2022-11-09 08:43:56

by Zqiang

Subject: [PATCH] srcu: Make Tiny SRCU synchronize_srcu() more complete

This commit add lockdep detection for illegal use synchronize_srcu()
in same-type SRCU (or in RCU) read-side critical section and support
early boot operations.

Signed-off-by: Zqiang <[email protected]>
---
kernel/rcu/srcutiny.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 33adafdad261..b12fb0cec44d 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -197,6 +197,16 @@ void synchronize_srcu(struct srcu_struct *ssp)
{
struct rcu_synchronize rs;

+ RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||
+ lock_is_held(&rcu_bh_lock_map) ||
+ lock_is_held(&rcu_lock_map) ||
+ lock_is_held(&rcu_sched_lock_map),
+ "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");
+
+ if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
+ return;
+
+ might_sleep();
init_rcu_head_on_stack(&rs.head);
init_completion(&rs.completion);
call_srcu(ssp, &rs.head, wakeme_after_rcu);
--
2.25.1

2022-11-11 08:27:00

by Paul E. McKenney

Subject: Re: [PATCH] srcu: Make Tiny SRCU synchronize_srcu() more complete

On Wed, Nov 09, 2022 at 03:36:38PM +0800, Zqiang wrote:
> This commit add lockdep detection for illegal use synchronize_srcu()
> in same-type SRCU (or in RCU) read-side critical section and support
> early boot operations.
>
> Signed-off-by: Zqiang <[email protected]>

Queued and pushed with the usual wordsmithing (please check), thank you!

Thanx, Paul

> ---
> kernel/rcu/srcutiny.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
> index 33adafdad261..b12fb0cec44d 100644
> --- a/kernel/rcu/srcutiny.c
> +++ b/kernel/rcu/srcutiny.c
> @@ -197,6 +197,16 @@ void synchronize_srcu(struct srcu_struct *ssp)
> {
> struct rcu_synchronize rs;
>
> + RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||
> + lock_is_held(&rcu_bh_lock_map) ||
> + lock_is_held(&rcu_lock_map) ||
> + lock_is_held(&rcu_sched_lock_map),
> + "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");
> +
> + if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
> + return;
> +
> + might_sleep();
> init_rcu_head_on_stack(&rs.head);
> init_completion(&rs.completion);
> call_srcu(ssp, &rs.head, wakeme_after_rcu);
> --
> 2.25.1
>

2022-11-11 11:37:29

by Zqiang

Subject: RE: [PATCH] srcu: Make Tiny SRCU synchronize_srcu() more complete

On Wed, Nov 09, 2022 at 03:36:38PM +0800, Zqiang wrote:
> This commit add lockdep detection for illegal use synchronize_srcu()
> in same-type SRCU (or in RCU) read-side critical section and support
> early boot operations.
>
> Signed-off-by: Zqiang <[email protected]>
>
>Queued and pushed with the usual wordsmithing (please check), thank you!

Thanks for wordsmithing, I have seen the new commit message ????.

>
> Thanx, Paul
>
> ---
> kernel/rcu/srcutiny.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
> index 33adafdad261..b12fb0cec44d 100644
> --- a/kernel/rcu/srcutiny.c
> +++ b/kernel/rcu/srcutiny.c
> @@ -197,6 +197,16 @@ void synchronize_srcu(struct srcu_struct *ssp)
> {
> struct rcu_synchronize rs;
>
> + RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||
> + lock_is_held(&rcu_bh_lock_map) ||
> + lock_is_held(&rcu_lock_map) ||
> + lock_is_held(&rcu_sched_lock_map),
> + "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");
> +
> + if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
> + return;
> +
> + might_sleep();
> init_rcu_head_on_stack(&rs.head);
> init_completion(&rs.completion);
> call_srcu(ssp, &rs.head, wakeme_after_rcu);
> --
> 2.25.1
>