On Sat, Sep 12, 2026 at 12:09:13AM +0800, Kunwu Chan wrote:
> Add the RCU_LOCKDEP_WARN and early-boot check that the Tree version
> gained, srcu_lock_sync() was already present.
>
> Suggested-by: Zqiang <[email protected]>
> Signed-off-by: Kunwu Chan <[email protected]>
Queued for testing and review, thank you both!
Thanx, Paul
> ---
> kernel/rcu/srcutiny.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
> index 99f8bfd98b04..76411562366f 100644
> --- a/kernel/rcu/srcutiny.c
> +++ b/kernel/rcu/srcutiny.c
> @@ -361,6 +361,12 @@ void synchronize_srcu_atomic(struct srcu_struct *ssp)
>
> srcu_lock_sync(&ssp->dep_map);
>
> + RCU_LOCKDEP_WARN(lockdep_is_held(ssp),
> + "Illegal synchronize_srcu_atomic() in same-type SRCU
> read-side critical section");
> +
> + if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
> + return;
> +
> if (IS_ENABLED(CONFIG_PREEMPTION))
> synchronize_rcu(); // Needed for RCU Tasks Trace to imply RCU
> grace period.
> // And in Tiny RCU, it is near zero cost and
> doesn't block.
> --
> 2.43.0
>
