md/raid10: initialize r10_bio->read_slot before use. (93decc56) · Commits · 戴 / test

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 <kvigor@gmail.com> Signed-off-by:

Song Liu <songliubraving@fb.com>

drivers/md/raid10.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1127,7 +1127,7 @@ 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,
		@@ -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->geo.raid_disks);

		if (bio_data_dir(bio) == READ)

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