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Commit 84255d10 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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md: fix possible oops when removing a bitmap from an active array 



It is possible to add a write-intent bitmap to an active array, or remove
the bitmap that is there.

When we do with the 'quiesce' the array, which causes make_request to
block in "wait_barrier()".

However we are sampling the value of "mddev->bitmap" before the
wait_barrier call, and using it afterwards.  This can result in using a
bitmap structure that has been freed.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 80119ef5

drivers/md/raid1.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -773,7 +773,7 @@ static int make_request(struct request_queue *q, struct bio * bio) 
	r1bio_t *r1_bio;

	r1bio_t *r1_bio;

	struct bio *read_bio;

	struct bio *read_bio;

	int i, targets = 0, disks;

	int i, targets = 0, disks;

	struct bitmap *bitmap = mddev->bitmap;

	struct bitmap *bitmap;

	unsigned long flags;

	unsigned long flags;

	struct bio_list bl;

	struct bio_list bl;

	struct page **behind_pages = NULL;

	struct page **behind_pages = NULL;
@@ -802,6 +802,8 @@ static int make_request(struct request_queue *q, struct bio * bio) 




	wait_barrier(conf);

	wait_barrier(conf);





	bitmap = mddev->bitmap;



	disk_stat_inc(mddev->gendisk, ios[rw]);

	disk_stat_inc(mddev->gendisk, ios[rw]);

	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));

	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));