iommufd/selftest: Fix buffer read overrrun in the dirty test

test_bit() is used to read the memory storing the bitmap, however
test_bit() always uses a unsigned long 8 byte access.

If the bitmap is not an aligned size of 64 bits this will now trigger a
KASAN warning reading past the end of the buffer.

Properly round the buffer allocation to an unsigned long size. Continue to
copy_from_user() using a byte granularity.

Fixes: 9560393b830b ("iommufd/selftest: Fix iommufd_test_dirty() to handle <u8 bitmaps")
Link: https://patch.msgid.link/r/[email protected]
Reviewed-by: Joao Martins <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

0 files changed, 0 insertions, 0 deletions