Commit 84255d10 authored May 23, 2008 by NeilBrown Committed by Linus Torvalds May 24, 2008

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>

parent 80119ef5

drivers/md/raid1.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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));

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