On Thu, May 21, 2026 at 07:18:03AM +0000, Dmitry Ilvokhin wrote:
> Add __nonnull() to unconditional guard constructors so the compiler
> warns when NULL is statically known to be passed:
>
> - DEFINE_GUARD(): re-declare the constructor with __nonnull().
> - __DEFINE_LOCK_GUARD_1(): annotate the constructor directly.
>
> DEFINE_LOCK_GUARD_0() needs no annotation: its constructor takes no
> pointer arguments (.lock is hardcoded to (void *)1).
>
> Define the __nonnull() macro in compiler_attributes.h, following the
> existing convention for attribute wrappers.
>
> Signed-off-by: Dmitry Ilvokhin <[email protected]>
> Acked-by: Miguel Ojeda <[email protected]>
The build robot found something to hate in this one. I think you're on
Cc there. It looks to me like clang-23 is confused somehow, but who
knows.
> ---
> include/linux/cleanup.h | 4 +++-
> include/linux/compiler_attributes.h | 6 ++++++
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
> index ea95ca4bc11c..8f8d588b5595 100644
> --- a/include/linux/cleanup.h
> +++ b/include/linux/cleanup.h
> @@ -397,6 +397,7 @@ static __maybe_unused const bool
> class_##_name##_is_conditional = _is_cond
> __DEFINE_GUARD_LOCK_PTR(_name, _T)
>
> #define DEFINE_GUARD(_name, _type, _lock, _unlock) \
> + static __always_inline __nonnull() _type
> class_##_name##_constructor(_type _T); \
> DEFINE_CLASS(_name, _type, if (_T) { _unlock; }, ({ _lock; _T; }),
> _type _T); \
> DEFINE_CLASS_IS_GUARD(_name)
>
> @@ -497,7 +498,8 @@ static __always_inline void
> class_##_name##_destructor(class_##_name##_t *_T) \
> __DEFINE_GUARD_LOCK_PTR(_name, &_T->lock)
>
> #define __DEFINE_LOCK_GUARD_1(_name, _type, ...) \
> -static __always_inline class_##_name##_t class_##_name##_constructor(_type
> *l) \
> +static __always_inline __nonnull() \
> +class_##_name##_t class_##_name##_constructor(_type *l)
> \
> __no_context_analysis \
> { \
> class_##_name##_t _t = { .lock = l }, *_T = &_t; \
> diff --git a/include/linux/compiler_attributes.h
> b/include/linux/compiler_attributes.h
> index c16d4199bf92..10a1410eb3e2 100644
> --- a/include/linux/compiler_attributes.h
> +++ b/include/linux/compiler_attributes.h
> @@ -230,6 +230,12 @@
> */
> #define noinline __attribute__((__noinline__))
>
> +/*
> + * gcc:
> https://gcc.gnu.org/onlinedocs/gcc/Common-Attributes.html#index-nonnull
> + * clang: https://clang.llvm.org/docs/AttributeReference.html#nonnull
> + */
> +#define __nonnull(x...) __attribute__((__nonnull__(x)))
> +
> /*
> * Optional: only supported since gcc >= 8
> * Optional: not supported by clang
> --
> 2.53.0-Meta
>
