Re: [PATCH] md/raid10: initialize r10_bio->read_slot before use.
From: Song Liu <song@kernel.org>
Date: 2020-11-06 21:57:02
On Thu, Nov 5, 2020 at 10:08 AM Kevin Vigor [off-list ref] 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 <redacted>
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
quoted hunk ↗ jump to hunk
--- 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?
quoted hunk ↗ jump to hunk
/* * 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