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+ReF3v3Rlf@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 nicolinc@nvidia.com --- tools/testing/selftests/iommu/iommufd.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c index 393d95f88ad4..ca611ae5925f 100644 --- a/tools/testing/selftests/iommu/iommufd.c +++ b/tools/testing/selftests/iommu/iommufd.c @@ -1749,13 +1749,15 @@ TEST_F(iommufd_mock_domain, all_aligns) unsigned int end; uint8_t *buf; int prot = PROT_READ | PROT_WRITE; - int mfd; + int mfd = -1;
if (variant->file) buf = memfd_mmap(buf_size, prot, MAP_SHARED, &mfd); else buf = mmap(0, buf_size, prot, self->mmap_flags, -1, 0); ASSERT_NE(MAP_FAILED, buf); + if (variant->file) + ASSERT_GT(mfd, 0); check_refs(buf, buf_size, 0);
/* @@ -1801,13 +1803,15 @@ TEST_F(iommufd_mock_domain, all_aligns_copy) unsigned int end; uint8_t *buf; int prot = PROT_READ | PROT_WRITE; - int mfd; + int mfd = -1;
if (variant->file) buf = memfd_mmap(buf_size, prot, MAP_SHARED, &mfd); else buf = mmap(0, buf_size, prot, self->mmap_flags, -1, 0); ASSERT_NE(MAP_FAILED, buf); + if (variant->file) + ASSERT_GT(mfd, 0); check_refs(buf, buf_size, 0);
/*