On Wed, Nov 4, 2020 at 2:21 PM Dmitry Osipenko <digetx@xxxxxxxxx> wrote:
>
> Annotate tegra_pm_set[clear]_cpu_in_lp2() with RCU_NONIDLE in order to
> fix lockdep warning about suspicious RCU usage of a spinlock during late
> idling phase.
>
> WARNING: suspicious RCU usage
> ...
> include/trace/events/lock.h:13 suspicious rcu_dereference_check() usage!
> ...
> (dump_stack) from (lock_acquire)
> (lock_acquire) from (_raw_spin_lock)
> (_raw_spin_lock) from (tegra_pm_set_cpu_in_lp2)
> (tegra_pm_set_cpu_in_lp2) from (tegra_cpuidle_enter)
> (tegra_cpuidle_enter) from (cpuidle_enter_state)
> (cpuidle_enter_state) from (cpuidle_enter_state_coupled)
> (cpuidle_enter_state_coupled) from (cpuidle_enter)
> (cpuidle_enter) from (do_idle)
> ...
>
> Tested-by: Peter Geis <pgwipeout@xxxxxxxxx>
> Reported-by: Peter Geis <pgwipeout@xxxxxxxxx>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
> drivers/cpuidle/cpuidle-tegra.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c
> index e8956706a291..191966dc8d02 100644
> --- a/drivers/cpuidle/cpuidle-tegra.c
> +++ b/drivers/cpuidle/cpuidle-tegra.c
> @@ -189,7 +189,7 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
> }
>
> local_fiq_disable();
> - tegra_pm_set_cpu_in_lp2();
> + RCU_NONIDLE(tegra_pm_set_cpu_in_lp2());
> cpu_pm_enter();
>
> switch (index) {
> @@ -207,7 +207,7 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
> }
>
> cpu_pm_exit();
> - tegra_pm_clear_cpu_in_lp2();
> + RCU_NONIDLE(tegra_pm_clear_cpu_in_lp2());
> local_fiq_enable();
>
> return err ?: index;
> --
Applied as a fix for 5.10-rc, thanks!
