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?
Thanks, Alessandro