Re: [PATCH] kunit/overflow: Fix UB in overflow_allocation_test

[David Gow]

On Thu, 15 Aug 2024 at 08:04, Ivan Orlov <ivan.orlov0322@xxxxxxxxx> wrote:
>
> The 'device_name' array doesn't exist out of the
> 'overflow_allocation_test' function scope. However, it is being used as
> a driver name when calling 'kunit_driver_create' from
> 'kunit_device_register'. It produces the kernel panic with KASAN
> enabled.
>
> Since this variable is used in one place only, remove it and pass the
> device name into kunit_device_register directly as an ascii string.
>
> Signed-off-by: Ivan Orlov <ivan.orlov0322@xxxxxxxxx>
> ---

Thanks -- we've got plans to add support for non-constant strings
here, but the first version had some issues, and (Kees -- correct me
if I'm wrong) there doesn't seem to be any need to have this be
dynamically allocated.

Reviewed-by: David Gow <davidgow@xxxxxxxxxx>

Cheers,
-- David

>  lib/overflow_kunit.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c
> index f314a0c15a6d..2abc78367dd1 100644
> --- a/lib/overflow_kunit.c
> +++ b/lib/overflow_kunit.c
> @@ -668,7 +668,6 @@ DEFINE_TEST_ALLOC(devm_kzalloc,  devm_kfree, 1, 1, 0);
>
>  static void overflow_allocation_test(struct kunit *test)
>  {
> -       const char device_name[] = "overflow-test";
>         struct device *dev;
>         int count = 0;
>
> @@ -678,7 +677,7 @@ static void overflow_allocation_test(struct kunit *test)
>  } while (0)
>
>         /* Create dummy device for devm_kmalloc()-family tests. */
> -       dev = kunit_device_register(test, device_name);
> +       dev = kunit_device_register(test, "overflow-test");
>         KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev),
>                                "Cannot register test device\n");
>
> --
> 2.34.1
>

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