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5b244b077c
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: af4fde93c3 ("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>