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 <[email protected]>
> > ---
> > 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?
Thanks,
Alessandro
