On Thu, Nov 5, 2020 at 10:08 AM Kevin Vigor <kvigor@xxxxxxxxx> wrote:
>
> In __make_request() a new r10bio is allocated and passed to
> raid10_read_request(). The read_slot member of the bio is not
> initialized, and the raid10_read_request() uses it to index an
> array. This leads to occasional panics.
>
> Fix by initializing the field to invalid value and checking for
> valid value in raid10_read_request().
>
> Signed-off-by: Kevin Vigor <kvigor@xxxxxxxxx>
Thanks for the fix!
I am having problem apply this patch, could you please rebase against
git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git md-next
> ---
> drivers/md/raid10.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 8a1354a08a1a..64b1306b0c4a 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -1143,7 +1143,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
> struct md_rdev *err_rdev = NULL;
> gfp_t gfp = GFP_NOIO;
>
> - if (r10_bio->devs[slot].rdev) {
> + if (slot >= 0 && r10_bio->devs[slot].rdev) {
If we set default read_slot = 0, we should not need this change, right?
> /*
> * This is an error retry, but we cannot
> * safely dereference the rdev in the r10_bio,
> @@ -1508,6 +1508,7 @@ static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
> r10_bio->mddev = mddev;
> r10_bio->sector = bio->bi_iter.bi_sector;
> r10_bio->state = 0;
> + r10_bio->read_slot = -1;
> memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * conf->copies);
>
> if (bio_data_dir(bio) == READ)
> --
> 2.26.2
>
