[patch 8/9] percpu: add __alloc_size attributes for better bounds checking

From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, apw@canonical.com, cl@linux.com,
	danielmicay@gmail.com, dennis@kernel.org,
	dwaipayanray1@gmail.com, iamjoonsoo.kim@lge.com, joe@perches.com,
	keescook@chromium.org, linux-mm@kvack.org,
	lukas.bulwahn@gmail.com, mm-commits@vger.kernel.org,
	nathan@kernel.org, ndesaulniers@google.com, ojeda@kernel.org,
	penberg@kernel.org, rientjes@google.com, tj@kernel.org,
	torvalds@linux-foundation.org, vbabka@suse.cz
Subject: [patch 8/9] percpu: add __alloc_size attributes for better bounds checking
Date: Thu, 09 Sep 2021 20:10:43 -0700	[thread overview]
Message-ID: <20210910031043.GNMLvLlZC%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210909200948.090d4e213ca34b5ad1325a7e@linux-foundation.org>

From: Kees Cook <keescook@chromium.org>
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.

Link: https://lkml.kernel.org/r/20210818214021.2476230-7-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/include/linux/percpu.h~percpu-add-__alloc_size-attributes-for-better-bounds-checking
+++ a/include/linux/percpu.h
@@ -123,6 +123,7 @@ extern int __init pcpu_page_first_chunk(
 				pcpu_fc_populate_pte_fn_t populate_pte_fn);
 #endif
 
+__alloc_size(1)
 extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
 extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
 extern bool is_kernel_percpu_address(unsigned long addr);
@@ -131,7 +132,9 @@ extern bool is_kernel_percpu_address(uns
 extern void __init setup_per_cpu_areas(void);
 #endif
 
+__alloc_size(1)
 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);
 extern void free_percpu(void __percpu *__pdata);
 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
_
