dm crypt: allow unaligned bv_offset

When slub_debug is enabled kmalloc returns unaligned memory. XFS uses
this unaligned memory for its buffers (if an unaligned buffer crosses a
page, XFS frees it and allocates a full page instead - see the function
xfs_buf_allocate_memory).

dm-crypt checks if bv_offset is aligned on page size and these checks
fail with slub_debug and XFS.

Fix this bug by removing the bv_offset checks. Switch to checking if
bv_len is aligned instead of bv_offset (this check should be sufficient
to prevent overruns if a bio with too small bv_len is received).

Fixes: 8f0009a22517 ("dm crypt: optionally support larger encryption sector size")
Cc: [email protected] # v4.12+
Reported-by: Bruno Prémont <[email protected]>
Tested-by: Bruno Prémont <[email protected]>
Signed-off-by: Mikulas Patocka <[email protected]>
Reviewed-by: Milan Broz <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>

0 files changed, 0 insertions, 0 deletions