Bluetooth: L2CAP: Fix invalid access if ECRED Reconfigure fails

The use of l2cap_chan_del is not safe under a loop using
list_for_each_entry.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap_core.c

@@ -6248,7 +6248,7 @@ static inline int l2cap_ecred_reconf_rsp(struct l2cap_conn *conn,
 					 struct l2cap_cmd_hdr *cmd, u16 cmd_len,
 					 u8 *data)
 {
-	struct l2cap_chan *chan;
+	struct l2cap_chan *chan, *tmp;
 	struct l2cap_ecred_conn_rsp *rsp = (void *) data;
 	u16 result;
 
@@ -6262,7 +6262,7 @@ static inline int l2cap_ecred_reconf_rsp(struct l2cap_conn *conn,
 	if (!result)
 		return 0;
 
-	list_for_each_entry(chan, &conn->chan_l, list) {
+	list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {
 		if (chan->ident != cmd->ident)
 			continue;