[PATCH 2/2] memblock: annotate struct memblock_type with __counted_by_ptr

[Bill Wendling <morbo@google.com>]

Add the '__counted_by_ptr' attribute to the 'regions' field of 'struct
memblock_type'. The 'regions' field is an array of 'struct
memblock_region' and its size is tracked by the 'max' field, which
represents the total number of allocated regions.

This annotation allows the Kernel Address Sanitizer (KASAN) to detect
out-of-bounds accesses to the 'regions' array.

Cc: Kees Cook <kees@kernel.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Marc Herbert <Marc.Herbert@linux.intel.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: "Thomas Weißschuh" <thomas.weissschuh@linutronix.de>
Cc: John Stultz <jstultz@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-hardening@vger.kernel.org
Cc: llvm@lists.linux.dev
Signed-off-by: Bill Wendling <morbo@google.com>
---
 include/linux/memblock.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 221118b5a16e..ba7f7c999a45 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -91,7 +91,7 @@ struct memblock_type {
 	unsigned long cnt;
 	unsigned long max;
 	phys_addr_t total_size;
-	struct memblock_region *regions;
+	struct memblock_region *regions __counted_by_ptr(max);
 	char *name;
 };
 
-- 
2.52.0.rc2.455.g230fcf2819-goog