On Thu, 13 Apr 2023 at 15:12, 'Alexander Potapenko' via kasan-dev
<kasan-dev@xxxxxxxxxxxxxxxx> wrote:
>
> Non-void KMSAN hooks may return error codes that indicate that KMSAN
> failed to reflect the changed memory state in the metadata (e.g. it
> could not create the necessary memory mappings). In such cases the
> callers should handle the errors to prevent the tool from using the
> inconsistent metadata in the future.
>
> We mark non-void hooks with __must_check so that error handling is not
> skipped.
>
> Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
> ---
> include/linux/kmsan.h | 43 ++++++++++++++++++++++---------------------
> 1 file changed, 22 insertions(+), 21 deletions(-)
>
> diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h
> index 30b17647ce3c7..e0c23a32cdf01 100644
> --- a/include/linux/kmsan.h
> +++ b/include/linux/kmsan.h
> @@ -54,7 +54,8 @@ void __init kmsan_init_runtime(void);
> * Freed pages are either returned to buddy allocator or held back to be used
> * as metadata pages.
> */
> -bool __init kmsan_memblock_free_pages(struct page *page, unsigned int order);
> +bool __init __must_check kmsan_memblock_free_pages(struct page *page,
> + unsigned int order);
>
> /**
> * kmsan_alloc_page() - Notify KMSAN about an alloc_pages() call.
> @@ -137,9 +138,11 @@ void kmsan_kfree_large(const void *ptr);
> * vmalloc metadata address range. Returns 0 on success, callers must check
> * for non-zero return value.
> */
> -int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end,
> - pgprot_t prot, struct page **pages,
> - unsigned int page_shift);
> +int __must_check kmsan_vmap_pages_range_noflush(unsigned long start,
> + unsigned long end,
> + pgprot_t prot,
> + struct page **pages,
> + unsigned int page_shift);
>
> /**
> * kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap.
> @@ -163,9 +166,9 @@ void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end);
> * virtual memory. Returns 0 on success, callers must check for non-zero return
> * value.
> */
> -int kmsan_ioremap_page_range(unsigned long addr, unsigned long end,
> - phys_addr_t phys_addr, pgprot_t prot,
> - unsigned int page_shift);
> +int __must_check kmsan_ioremap_page_range(unsigned long addr, unsigned long end,
> + phys_addr_t phys_addr, pgprot_t prot,
> + unsigned int page_shift);
>
> /**
> * kmsan_iounmap_page_range() - Notify KMSAN about a iounmap_page_range() call.
> @@ -237,8 +240,8 @@ static inline void kmsan_init_runtime(void)
> {
> }
>
> -static inline bool kmsan_memblock_free_pages(struct page *page,
> - unsigned int order)
> +static inline bool __must_check kmsan_memblock_free_pages(struct page *page,
> + unsigned int order)
> {
> return true;
> }
> @@ -251,10 +254,9 @@ static inline void kmsan_task_exit(struct task_struct *task)
> {
> }
>
> -static inline int kmsan_alloc_page(struct page *page, unsigned int order,
> - gfp_t flags)
> +static inline void kmsan_alloc_page(struct page *page, unsigned int order,
> + gfp_t flags)
> {
> - return 0;
> }
>
> static inline void kmsan_free_page(struct page *page, unsigned int order)
> @@ -283,11 +285,9 @@ static inline void kmsan_kfree_large(const void *ptr)
> {
> }
>
> -static inline int kmsan_vmap_pages_range_noflush(unsigned long start,
> - unsigned long end,
> - pgprot_t prot,
> - struct page **pages,
> - unsigned int page_shift)
> +static inline int __must_check kmsan_vmap_pages_range_noflush(
> + unsigned long start, unsigned long end, pgprot_t prot,
> + struct page **pages, unsigned int page_shift)
> {
> return 0;
> }
> @@ -297,10 +297,11 @@ static inline void kmsan_vunmap_range_noflush(unsigned long start,
> {
> }
>
> -static inline int kmsan_ioremap_page_range(unsigned long start,
> - unsigned long end,
> - phys_addr_t phys_addr, pgprot_t prot,
> - unsigned int page_shift)
> +static inline int __must_check kmsan_ioremap_page_range(unsigned long start,
> + unsigned long end,
> + phys_addr_t phys_addr,
> + pgprot_t prot,
> + unsigned int page_shift)
> {
> return 0;
> }
> --
> 2.40.0.577.gac1e443424-goog
>
> --
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