From: Nicolin Chen Date: Tue, 24 Jun 2025 18:00:48 +0000 (-0700) Subject: iommufd/selftest: Fix build warnings due to uninitialized mfd X-Git-Tag: v6.16-rc5~33^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9a96876e3c6578031fa5dc5dde7759d383b2fb75;p=thirdparty%2Flinux.git iommufd/selftest: Fix build warnings due to uninitialized mfd 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(). Link: https://patch.msgid.link/r/6951d85d5cd34cbf22abab7714542654e63ecc44.1750787928.git.nicolinc@nvidia.com Reviewed-by: Jason Gunthorpe Signed-off-by: Nicolin Chen Signed-off-by: Jason Gunthorpe --- diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c index e61218c0537f2..1926ef6b40abd 100644 --- a/tools/testing/selftests/iommu/iommufd.c +++ b/tools/testing/selftests/iommu/iommufd.c @@ -1748,13 +1748,15 @@ 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); /* @@ -1800,13 +1802,15 @@ 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); /*