From f8bd479859c9431bf0e951948f76c75e8953d6bd Mon Sep 17 00:00:00 2001 From: Kevin Vigor Date: Fri, 6 Nov 2020 14:20:34 -0800 Subject: md/raid10: initialize r10_bio->read_slot before use. commit 93decc563637c4288380912eac0eb42fb246cc04 upstream. 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(). Cc: stable@vger.kernel.org Signed-off-by: Kevin Vigor Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid10.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/md') diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 02c5e390f89f..8e0f936b3e37 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1138,7 +1138,7 @@ 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) { /* * This is an error retry, but we cannot * safely dereference the rdev in the r10_bio, @@ -1547,6 +1547,7 @@ 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) -- cgit v1.2.3