From: Mike Snitzer snitzer@kernel.org
[ Upstream commit f7b58a69fad9d2c4c90cab0247811155dd0d48e7 ]
"Abnormal" bios include discards, write zeroes and secure erase. By no longer passing the calculated 'len' pointer, commit 7dd06a2548b2 ("dm: allow dm_accept_partial_bio() for dm_io without duplicate bios") took a senseless approach to disallowing dm_accept_partial_bio() from working for duplicate bios processed using __send_duplicate_bios().
It inadvertently and incorrectly stopped the use of 'len' when initializing a target's io (in alloc_tio). As such the resulting tio could address more area of a device than it should.
For example, when discarding an entire DM striped device with the following DM table: vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048 vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048
Before this fix:
device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=102400 blkdiscard: attempt to access beyond end of device loop0: rw=2051, sector=2048, nr_sectors = 102400 limit=81920
device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=102400 blkdiscard: attempt to access beyond end of device loop1: rw=2051, sector=2048, nr_sectors = 102400 limit=81920
After this fix;
device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872
Fixes: 7dd06a2548b2 ("dm: allow dm_accept_partial_bio() for dm_io without duplicate bios") Cc: stable@vger.kernel.org Reported-by: Orange Kao orange@aiven.io Signed-off-by: Mike Snitzer snitzer@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/dm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 94e4899d8ac7c..cdbf24def8af3 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1462,7 +1462,8 @@ static void setup_split_accounting(struct clone_info *ci, unsigned int len) }
static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci, - struct dm_target *ti, unsigned int num_bios) + struct dm_target *ti, unsigned int num_bios, + unsigned *len) { struct bio *bio; int try; @@ -1473,7 +1474,7 @@ static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci, if (try) mutex_lock(&ci->io->md->table_devices_lock); for (bio_nr = 0; bio_nr < num_bios; bio_nr++) { - bio = alloc_tio(ci, ti, bio_nr, NULL, + bio = alloc_tio(ci, ti, bio_nr, len, try ? GFP_NOIO : GFP_NOWAIT); if (!bio) break; @@ -1511,7 +1512,7 @@ static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti, if (len) setup_split_accounting(ci, *len); /* dm_accept_partial_bio() is not supported with shared tio->len_ptr */ - alloc_multiple_bios(&blist, ci, ti, num_bios); + alloc_multiple_bios(&blist, ci, ti, num_bios, len); while ((clone = bio_list_pop(&blist))) { dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO); __map_bio(clone);