releases/4.14.3/dm-integrity-allow-unaligned-bv_offset.patch

   1 From 95b1369a9638cfa322ad1c0cde8efbe524059884 Mon Sep 17 00:00:00 2001
   2 From: Mikulas Patocka <mpatocka@redhat.com>
   3 Date: Tue, 7 Nov 2017 10:40:40 -0500
   4 Subject: dm integrity: allow unaligned bv_offset
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   8
   9 From: Mikulas Patocka <mpatocka@redhat.com>
  10
  11 commit 95b1369a9638cfa322ad1c0cde8efbe524059884 upstream.
  12
  13 When slub_debug is enabled kmalloc returns unaligned memory. XFS uses
  14 this unaligned memory for its buffers (if an unaligned buffer crosses a
  15 page, XFS frees it and allocates a full page instead - see the function
  16 xfs_buf_allocate_memory).
  17
  18 dm-integrity checks if bv_offset is aligned on page size and this check
  19 fail with slub_debug and XFS.
  20
  21 Fix this bug by removing the bv_offset check, leaving only the check for
  22 bv_len.
  23
  24 Fixes: 7eada909bfd7 ("dm: add integrity target")
  25 Reported-by: Bruno Prémont <bonbons@sysophe.eu>
  26 Reviewed-by: Milan Broz <gmazyland@gmail.com>
  27 Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
  28 Signed-off-by: Mike Snitzer <snitzer@redhat.com>
  29 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  30
  31 ---
  32  drivers/md/dm-integrity.c |    2 +-
  33  1 file changed, 1 insertion(+), 1 deletion(-)
  34
  35 --- a/drivers/md/dm-integrity.c
  36 +++ b/drivers/md/dm-integrity.c
  37 @@ -1376,7 +1376,7 @@ static int dm_integrity_map(struct dm_ta
  38                 struct bvec_iter iter;
  39                 struct bio_vec bv;
  40                 bio_for_each_segment(bv, bio, iter) {
  41 -                       if (unlikely((bv.bv_offset | bv.bv_len) & ((ic->sectors_per_block << SECTOR_SHIFT) - 1))) {
  42 +                       if (unlikely(bv.bv_len & ((ic->sectors_per_block << SECTOR_SHIFT) - 1))) {
  43                                 DMERR("Bio vector (%u,%u) is not aligned on %u-sector boundary",
  44                                         bv.bv_offset, bv.bv_len, ic->sectors_per_block);
  45                                 return DM_MAPIO_KILL;