When CONFIG_FORTIFY_SOURCE is enabled, invalid access from source
triggers __fortify_panic() which kills running task.

This makes failured of kasan_strings() kunit testcase since the
kunit-try-cacth kthread running kasan_string() dies before checking the
fault.

To address this, skip kasan_strings() kunit test when
CONFIG_FORTIFY_SOURCE is enabled.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 mm/kasan/kasan_test_c.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
index 5f922dd38ffa..1577d3edabb4 100644
--- a/mm/kasan/kasan_test_c.c
+++ b/mm/kasan/kasan_test_c.c
@@ -1576,6 +1576,12 @@ static void kasan_strings(struct kunit *test)
 	 */
 	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);

+	/*
+	 * Harden common str/mem functions kills the kunit-try-catch thread
+	 * before checking the fault.
+	 */
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_FORTIFY_SOURCE);
+
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);

--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}

On Thu, Jul 31, 2025 at 10:02:46AM +0100, Yeoreum Yun wrote:
> When CONFIG_FORTIFY_SOURCE is enabled, invalid access from source
> triggers __fortify_panic() which kills running task.
> 
> This makes failured of kasan_strings() kunit testcase since the
> kunit-try-cacth kthread running kasan_string() dies before checking the
> fault.
> 
> To address this, skip kasan_strings() kunit test when
> CONFIG_FORTIFY_SOURCE is enabled.
> 
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
>  mm/kasan/kasan_test_c.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
> index 5f922dd38ffa..1577d3edabb4 100644
> --- a/mm/kasan/kasan_test_c.c
> +++ b/mm/kasan/kasan_test_c.c
> @@ -1576,6 +1576,12 @@ static void kasan_strings(struct kunit *test)
>  	 */
>  	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
> 
> +	/*
> +	 * Harden common str/mem functions kills the kunit-try-catch thread
> +	 * before checking the fault.
> +	 */
> +	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_FORTIFY_SOURCE);

Would it be enough to enable -D__NO_FORTIFY for the whole of kasan_test_c.c?

> +
>  	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
>  	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> 
> --
> LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
>

Hi Thomas,

> > When CONFIG_FORTIFY_SOURCE is enabled, invalid access from source
> > triggers __fortify_panic() which kills running task.
> >
> > This makes failured of kasan_strings() kunit testcase since the
> > kunit-try-cacth kthread running kasan_string() dies before checking the
> > fault.
> >
> > To address this, skip kasan_strings() kunit test when
> > CONFIG_FORTIFY_SOURCE is enabled.
> >
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> > ---
> >  mm/kasan/kasan_test_c.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
> > index 5f922dd38ffa..1577d3edabb4 100644
> > --- a/mm/kasan/kasan_test_c.c
> > +++ b/mm/kasan/kasan_test_c.c
> > @@ -1576,6 +1576,12 @@ static void kasan_strings(struct kunit *test)
> >  	 */
> >  	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
> >
> > +	/*
> > +	 * Harden common str/mem functions kills the kunit-try-catch thread
> > +	 * before checking the fault.
> > +	 */
> > +	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_FORTIFY_SOURCE);
>
> Would it be enough to enable -D__NO_FORTIFY for the whole of kasan_test_c.c?

It would be better. I'll add it to Makefile unless other comment is.

Thanks!

[...]
--
Sincerely,
Yeoreum Yun