Re: [PATCH 16/17] rcu: assert static storage for RCU sync and SRCU definitions

[Joel Fernandes]

On Mon, Sep 14, 2026 at 11:13:31PM -0400, Yury Norov wrote:
> DEFINE_RCU_SYNC() contains a statically initialized wait queue. SRCU
> static definitions similarly rely on persistent lockdep keys and, in
> Tiny SRCU, a statically initialized work item.
> 
> Add ASSERT_STATIC_STORAGE() to DEFINE_RCU_SYNC(), both Tree SRCU
> __DEFINE_SRCU() variants and Tiny SRCU's common DEFINE_SRCU() declaration.
> This covers the non-static FAST and FAST_UPDOWN wrappers too. Tiny SRCU's
> explicitly static declarations already enforce the required duration.
> The existing per-CPU restrictions on Tree SRCU declarations still apply.
> 
> Assisted-by: OpenAI Codex
> Signed-off-by: Yury Norov <ynorov@xxxxxxxxxx>

All the changes make sense to me. I'm ok with carrying this for -rcu 7.5
unless you want to take it.

Reviewed-by: Joel Fernandes <joelagnelf@xxxxxxxxxx>

thanks,

Joel Fernandes


> ---
>  include/linux/rcu_sync.h | 4 +++-
>  include/linux/srcutiny.h | 4 +++-
>  include/linux/srcutree.h | 7 +++++--
>  3 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/rcu_sync.h b/include/linux/rcu_sync.h
> index 3860dbb9107a..c10b6d30561a 100644
> --- a/include/linux/rcu_sync.h
> +++ b/include/linux/rcu_sync.h
> @@ -10,6 +10,7 @@
>  #ifndef _LINUX_RCU_SYNC_H_
>  #define _LINUX_RCU_SYNC_H_
>  
> +#include <linux/compiler.h>
>  #include <linux/wait.h>
>  #include <linux/rcupdate.h>
>  
> @@ -48,6 +49,7 @@ extern void rcu_sync_dtor(struct rcu_sync *);
>  	}
>  
>  #define	DEFINE_RCU_SYNC(name)	\
> -	struct rcu_sync name = __RCU_SYNC_INITIALIZER(name)
> +	struct rcu_sync name = __RCU_SYNC_INITIALIZER(name);	\
> +	ASSERT_STATIC_STORAGE(name)
>  
>  #endif /* _LINUX_RCU_SYNC_H_ */
> diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h
> index fbcf13bc12d1..40b592b4e2d8 100644
> --- a/include/linux/srcutiny.h
> +++ b/include/linux/srcutiny.h
> @@ -11,6 +11,7 @@
>  #ifndef _LINUX_SRCU_TINY_H
>  #define _LINUX_SRCU_TINY_H
>  
> +#include <linux/compiler.h>
>  #include <linux/irq_work_types.h>
>  #include <linux/swait.h>
>  
> @@ -48,7 +49,8 @@ void srcu_tiny_irq_work(struct irq_work *irq_work);
>   * Tree SRCU, which needs some per-CPU data.
>   */
>  #define DEFINE_SRCU(name) \
> -	struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name, name)
> +	struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name, name);	\
> +	ASSERT_STATIC_STORAGE(name)
>  #define DEFINE_STATIC_SRCU(name) \
>  	static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name, name)
>  #define DEFINE_SRCU_FAST(name) DEFINE_SRCU(name)
> diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
> index 75e54e4f963f..8bea8044230a 100644
> --- a/include/linux/srcutree.h
> +++ b/include/linux/srcutree.h
> @@ -11,6 +11,7 @@
>  #ifndef _LINUX_SRCU_TREE_H
>  #define _LINUX_SRCU_TREE_H
>  
> +#include <linux/compiler.h>
>  #include <linux/rcu_node_tree.h>
>  #include <linux/completion.h>
>  
> @@ -217,13 +218,15 @@ struct srcu_struct {
>  								      fast);			\
>  	extern struct srcu_struct * const __srcu_struct_##name;					\
>  	struct srcu_struct * const __srcu_struct_##name						\
> -		__section("___srcu_struct_ptrs") = &name
> +		__section("___srcu_struct_ptrs") = &name;					\
> +	ASSERT_STATIC_STORAGE(name)
>  #else
>  # define __DEFINE_SRCU(name, fast, is_static)							\
>  	static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);				\
>  	static struct srcu_usage name##_srcu_usage = __SRCU_USAGE_INIT(name##_srcu_usage);	\
>  	is_static struct srcu_struct name =							\
> -		__SRCU_STRUCT_INIT(name, name##_srcu_usage, name##_srcu_data, fast)
> +		__SRCU_STRUCT_INIT(name, name##_srcu_usage, name##_srcu_data, fast);		\
> +	ASSERT_STATIC_STORAGE(name)
>  #endif
>  #define DEFINE_SRCU(name)		__DEFINE_SRCU(name, 0, /* not static */)
>  #define DEFINE_STATIC_SRCU(name)	__DEFINE_SRCU(name, 0, static)
> -- 
> 2.53.0
>