On 21:02-20230509, Benjamin Bara wrote:
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
Tested-by: Nishanth Menon nm@ti.com
This in addition to a deeper bug in our driver seems to have helped resolve a report we had been looking at. Tested on beagleplay platform
https://lore.kernel.org/all/ZGeHMjlnob2GFyHF@francesco-nb.int.toradex.com/