb;
int (*sys_off_cb)(struct sys_off_data *data);
@@ -88,12 +96,46 @@ void emergency_restart(void)
}
EXPORT_SYMBOL_GPL(emergency_restart);
+#ifdef CONFIG_DEVICE_SHUTDOWN_TIMEOUT
+static void device_shutdown_timeout_handler(struct timer_list *t)
+{
+ pr_emerg("**** device shutdown timeout ****\n");
+ show_stack(devs_shutdown.task, NULL, KERN_EMERG);
+ if (system_state == SYSTEM_RESTART)
+ emergency_restart();
+ else
+ machine_power_off();
+}
+
+static void device_shutdown_timer_set(void)
+{
+ devs_shutdown.task = current;
+ timer_setup(&devs_shutdown.timer, device_shutdown_timeout_handler, 0);
+ devs_shutdown.timer.expires = jiffies + SHUTDOWN_TIMEOUT * HZ;
+ add_timer(&devs_shutdown.timer);
+}
+
+static void device_shutdown_timer_clr(void)
+{
+ del_timer(&devs_shutdown.timer);
+}
+#else
+static inline void device_shutdown_timer_set(void)
+{
+}
+static inline void device_shutdown_timer_clr(void)
+{
+}
+#endif
+
void kernel_restart_prepare(char *cmd)
{
blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
system_state = SYSTEM_RESTART;
usermodehelper_disable();
+ device_shutdown_timer_set();
device_shutdown();
+ device_shutdown_timer_clr();
}
/**
@@ -293,7 +335,9 @@ static void kernel_shutdown_prepare(enum system_states state)
(state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
system_state = state;
usermodehelper_disable();
+ device_shutdown_timer_set();
device_shutdown();
+ device_shutdown_timer_clr();
}
/**
* kernel_halt - halt the system
--
2.40.0
On Wed, May 29, 2024 at 08:32:24AM +0000, Soumya Khasnis wrote:
> The device shutdown callbacks invoked during shutdown/reboot
> are prone to errors depending on the device state or mishandling
> by one or more driver. In order to prevent a device hang in such
> scenarios, we bail out after a timeout while dumping a meaningful
> call trace of the shutdown callback which blocks the shutdown or
> reboot process.
>
> Change-Id: Ibfc63ca8f8aa45866cbe6b90401d438d95eca742
Any reason you didn't run this through checkpatch.pl first?
:(