Invalid prctls return a negative code and set errno. It's good practice
to check that errno is set as expected.

Signed-off-by: Florent Revest <revest@chromium.org>
---
 tools/testing/selftests/mm/mdwe_test.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
index 91aa9c3099e7..1b84cf8e1bbe 100644
--- a/tools/testing/selftests/mm/mdwe_test.c
+++ b/tools/testing/selftests/mm/mdwe_test.c
@@ -23,14 +23,22 @@
 TEST(prctl_flags)
 {
 	EXPECT_LT(prctl(PR_SET_MDWE, 7L, 0L, 0L, 0L), 0);
+	EXPECT_EQ(errno, EINVAL);
 	EXPECT_LT(prctl(PR_SET_MDWE, 0L, 7L, 0L, 0L), 0);
+	EXPECT_EQ(errno, EINVAL);
 	EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 7L, 0L), 0);
+	EXPECT_EQ(errno, EINVAL);
 	EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 0L, 7L), 0);
+	EXPECT_EQ(errno, EINVAL);
 
 	EXPECT_LT(prctl(PR_GET_MDWE, 7L, 0L, 0L, 0L), 0);
+	EXPECT_EQ(errno, EINVAL);
 	EXPECT_LT(prctl(PR_GET_MDWE, 0L, 7L, 0L, 0L), 0);
+	EXPECT_EQ(errno, EINVAL);
 	EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 7L, 0L), 0);
+	EXPECT_EQ(errno, EINVAL);
 	EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 0L, 7L), 0);
+	EXPECT_EQ(errno, EINVAL);
 }
 
 FIXTURE(mdwe)
-- 
2.42.0.rc2.253.gd59a3bf2b4-goog

On Mon, Aug 28, 2023 at 05:08:55PM +0200, Florent Revest wrote:
> Invalid prctls return a negative code and set errno. It's good practice
> to check that errno is set as expected.
> 
> Signed-off-by: Florent Revest <revest@chromium.org>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

On Mon, Aug 28, 2023 at 05:08:55PM +0200, Florent Revest wrote:
> Invalid prctls return a negative code and set errno. It's good practice
> to check that errno is set as expected.
> 
> Signed-off-by: Florent Revest <revest@chromium.org>

Thanks!

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook