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Commit cc7da0ba authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
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dm cache: fix use after freeing migrations 



Both free_io_migration() and issue_discard() dereference a migration
that was just freed.  Fix those by saving off the migrations's cache
object before freeing the migration.  Also cleanup needless mg->cache
dereferences now that the cache object is available directly.

Fixes: e44b6a5a ("dm cache: move wake_waker() from free_migrations() to where it is needed")
Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent dc9cee5d

drivers/md/dm-cache-target.c

+9 −6
Original line number Diff line number Diff line
@@ -1113,9 +1113,11 @@ static void cell_requeue(struct cache *cache, struct dm_bio_prison_cell *cell) 


static void free_io_migration(struct dm_cache_migration *mg)

{

	dec_io_migrations(mg->cache);

	struct cache *cache = mg->cache;



	dec_io_migrations(cache);

	free_migration(mg);

	wake_worker(mg->cache);

	wake_worker(cache);

}



static void migration_failure(struct dm_cache_migration *mg)
@@ -1342,17 +1344,18 @@ static void issue_discard(struct dm_cache_migration *mg) 
{

	dm_dblock_t b, e;

	struct bio *bio = mg->new_ocell->holder;

	struct cache *cache = mg->cache;



	calc_discard_block_range(mg->cache, bio, &b, &e);

	calc_discard_block_range(cache, bio, &b, &e);

	while (b != e) {

		set_discard(mg->cache, b);

		set_discard(cache, b);

		b = to_dblock(from_dblock(b) + 1);

	}



	bio_endio(bio, 0);

	cell_defer(mg->cache, mg->new_ocell, false);

	cell_defer(cache, mg->new_ocell, false);

	free_migration(mg);

	wake_worker(mg->cache);

	wake_worker(cache);

}



static void issue_copy_or_discard(struct dm_cache_migration *mg)