2024-02-05 09:06:05

by Kees Cook

Subject: [PATCH v2] ubsan: Silence W=1 warnings in self-test

Silence a handful of W=1 warnings in the UBSan selftest, which set
variables without using them. For example:

lib/test_ubsan.c:101:6: warning: variable 'val1' set but not used [-Wunused-but-set-variable]
101 | int val1 = 10;
| ^

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Signed-off-by: Kees Cook <[email protected]>
---
v2:
- add additional "volatile" annotations for potential future proofing (marco)
v1: https://lore.kernel.org/all/[email protected]/
---
lib/Makefile | 1 +
lib/test_ubsan.c | 4 ++--
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index 6b09731d8e61..bc36a5c167db 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o
obj-$(CONFIG_TEST_IDA) += test_ida.o
obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o
CFLAGS_test_ubsan.o += $(call cc-disable-warning, vla)
+CFLAGS_test_ubsan.o += $(call cc-disable-warning, unused-but-set-variable)
UBSAN_SANITIZE_test_ubsan.o := y
obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o
diff --git a/lib/test_ubsan.c b/lib/test_ubsan.c
index 2062be1f2e80..f4ee2484d4b5 100644
--- a/lib/test_ubsan.c
+++ b/lib/test_ubsan.c
@@ -23,8 +23,8 @@ static void test_ubsan_divrem_overflow(void)
static void test_ubsan_shift_out_of_bounds(void)
{
volatile int neg = -1, wrap = 4;
- int val1 = 10;
- int val2 = INT_MAX;
+ volatile int val1 = 10;
+ volatile int val2 = INT_MAX;

UBSAN_TEST(CONFIG_UBSAN_SHIFT, "negative exponent");
val1 <<= neg;
--
2.34.1

2024-02-05 11:09:30

by Marco Elver

Subject: Re: [PATCH v2] ubsan: Silence W=1 warnings in self-test

On Mon, 5 Feb 2024 at 10:03, Kees Cook <[email protected]> wrote:
>
> Silence a handful of W=1 warnings in the UBSan selftest, which set
> variables without using them. For example:
>
> lib/test_ubsan.c:101:6: warning: variable 'val1' set but not used [-Wunused-but-set-variable]
> 101 | int val1 = 10;
> | ^
>
> Reported-by: kernel test robot <[email protected]>
> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Marco Elver <[email protected]>

> ---
> v2:
> - add additional "volatile" annotations for potential future proofing (marco)
> v1: https://lore.kernel.org/all/[email protected]/
> ---
> lib/Makefile | 1 +
> lib/test_ubsan.c | 4 ++--
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/lib/Makefile b/lib/Makefile
> index 6b09731d8e61..bc36a5c167db 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -69,6 +69,7 @@ obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o
> obj-$(CONFIG_TEST_IDA) += test_ida.o
> obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o
> CFLAGS_test_ubsan.o += $(call cc-disable-warning, vla)
> +CFLAGS_test_ubsan.o += $(call cc-disable-warning, unused-but-set-variable)
> UBSAN_SANITIZE_test_ubsan.o := y
> obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
> obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o
> diff --git a/lib/test_ubsan.c b/lib/test_ubsan.c
> index 2062be1f2e80..f4ee2484d4b5 100644
> --- a/lib/test_ubsan.c
> +++ b/lib/test_ubsan.c
> @@ -23,8 +23,8 @@ static void test_ubsan_divrem_overflow(void)
> static void test_ubsan_shift_out_of_bounds(void)
> {
> volatile int neg = -1, wrap = 4;
> - int val1 = 10;
> - int val2 = INT_MAX;
> + volatile int val1 = 10;
> + volatile int val2 = INT_MAX;
>
> UBSAN_TEST(CONFIG_UBSAN_SHIFT, "negative exponent");
> val1 <<= neg;
> --
> 2.34.1
>
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