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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: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
NeilBrown 2008-05-23 13:04:32 -07:00 committed by Linus Torvalds
parent 80119ef5c8
commit 84255d1018
1 changed files with 3 additions and 1 deletions
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4
drivers/md/raid1.c
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@ -773,7 +773,7 @@ static int make_request(struct request_queue *q, struct bio * bio)
r1bio_t *r1_bio;
struct bio *read_bio;
int i, targets = 0, disks;
struct bitmap *bitmap = mddev->bitmap;
struct bitmap *bitmap;
unsigned long flags;
struct bio_list bl;
struct page **behind_pages = NULL;
@ -802,6 +802,8 @@ static int make_request(struct request_queue *q, struct bio * bio)
wait_barrier(conf);
bitmap = mddev->bitmap;
disk_stat_inc(mddev->gendisk, ios[rw]);
disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));