5.4-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Bara benjamin.bara@skidata.com
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@vger.kernel.org # v5.2+ Reviewed-by: Dmitry Osipenko dmitry.osipenko@collabora.com Tested-by: Nishanth Menon nm@ti.com Signed-off-by: Benjamin Bara benjamin.bara@skidata.com Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-1-18699d5dcd76@skida... Signed-off-by: Lee Jones lee@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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);