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Commit c9445555 authored by Shaohua Li's avatar Shaohua Li
Browse files

raid5: fix a small race condition 



commit 5f9d1fde(raid5: fix memory leak of bio integrity data)
moves bio_reset to bio_endio. But it introduces a small race condition.
It does bio_reset after raid5_release_stripe, which could make the
stripe reusable and hence reuse the bio just before bio_reset. Moving
bio_reset before raid5_release_stripe is called should fix the race.

Reported-and-tested-by: default avatarStefan Priebe - Profihost AG <s.priebe@profihost.ag>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 47a7b0d8

drivers/md/raid5.c

+2 −2
Original line number Diff line number Diff line
@@ -2423,10 +2423,10 @@ static void raid5_end_read_request(struct bio * bi) 
		}

	}

	rdev_dec_pending(rdev, conf->mddev);

	bio_reset(bi);

	clear_bit(R5_LOCKED, &sh->dev[i].flags);

	set_bit(STRIPE_HANDLE, &sh->state);

	raid5_release_stripe(sh);

	bio_reset(bi);

}



static void raid5_end_write_request(struct bio *bi)
@@ -2498,6 +2498,7 @@ static void raid5_end_write_request(struct bio *bi) 
	if (sh->batch_head && bi->bi_error && !replacement)

		set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);



	bio_reset(bi);

	if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))

		clear_bit(R5_LOCKED, &sh->dev[i].flags);

	set_bit(STRIPE_HANDLE, &sh->state);
@@ -2505,7 +2506,6 @@ static void raid5_end_write_request(struct bio *bi) 


	if (sh->batch_head && sh != sh->batch_head)

		raid5_release_stripe(sh->batch_head);

	bio_reset(bi);

}



static void raid5_build_block(struct stripe_head *sh, int i, int previous)