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Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating

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The usage of rcu_read_(un)lock while inside list_for_each_entry_rcu is
not safe since for the most part entries fetched this way shall be
treated as rcu_dereference:

	Note that the value returned by rcu_dereference() is valid
	only within the enclosing RCU read-side critical section [1]_.
	For example, the following is **not** legal::

		rcu_read_lock();
		p = rcu_dereference(head.next);
		rcu_read_unlock();
		x = p->address;	/* BUG!!! */
		rcu_read_lock();
		y = p->data;	/* BUG!!! */
		rcu_read_unlock();

Fixes: a0bfde167b ("Bluetooth: ISO: Add support for connecting multiple BISes")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Luiz Augusto von Dentz 2024-12-04 11:40:59 -05:00
parent 4d94f05558
commit 581dd2dc16
1 changed files with 11 additions and 22 deletions
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33
net/bluetooth/hci_event.c
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@ -6870,38 +6870,27 @@ static void hci_le_create_big_complete_evt(struct hci_dev *hdev, void *data,
return;
hci_dev_lock(hdev);
rcu_read_lock();
/* Connect all BISes that are bound to the BIG */
list_for_each_entry_rcu(conn, &hdev->conn_hash.list, list) {
if (bacmp(&conn->dst, BDADDR_ANY) ||
conn->type != ISO_LINK ||
conn->iso_qos.bcast.big != ev->handle)
while ((conn = hci_conn_hash_lookup_big_state(hdev, ev->handle,
BT_BOUND))) {
if (ev->status) {
hci_connect_cfm(conn, ev->status);
hci_conn_del(conn);
continue;
}
if (hci_conn_set_handle(conn,
__le16_to_cpu(ev->bis_handle[i++])))
continue;
if (!ev->status) {
conn->state = BT_CONNECTED;
set_bit(HCI_CONN_BIG_CREATED, &conn->flags);
rcu_read_unlock();
hci_debugfs_create_conn(conn);
hci_conn_add_sysfs(conn);
hci_iso_setup_path(conn);
rcu_read_lock();
continue;
}
hci_connect_cfm(conn, ev->status);
rcu_read_unlock();
hci_conn_del(conn);
rcu_read_lock();
conn->state = BT_CONNECTED;
set_bit(HCI_CONN_BIG_CREATED, &conn->flags);
hci_debugfs_create_conn(conn);
hci_conn_add_sysfs(conn);
hci_iso_setup_path(conn);
}
rcu_read_unlock();
if (!ev->status && !i)
/* If no BISes have been connected for the BIG,
* terminate. This is in case all bound connections