Commit b070f29a authored Jun 15, 2023 by Zheng Wang Committed by Greg Kroah-Hartman Aug 11, 2023

bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent



[ Upstream commit 80fca8a10b604afad6c14213fdfd816c4eda3ee4 ]

In some specific situations, the return value of __bch_btree_node_alloc
may be NULL. This may lead to a potential NULL pointer dereference in
caller function like a calling chain :
btree_split->bch_btree_node_alloc->__bch_btree_node_alloc.

Fix it by initializing the return value in __bch_btree_node_alloc.

Fixes: cafe5635 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@suse.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 38a6dd2b

drivers/md/bcache/btree.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -1137,10 +1137,12 @@ struct btree __bch_btree_node_alloc(struct cache_set c, struct btree_op *op,
		struct btree *parent)
		{
		BKEY_PADDED(key) k;
		struct btree *b = ERR_PTR(-EAGAIN);
		struct btree *b;

		mutex_lock(&c->bucket_lock);
		retry:
		/* return ERR_PTR(-EAGAIN) when it fails */
		b = ERR_PTR(-EAGAIN);
		if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, wait))
		goto err;