bcache: check return value from btree_node_alloc_replacement()

In btree_gc_rewrite_node(), pointer 'n' is not checked after it returns
from btree_gc_rewrite_node(). There is potential possibility that 'n' is
a non NULL ERR_PTR(), referencing such error code is not permitted in
following code. Therefore a return value checking is necessary after 'n'
is back from btree_node_alloc_replacement().

Signed-off-by: Coly Li <colyli@suse.de>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc:  <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20231120052503.6122-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index ae5cbb5..de8d552 100644 (file)
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1532,6 +1532,8 @@ static int btree_gc_rewrite_node(struct btree *b, struct btree_op *op,
                return 0;
 
        n = btree_node_alloc_replacement(replace, NULL);
+       if (IS_ERR(n))
+               return 0;
 
        /* recheck reserve after allocating replacement node */
        if (btree_check_reserve(b, NULL)) {