From: Mike Snitzer <snitzer@xxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxx
Reported-by: Orange Kao <orange@xxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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);
--
2.39.2
