[Bluetooth] Fix deadlock in the L2CAP layer

The Bluetooth L2CAP layer has 2 locks that are used in softirq context,
(one spinlock and one rwlock, where the softirq usage is readlock) but
where not all usages of the lock were _bh safe. The patch below corrects
this.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index eaaad658d11dcd34db3e606d6c2e58d5929cd73c..d56f60b392ac512b36a736f928844208ec88847a 100644 (file)
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -185,7 +185,7 @@ static inline void l2cap_chan_unlink(struct l2cap_chan_list *l, struct sock *sk)
 {
        struct sock *next = l2cap_pi(sk)->next_c, *prev = l2cap_pi(sk)->prev_c;
 
-       write_lock(&l->lock);
+       write_lock_bh(&l->lock);
        if (sk == l->head)
                l->head = next;
 
@@ -193,7 +193,7 @@ static inline void l2cap_chan_unlink(struct l2cap_chan_list *l, struct sock *sk)
                l2cap_pi(next)->prev_c = prev;
        if (prev)
                l2cap_pi(prev)->next_c = next;
-       write_unlock(&l->lock);
+       write_unlock_bh(&l->lock);
 
        __sock_put(sk);
 }
@@ -313,9 +313,9 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
 static inline void l2cap_chan_add(struct l2cap_conn *conn, struct sock *sk, struct sock *parent)
 {
        struct l2cap_chan_list *l = &conn->chan_list;
-       write_lock(&l->lock);
+       write_lock_bh(&l->lock);
        __l2cap_chan_add(conn, sk, parent);
-       write_unlock(&l->lock);
+       write_unlock_bh(&l->lock);
 }
 
 static inline u8 l2cap_get_ident(struct l2cap_conn *conn)
@@ -328,14 +328,14 @@ static inline u8 l2cap_get_ident(struct l2cap_conn *conn)
         *  200 - 254 are used by utilities like l2ping, etc.
         */
 
-       spin_lock(&conn->lock);
+       spin_lock_bh(&conn->lock);
 
        if (++conn->tx_ident > 128)
                conn->tx_ident = 1;
 
        id = conn->tx_ident;
 
-       spin_unlock(&conn->lock);
+       spin_unlock_bh(&conn->lock);
 
        return id;
 }
@@ -1416,11 +1416,11 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
        if (!sk)
                goto response;
 
-       write_lock(&list->lock);
+       write_lock_bh(&list->lock);
 
        /* Check if we already have channel with that dcid */
        if (__l2cap_get_chan_by_dcid(list, scid)) {
-               write_unlock(&list->lock);
+               write_unlock_bh(&list->lock);
                sock_set_flag(sk, SOCK_ZAPPED);
                l2cap_sock_kill(sk);
                goto response;
@@ -1458,7 +1458,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
        result = status = 0;
 
 done:
-       write_unlock(&list->lock);
+       write_unlock_bh(&list->lock);
 
 response:
        bh_unlock_sock(parent);