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: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed")
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index e13e5ed..f9d9cc6 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1113,9 +1113,11 @@
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 @@
{
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)