bcache: Fix a null ptr deref in journal replay

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index e38c5997bf12706afa0e649bd96e80d284a9a758..97e6a92da9999f1b25e8c8fb6a30315932b17584 100644 (file)
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -287,9 +287,13 @@ void bch_journal_mark(struct cache_set *c, struct list_head *list)
                     k < bset_bkey_last(&i->j);
                     k = bkey_next(k)) {
                        unsigned j;
+                       struct bucket *g;
 
                        for (j = 0; j < KEY_PTRS(k); j++) {
-                               struct bucket *g = PTR_BUCKET(c, k, j);
+                               if (!ptr_available(c, k, j))
+                                       continue;
+
+                               g = PTR_BUCKET(c, k, j);
                                atomic_inc(&g->pin);
 
                                if (g->prio == BTREE_PRIO &&