6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Song Liu <song@xxxxxxxxxx>
commit 45b478951b2ba5aea70b2850c49c1aa83aedd0d2 upstream.
md_end_clone_io() may overwrite error status in orig_bio->bi_status with
BLK_STS_OK. This could happen when orig_bio has BIO_CHAIN (split by
md_submit_bio => bio_split_to_limits, for example). As a result, upper
layer may miss error reported from md (or the device) and consider the
failed IO was successful.
Fix this by only update orig_bio->bi_status when current bio reports
error and orig_bio is BLK_STS_OK. This is the same behavior as
__bio_chain_endio().
Fixes: 10764815ff47 ("md: add io accounting for raid0 and raid5")
Cc: stable@xxxxxxxxxxxxxxx # v5.14+
Reported-by: Bhanu Victor DiCara <00bvd0+linux@xxxxxxxxx>
Closes: https://lore.kernel.org/regressions/5727380.DvuYhMxLoT@bvd0/
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Tested-by: Xiao Ni <xni@xxxxxxxxxx>
Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Acked-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/md.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8669,7 +8669,8 @@ static void md_end_clone_io(struct bio *
struct bio *orig_bio = md_io_clone->orig_bio;
struct mddev *mddev = md_io_clone->mddev;
- orig_bio->bi_status = bio->bi_status;
+ if (bio->bi_status && !orig_bio->bi_status)
+ orig_bio->bi_status = bio->bi_status;
if (md_io_clone->start_time)
bio_end_io_acct(orig_bio, md_io_clone->start_time);
