The mfd and mfd_buffer will be used in the tests directly without an extra
check. Test them in setup_sizes() to ensure they are safe to use.

Fixes: 0bcceb1f51c7 ("iommufd: Selftest coverage for IOMMU_IOAS_MAP_FILE")
Cc: stable@vger.kernel.org
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 tools/testing/selftests/iommu/iommufd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index 602f8540242b..393d95f88ad4 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -55,6 +55,8 @@ static __attribute__((constructor)) void setup_sizes(void)
 
 	mfd_buffer = memfd_mmap(BUFFER_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
 				&mfd);
+	assert(mfd_buffer != MAP_FAILED);
+	assert(mfd > 0);
 }
 
 FIXTURE(iommufd)
-- 
2.43.0

On Sun, Jun 15, 2025 at 10:02:05PM -0700, Nicolin Chen wrote:
> The mfd and mfd_buffer will be used in the tests directly without an extra
> check. Test them in setup_sizes() to ensure they are safe to use.
> 
> Fixes: 0bcceb1f51c7 ("iommufd: Selftest coverage for IOMMU_IOAS_MAP_FILE")
> Cc: stable@vger.kernel.org
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  tools/testing/selftests/iommu/iommufd.c | 2 ++
>  1 file changed, 2 insertions(+)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason