[PATCH v5 1/6] kernel/reboot: emergency_restart: set correct system_state

Benjamin Bara
2023-04-18T11:10:47Z

From: Benjamin Bara <benjamin.bara@skidata.com>

As the emergency restart does not call kernel_restart_prepare(), the
system_state stays in SYSTEM_RUNNING.

Since bae1d3a05a8b, this hinders i2c_in_atomic_xfer_mode() from becoming
active, and therefore might lead to avoidable warnings in the restart
handlers, e.g.:

[ 12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0
[ 12.676926] Voluntary context switch within RCU read-side critical section!
...
[ 12.742376] schedule_timeout from wait_for_completion_timeout+0x90/0x114
[ 12.749179] wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70
...
[ 12.994527] atomic_notifier_call_chain from machine_restart+0x34/0x58
[ 13.001050] machine_restart from panic+0x2a8/0x32c

Avoid these by setting the correct system_state.

Fixes: bae1d3a05a8b ("i2c: core: remove use of in_atomic()")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com>
---
kernel/reboot.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3bba88c7ffc6..6ebef11c8876 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -74,6 +74,7 @@ void __weak (*pm_power_off)(void);
void emergency_restart(void)
{
kmsg_dump(KMSG_DUMP_EMERG);
+ system_state = SYSTEM_RESTART;
machine_emergency_restart();
}
EXPORT_SYMBOL_GPL(emergency_restart);

--
2.34.1