[PATCH] Bluetooth: hci_core: Fix unbalanced unlock in set_device_flags()

* [PATCH] Bluetooth: hci_core: Fix unbalanced unlock in set_device_flags()
@ 2022-03-02 13:44 Hans de Goede
  2022-03-02 14:09 ` bluez.test.bot
  2022-03-02 14:21 ` [PATCH] " Marcel Holtmann
  0 siblings, 2 replies; 5+ messages in thread
From: Hans de Goede @ 2022-03-02 13:44 UTC (permalink / raw)
  To: Marcel Holtmann, Johan Hedberg, Luiz Augusto von Dentz
  Cc: Hans de Goede, linux-bluetooth, Luiz Augusto von Dentz

There is only one "goto done;" in set_device_flags() and this happens
*before* hci_dev_lock() is called, move the done label to after the
hci_dev_unlock() to fix the following unlock balance:

[   31.493567] =====================================
[   31.493571] WARNING: bad unlock balance detected!
[   31.493576] 5.17.0-rc2+ #13 Tainted: G         C  E
[   31.493581] -------------------------------------
[   31.493584] bluetoothd/685 is trying to release lock (&hdev->lock) at:
[   31.493594] [<ffffffffc07603f5>] set_device_flags+0x65/0x1f0 [bluetooth]
[   31.493684] but there are no more locks to release!

Note this bug has been around for a couple of years, but before
commit fe92ee6425a2 ("Bluetooth: hci_core: Rework hci_conn_params flags")
supported_flags was hardcoded to "((1U << HCI_CONN_FLAG_MAX) - 1)" so
the check for unsupported flags which does the "goto done;" never
triggered.

Fixes: fe92ee6425a2 ("Bluetooth: hci_core: Rework hci_conn_params flags")
Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 net/bluetooth/mgmt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 37087cf7dc5a..f05b9b73e84b 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -4513,9 +4513,9 @@ static int set_device_flags(struct sock *sk, struct hci_dev *hdev, void *data,
 		}
 	}
 
-done:
 	hci_dev_unlock(hdev);
 
+done:
 	if (status == MGMT_STATUS_SUCCESS)
 		device_flags_changed(sk, hdev, &cp->addr.bdaddr, cp->addr.type,
 				     supported_flags, current_flags);
-- 
2.35.1


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