On Tue, Sep 23, 2025 at 11:38:13PM +0200, Alessandro Zanni wrote:

On Tue, Sep 23, 2025 at 02:28:22PM -0300, Jason Gunthorpe wrote:

...

On Tue, Sep 23, 2025 at 05:01:06PM +0200, Alessandro Zanni wrote:

...

Fix to avoid the usage of the `res` variable uninitialized in the following macro expansions.

It solves the following warning: In function ‘iommufd_viommu_vdevice_alloc’, inlined from ‘wrapper_iommufd_viommu_vdevice_alloc’ at iommufd.c:2889:1: ../kselftest_harness.h:760:12: warning: ‘ret’ may be used uninitialized [-Wmaybe-uninitialized] 760 | if (!(__exp _t __seen)) { \ | ^ ../kselftest_harness.h:513:9: note: in expansion of macro ‘__EXPECT’ 513 | __EXPECT(expected, #expected, seen, #seen, ==, 1) | ^~~~~~~~ iommufd_utils.h:1057:9: note: in expansion of macro ‘ASSERT_EQ’ 1057 | ASSERT_EQ(0, _test_cmd_trigger_vevents(self->fd, dev_id, nvevents)) | ^~~~~~~~~ iommufd.c:2924:17: note: in expansion of macro ‘test_cmd_trigger_vevents’ 2924 | test_cmd_trigger_vevents(dev_id, 3); | ^~~~~~~~~~~~~~~~~~~~~~~~

The issue can be reproduced, building the tests, with the command: make -C tools/testing/selftests TARGETS=iommu

Signed-off-by: Alessandro Zanni alessandro.zanni87@gmail.com

tools/testing/selftests/iommu/iommufd_utils.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

I think it should be like this?

@@ -1042,15 +1042,12 @@ static int _test_cmd_trigger_vevents(int fd, __u32 dev_id, __u32 nvevents) .dev_id = dev_id, }, };

•   int ret;
  

•   while (nvevents--) {
  

•           ret = ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_TRIGGER_VEVENT),
  

•                       &trigger_vevent_cmd);
  

•           if (ret < 0)
  

•   while (nvevents--)
  

•           if (ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_TRIGGER_VEVENT),
  

•                     &trigger_vevent_cmd))
                    return -1;
  

•   }
  

•   return ret;
  

•   return 0;
  

}

And add a fixes line?

Jason

Thank you for the reply. I'm not sure the right behavior the test should have:

• in the version you proposed, when ioctl() returns a positive

value the loop ends and the next tests are skipped.

• in the original version, if the function ioctl() returns a

positive value the loop continues with the following tests.

Which one is the desired behavior?

Sorry it should be !ioctl()

The ioctl will only return 0 or -errno

Jason