Fix possible NULL pointer dereference in dbuf_verify()

Coverity reported a dereference after a NULL check in dbuf_verify(). If `dn` is `NULL`, we can just assume that !dn->dn_free_txg, so we change `!dn->dn_free_txg` to `(dn == NULL || !dn->dn_free_txg)`. Reviewed-by: Tino Reichardt <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Richard Yao <[email protected]> Reported-by: Coverity (CID-992298) Closes openzfs#14619
rrevans · Mar 14, 2023 · 3cb293a · 3cb293a
1 parent 3a03c96
commit 3cb293a
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
@@ -1157,7 +1157,7 @@ dbuf_verify(dmu_buf_impl_t *db)
 	if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
 	    (db->db_buf == NULL || db->db_buf->b_data) &&
 	    db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
-	    db->db_state != DB_FILL && !dn->dn_free_txg) {
+	    db->db_state != DB_FILL && (dn == NULL || !dn->dn_free_txg)) {
 		/*
 		 * If the blkptr isn't set but they have nonzero data,
 		 * it had better be dirty, otherwise we'll lose that