[039/262] percpu: add __alloc_size attributes for better bounds checking

Commit Message

Andrew Morton Nov. 5, 2021, 8:36 p.m. UTC

From: Kees Cook <[e-mail]>
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/[e-mail]
Signed-off-by: Kees Cook <[e-mail]>
Co-developed-by: Daniel Micay <[e-mail]>
Signed-off-by: Daniel Micay <[e-mail]>
Acked-by: Dennis Zhou <[e-mail]>
Cc: Tejun Heo <[e-mail]>
Cc: Christoph Lameter <[e-mail]>
Cc: Andy Whitcroft <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Dwaipayan Ray <[e-mail]>
Cc: Joe Perches <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Lukas Bulwahn <[e-mail]>
Cc: Miguel Ojeda <[e-mail]>
Cc: Nathan Chancellor <[e-mail]>
Cc: Nick Desaulniers <[e-mail]>
Cc: Pekka Enberg <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Alexandre Bounine <[e-mail]>
Cc: Gustavo A. R. Silva <[e-mail]>
Cc: Ira Weiny <[e-mail]>
Cc: Jing Xiangfeng <[e-mail]>
Cc: John Hubbard <[e-mail]>
Cc: kernel test robot <[e-mail]>
Cc: Matt Porter <[e-mail]>
Cc: Randy Dunlap <[e-mail]>
Cc: Souptick Joarder <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/percpu.h |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Patch

--- 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);