4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xiao Ni <x...@redhat.com>
[ Upstream commit 1d0ffd264204eba1861865560f1f7f7a92919384 ]
In raid10 reshape_request it gets max_sectors in read_balance. If the
underlayer disks
have bad blocks, the max_sectors is less than last. It will call goto read_more
many
times. It calls raise_barrier(conf, sectors_done != 0) every time. In this
condition
sectors_done is not 0. So the value passed to the argument force of
raise_barrier is
true.
In raise_barrier it checks conf->barrier when force is true. If force is true
and
conf->barrier is 0, it panic. In this case reshape_request submits bio to under
layer
disks. And in the callback function of the bio it calls lower_barrier. If the
bio
finishes before calling raise_barrier again, it can trigger the BUG_ON.
Add one pair of raise_barrier/lower_barrier to fix this bug.
Signed-off-by: Xiao Ni <x...@redhat.com>
Suggested-by: Neil Brown <ne...@suse.com>
Signed-off-by: Shaohua Li <s...@fb.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/md/raid10.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4531,11 +4531,12 @@ static sector_t reshape_request(struct m
allow_barrier(conf);
}
+ raise_barrier(conf, 0);
read_more:
/* Now schedule reads for blocks from sector_nr to last */
r10_bio = raid10_alloc_init_r10buf(conf);
r10_bio->state = 0;
- raise_barrier(conf, sectors_done != 0);
+ raise_barrier(conf, 1);
atomic_set(&r10_bio->remaining, 0);
r10_bio->mddev = mddev;
r10_bio->sector = sector_nr;
@@ -4631,6 +4632,8 @@ read_more:
if (sector_nr <= last)
goto read_more;
+ lower_barrier(conf);
+
/* Now that we have done the whole section we can
* update reshape_progress
*/
