On Sun, Jun 15, 2025 at 10:02:06PM -0700, Nicolin Chen wrote:
> Commit 869c788909b9 ("selftests: harness: Stop using setjmp()/longjmp()")
> changed the harness structure. For some unknown reason, two build warnings
> occur to the iommufd selftest:
>
> iommufd.c: In function ‘wrapper_iommufd_mock_domain_all_aligns’:
> iommufd.c:1807:17: warning: ‘mfd’ may be used uninitialized in this function
> 1807 | close(mfd);
> | ^~~~~~~~~~
> iommufd.c:1767:13: note: ‘mfd’ was declared here
> 1767 | int mfd;
> | ^~~
> iommufd.c: In function ‘wrapper_iommufd_mock_domain_all_aligns_copy’:
> iommufd.c:1870:17: warning: ‘mfd’ may be used uninitialized in this function
> 1870 | close(mfd);
> | ^~~~~~~~~~
> iommufd.c:1819:13: note: ‘mfd’ was declared here
> 1819 | int mfd;
> | ^~~
>
> All the mfd have been used in the variant->file path only, so it's likely
> a false alarm.
>
> FWIW, the commit mentioned above does not cause this, yet it might affect
> gcc in a certain way that resulted in the warnings. It is also found that
> ading a dummy setjmp (which doesn't make sense) could mute the warnings:
> https://lore.kernel.org/all/aei8dv+ref3v3...@nvidia.com/
>
> The job of this selftest is to catch kernel bug, while such warnings will
> unlikely disrupt its role. Mute the warning by force initializing the mfd
> and add an ASSERT_GT().
>
> Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
> ---
> tools/testing/selftests/iommu/iommufd.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
Reviewed-by: Jason Gunthorpe <j...@nvidia.com>
Jason
