From: Zheng Wang <zyytlz.wz@xxxxxxx>
commit 80fca8a10b604afad6c14213fdfd816c4eda3ee4 upstream.
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: cafe56359144 ("bcache: A block layer cache")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
Signed-off-by: Coly Li <colyli@xxxxxxx>
Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@xxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/bcache/btree.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1090,10 +1090,12 @@ struct btree *__bch_btree_node_alloc(str
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;
