[3.8.y.z extended stable] Patch "Bluetooth: Fix locking of hdev when calling into SMP code" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    Bluetooth: Fix locking of hdev when calling into SMP code

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.27.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From a335dc17d17644541fb38b9e4df1f8424103d612 Mon Sep 17 00:00:00 2001
From: Johan Hedberg <johan.hedberg at intel.com>
Date: Fri, 13 Jun 2014 10:22:28 +0300
Subject: Bluetooth: Fix locking of hdev when calling into SMP code

commit c73f94b8c093a615ce80eabbde0ac6eb9abfe31a upstream.

The SMP code expects hdev to be unlocked since e.g. crypto functions
will try to (re)lock it. Therefore, we need to release the lock before
calling into smp.c from mgmt.c. Without this we risk a deadlock whenever
the smp_user_confirm_reply() function is called.

Signed-off-by: Johan Hedberg <johan.hedberg at intel.com>
Tested-by: Lukasz Rymanowski <lukasz.rymanowski at tieto.com>
Signed-off-by: Marcel Holtmann <marcel at holtmann.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/bluetooth/mgmt.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index d8ba861..e470516 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -2048,8 +2048,13 @@ static int user_pairing_resp(struct sock *sk, struct hci_dev *hdev,
 	}

 	if (type == BDADDR_LE_PUBLIC || type == BDADDR_LE_RANDOM) {
-		/* Continue with pairing via SMP */
+		/* Continue with pairing via SMP. The hdev lock must be
+		 * released as SMP may try to recquire it for crypto
+		 * purposes.
+		 */
+		hci_dev_unlock(hdev);
 		err = smp_user_confirm_reply(conn, mgmt_op, passkey);
+		hci_dev_lock(hdev);

 		if (!err)
 			err = cmd_status(sk, hdev->id, mgmt_op,
--
1.9.1