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iommufd/selftest: Fix build warnings due to uninitialized mfd

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Commit 869c788909 ("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 <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Nicolin Chen 2025-06-24 11:00:48 -07:00 committed by Jason Gunthorpe
parent a9bf67ee17
commit 9a96876e3c
1 changed files with 6 additions and 2 deletions
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8
tools/testing/selftests/iommu/iommufd.c
View File

@ -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);
/*