5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Benjamin Bara <benjamin.bara@xxxxxxxxxxx>
commit 60466c067927abbcaff299845abd4b7069963139 upstream.
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@xxxxxxxxxxxxxxx # v5.2+
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Tested-by: Nishanth Menon <nm@xxxxxx>
Signed-off-by: Benjamin Bara <benjamin.bara@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-1-18699d5dcd76@xxxxxxxxxxx
Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/reboot.c | 1 +
1 file changed, 1 insertion(+)
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -64,6 +64,7 @@ EXPORT_SYMBOL_GPL(pm_power_off_prepare);
void emergency_restart(void)
{
kmsg_dump(KMSG_DUMP_EMERG);
+ system_state = SYSTEM_RESTART;
machine_emergency_restart();
}
EXPORT_SYMBOL_GPL(emergency_restart);
