# Re: \[PATCH 01/17\] locking/mutex: assert static storage for DEFINE\_MUTEX()

- From: Peter Zijlstra \<peterz@infradead.org\>
- Date: 2026-09-15 08:23:18 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2026/09/17577998
- Thread: https://ratatoskr.run/linuxppc-dev/2026/09/17576885/t.md

```text
On Mon, Sep 14, 2026 at 11:03:19PM -0400, Yury Norov wrote:
> DEFINE_MUTEX() uses a static lock initializer whose lockdep class key
> requires a persistent object address. Reject automatic local declarations
> with ASSERT_STATIC_STORAGE(), in both the regular and PREEMPT_RT variants.
> Align the VMA and memblock tools stubs with the kernel declaration.
> 
> The two automatic mutexes in the WireGuard allowedips selftests already
> call mutex_init(). Replace their redundant static initializers with plain
> struct mutex declarations.
> 
> Assisted-by: OpenAI Codex
> Signed-off-by: Yury Norov <redacted>
> ---
>  drivers/net/wireguard/selftest/allowedips.c | 4 ++--
>  include/linux/mutex.h                       | 7 +++++--
>  tools/testing/memblock/linux/mutex.h        | 8 ++++++--
>  tools/testing/vma/include/dup.h             | 5 ++++-
>  4 files changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/wireguard/selftest/allowedips.c b/drivers/net/wireguard/selftest/allowedips.c
> index 3e857e6fb627..ecb2908228e7 100644
> --- a/drivers/net/wireguard/selftest/allowedips.c
> +++ b/drivers/net/wireguard/selftest/allowedips.c
> @@ -257,7 +257,7 @@ static __init bool randomized_test(void)
>  	u8 ip[16], mutate_mask[16], mutated[16];
>  	struct wg_peer **peers, *peer;
>  	struct horrible_allowedips h;
> -	DEFINE_MUTEX(mutex);
> +	struct mutex mutex;
>  	struct allowedips t;
>  	bool ret = false;
>  
> @@ -499,7 +499,7 @@ bool __init wg_allowedips_selftest(void)
>  	struct allowedips_node *iter_node;
>  	bool success = false;
>  	struct allowedips t;
> -	DEFINE_MUTEX(mutex);
> +	struct mutex mutex;
>  	struct in6_addr ip;
>  	size_t i = 0, count = 0;
>  	__be64 part;

This should probably be a separate patch.

> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
> index 734048c02f4f..2f2d95f3097c 100644
> --- a/include/linux/mutex.h
> +++ b/include/linux/mutex.h
> @@ -11,6 +11,7 @@
>  #ifndef __LINUX_MUTEX_H
>  #define __LINUX_MUTEX_H
>  
> +#include <linux/compiler.h>
>  #include <asm/current.h>
>  #include <linux/list.h>
>  #include <linux/spinlock_types.h>
> @@ -84,7 +85,8 @@ do {									\
>  		__DEP_MAP_MUTEX_INITIALIZER(lockname) }
>  
>  #define DEFINE_MUTEX(mutexname) \
> -	struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
> +	struct mutex mutexname = __MUTEX_INITIALIZER(mutexname);	\
> +	ASSERT_STATIC_STORAGE(mutexname)

My tree no has ASSERT_STATIC_STORAGE. Please repost when that lands?

```