The patch titled Subject: kasan/test: avoid gcc warning for intentional overflow has been added to the -mm mm-unstable branch. Its filename is kasan-test-avoid-gcc-warning-for-intentional-overflow.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Arnd Bergmann arnd@arndb.de Subject: kasan/test: avoid gcc warning for intentional overflow Date: Mon, 12 Feb 2024 12:15:52 +0100
The out-of-bounds test allocates an object that is three bytes too short in order to validate the bounds checking. Starting with gcc-14, this causes a compile-time warning as gcc has grown smart enough to understand the sizeof() logic:
mm/kasan/kasan_test.c: In function 'kmalloc_oob_16': mm/kasan/kasan_test.c:443:14: error: allocation of insufficient size '13' for type 'struct <anonymous>' with size '16' [-Werror=alloc-size] 443 | ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL); | ^
Hide the actual computation behind a RELOC_HIDE() that ensures the compiler misses the intentional bug.
Link: https://lkml.kernel.org/r/20240212111609.869266-1-arnd@kernel.org Fixes: 3f15801cdc23 ("lib: add kasan test module") Signed-off-by: Arnd Bergmann arnd@arndb.de Cc: Alexander Potapenko glider@google.com Cc: Andrey Konovalov andreyknvl@gmail.com Cc: Andrey Ryabinin ryabinin.a.a@gmail.com Cc: Arnd Bergmann arnd@arndb.de Cc: Dmitry Vyukov dvyukov@google.com Cc: Marco Elver elver@google.com Cc: Vincenzo Frascino vincenzo.frascino@arm.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/kasan/kasan_test.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/kasan/kasan_test.c~kasan-test-avoid-gcc-warning-for-intentional-overflow +++ a/mm/kasan/kasan_test.c @@ -440,7 +440,8 @@ static void kmalloc_oob_16(struct kunit /* This test is specifically crafted for the generic mode. */ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
- ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL); + /* RELOC_HIDE to prevent gcc from warning about short alloc */ + ptr1 = RELOC_HIDE(kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL), 0); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL); _
Patches currently in -mm which might be from arnd@arndb.de are
mm-damon-dbgfs-implement-deprecation-notice-file-fix.patch kasan-test-avoid-gcc-warning-for-intentional-overflow.patch