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| author | Jason Gunthorpe <jgg@nvidia.com> | 2025-12-05 14:56:12 -0400 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2025-12-15 20:34:41 -0400 |
| commit | 5b244b077c0b0e76573fbb9542cf038e42368901 (patch) | |
| tree | d64614ee1fe5c73036fce1577b9c5dd77e9f8dc2 | |
| parent | 69dc538a4f5a57dcc5ea4893c769d567f539a1b1 (diff) | |
iommufd/selftest: Make it clearer to gcc that the access is not out of bounds
GCC gets a bit confused and reports:
In function '_test_cmd_get_hw_info',
inlined from 'iommufd_ioas_get_hw_info' at iommufd.c:779:3,
inlined from 'wrapper_iommufd_ioas_get_hw_info' at iommufd.c:752:1:
>> iommufd_utils.h:804:37: warning: array subscript 'struct iommu_test_hw_info[0]' is partly outside array bounds of 'struct iommu_test_hw_info_buffer_smaller[1]' [-Warray-bounds=]
804 | assert(!info->flags);
| ~~~~^~~~~~~
iommufd.c: In function 'wrapper_iommufd_ioas_get_hw_info':
iommufd.c:761:11: note: object 'buffer_smaller' of size 4
761 | } buffer_smaller;
| ^~~~~~~~~~~~~~
While it is true that "struct iommu_test_hw_info[0]" is partly out of
bounds of the input pointer, it is not true that info->flags is out of
bounds. Unclear why it warns on this.
Reuse an existing properly sized stack buffer and pass a truncated length
instead to test the same thing.
Fixes: af4fde93c319 ("iommufd/selftest: Add coverage for IOMMU_GET_HW_INFO ioctl")
Link: https://patch.msgid.link/r/0-v1-63a2cffb09da+4486-iommufd_gcc_bounds_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512032344.kaAcKFIM-lkp@intel.com/
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
| -rw-r--r-- | tools/testing/selftests/iommu/iommufd.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c index 10e051b6f592..dadad277f4eb 100644 --- a/tools/testing/selftests/iommu/iommufd.c +++ b/tools/testing/selftests/iommu/iommufd.c @@ -755,9 +755,6 @@ TEST_F(iommufd_ioas, get_hw_info) struct iommu_test_hw_info info; uint64_t trailing_bytes; } buffer_larger; - struct iommu_test_hw_info_buffer_smaller { - __u32 flags; - } buffer_smaller; if (self->device_id) { uint8_t max_pasid = 0; @@ -789,8 +786,9 @@ TEST_F(iommufd_ioas, get_hw_info) * the fields within the size range still gets updated. */ test_cmd_get_hw_info(self->device_id, - IOMMU_HW_INFO_TYPE_DEFAULT, - &buffer_smaller, sizeof(buffer_smaller)); + IOMMU_HW_INFO_TYPE_DEFAULT, &buffer_exact, + offsetofend(struct iommu_test_hw_info, + flags)); test_cmd_get_hw_info_pasid(self->device_id, &max_pasid); ASSERT_EQ(0, max_pasid); if (variant->pasid_capable) { |