On Sat, Feb 18, 2023 at 03:23:35PM +0800, Zheng Wang wrote:

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

Fix it by initialize return value in __bch_btree_node_alloc before return.

Fixes: cafe56359144 ("bcache: A block layer cache") Cc: stable@vger.kernel.org Signed-off-by: Zheng Wang zyytlz.wz@163.com

Thanks, I will add this series to my for-next testing queue.

Coly Li

---

v3:

• Add Cc: stable@vger.kernel.org suggested by Eric

v2:

• split patch v1 into two patches to make it clearer suggested by Coly Li

---

drivers/md/bcache/btree.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 147c493a989a..cae25e74b9e0 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -1090,10 +1090,12 @@ 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;

-- 2.25.1