From: Mikulas Patocka mpatocka@redhat.com
stable inclusion from stable-v6.6.9 commit 3b664557b12fcf8acd3df595afbd184c82a97f8b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8SU2D
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit b86f4b790c998afdbc88fe1aa55cfe89c4068726 upstream.
__bio_for_each_segment assumes that the first struct bio_vec argument doesn't change - it calls "bio_advance_iter_single((bio), &(iter), (bvl).bv_len)" to advance the iterator. Unfortunately, the dm-integrity code changes the bio_vec with "bv.bv_len -= pos". When this code path is taken, the iterator would be out of sync and dm-integrity would report errors. This happens if the machine is out of memory and "kmalloc" fails.
Fix this bug by making a copy of "bv" and changing the copy instead.
Fixes: 7eada909bfd7 ("dm: add integrity target") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Mike Snitzer snitzer@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/md/dm-integrity.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index 97a8d5fc9ebb..9261bbebd662 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -1765,11 +1765,12 @@ static void integrity_metadata(struct work_struct *w) sectors_to_process = dio->range.n_sectors;
__bio_for_each_segment(bv, bio, iter, dio->bio_details.bi_iter) { + struct bio_vec bv_copy = bv; unsigned int pos; char *mem, *checksums_ptr;
again: - mem = bvec_kmap_local(&bv); + mem = bvec_kmap_local(&bv_copy); pos = 0; checksums_ptr = checksums; do { @@ -1778,7 +1779,7 @@ static void integrity_metadata(struct work_struct *w) sectors_to_process -= ic->sectors_per_block; pos += ic->sectors_per_block << SECTOR_SHIFT; sector += ic->sectors_per_block; - } while (pos < bv.bv_len && sectors_to_process && checksums != checksums_onstack); + } while (pos < bv_copy.bv_len && sectors_to_process && checksums != checksums_onstack); kunmap_local(mem);
r = dm_integrity_rw_tag(ic, checksums, &dio->metadata_block, &dio->metadata_offset, @@ -1803,9 +1804,9 @@ static void integrity_metadata(struct work_struct *w) if (!sectors_to_process) break;
- if (unlikely(pos < bv.bv_len)) { - bv.bv_offset += pos; - bv.bv_len -= pos; + if (unlikely(pos < bv_copy.bv_len)) { + bv_copy.bv_offset += pos; + bv_copy.bv_len -= pos; goto again; } }