Re: [PATCH] mm:kasan: fix sparse warnings: Should it be static?

[Dmitry Vyukov]

On Fri, 11 Oct 2024 at 05:40, Nihar Chaithanya
<niharchaithanya@xxxxxxxxx> wrote:
>
> The kernel test robot had found sparse warnings: Should it be static,
> for the variables kasan_ptr_result and kasan_int_result. These were
> declared globally and three functions in kasan_test_c.c use them currently.
> Add them to be declared within these functions and remove the global
> versions of these.
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202312261010.o0lRiI9b-lkp@xxxxxxxxx/
> Signed-off-by: Nihar Chaithanya <niharchaithanya@xxxxxxxxx>
> ---
>  mm/kasan/kasan_test_c.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
> index a181e4780d9d..d0d3a9eea80b 100644
> --- a/mm/kasan/kasan_test_c.c
> +++ b/mm/kasan/kasan_test_c.c
> @@ -41,13 +41,6 @@ static struct {
>         bool async_fault;
>  } test_status;
>
> -/*
> - * Some tests use these global variables to store return values from function
> - * calls that could otherwise be eliminated by the compiler as dead code.

Doesn't this change break what's described in this comment?
Since we are assigning to a local var, I assume the compiler can
remove these assignments.

> - */
> -void *kasan_ptr_result;
> -int kasan_int_result;
> -
>  /* Probe for console output: obtains test_status lines of interest. */
>  static void probe_console(void *ignore, const char *buf, size_t len)
>  {
> @@ -1488,6 +1481,7 @@ static void kasan_memchr(struct kunit *test)
>  {
>         char *ptr;
>         size_t size = 24;
> +       void *kasan_ptr_result;
>
>         /*
>          * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
> @@ -1514,6 +1508,7 @@ static void kasan_memcmp(struct kunit *test)
>         char *ptr;
>         size_t size = 24;
>         int arr[9];
> +       int kasan_int_result;
>
>         /*
>          * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
> @@ -1539,6 +1534,8 @@ static void kasan_strings(struct kunit *test)
>  {
>         char *ptr;
>         size_t size = 24;
> +       void *kasan_ptr_result;
> +       int kasan_int_result;
>
>         /*
>          * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
> @@ -1585,6 +1582,8 @@ static void kasan_bitops_modify(struct kunit *test, int nr, void *addr)
>
>  static void kasan_bitops_test_and_modify(struct kunit *test, int nr, void *addr)
>  {
> +       int kasan_int_result;
> +
>         KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit(nr, addr));
>         KUNIT_EXPECT_KASAN_FAIL(test, __test_and_set_bit(nr, addr));
>         KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit_lock(nr, addr));
> --
> 2.34.1
>
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