From: Kees Cook <keescook@xxxxxxxxxxxx> Subject: percpu: add __alloc_size attributes for better bounds checking As already done in GrapheneOS, add the __alloc_size attribute for appropriate percpu allocator interfaces, to provide additional hinting for better bounds checking, assisting CONFIG_FORTIFY_SOURCE and other compiler optimizations. Note that due to the implementation of the percpu API, this is unlikely to ever actually provide compile-time checking beyond very simple non-SMP builds. But, since they are technically allocators, mark them as such. Link: https://lkml.kernel.org/r/20210930222704.2631604-9-keescook@xxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Co-developed-by: Daniel Micay <danielmicay@xxxxxxxxx> Signed-off-by: Daniel Micay <danielmicay@xxxxxxxxx> Acked-by: Dennis Zhou <dennis@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Dwaipayan Ray <dwaipayanray1@xxxxxxxxx> Cc: Joe Perches <joe@xxxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx> Cc: Miguel Ojeda <ojeda@xxxxxxxxxx> Cc: Nathan Chancellor <nathan@xxxxxxxxxx> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Alexandre Bounine <alex.bou9@xxxxxxxxx> Cc: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> Cc: Ira Weiny <ira.weiny@xxxxxxxxx> Cc: Jing Xiangfeng <jingxiangfeng@xxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: kernel test robot <lkp@xxxxxxxxx> Cc: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/percpu.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/include/linux/percpu.h~percpu-add-__alloc_size-attributes-for-better-bounds-checking +++ a/include/linux/percpu.h @@ -123,7 +123,7 @@ extern int __init pcpu_page_first_chunk( pcpu_fc_populate_pte_fn_t populate_pte_fn); #endif -extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align); +extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1); extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr); extern bool is_kernel_percpu_address(unsigned long addr); @@ -131,8 +131,8 @@ extern bool is_kernel_percpu_address(uns extern void __init setup_per_cpu_areas(void); #endif -extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp); -extern void __percpu *__alloc_percpu(size_t size, size_t align); +extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) __alloc_size(1); +extern void __percpu *__alloc_percpu(size_t size, size_t align) __alloc_size(1); extern void free_percpu(void __percpu *__pdata); extern phys_addr_t per_cpu_ptr_to_phys(void *addr); _
