bluetooth: fix list handling

Commit 835a6a2f8603 ("Bluetooth: Stop sabotaging list poisoning")
thought that the code was sabotaging the list poisoning when NULL'ing
out the list pointers and removed it.

But what was going on was that the bluetooth code was using NULL
pointers for the list as a way to mark it empty, and that commit just
broke it (and replaced the test with NULL with a "list_empty()" test on
a uninitialized list instead, breaking things even further).

So fix it all up to use the regular and real list_empty() handling
(which does not use NULL, but a pointer to itself), also making sure to
initialize the list properly (the previous NULL case was initialized
implicitly by the session being allocated with kzalloc())

This is a combination of patches by Marcel Holtmann and Tedd Ho-Jeong
An.

[ I would normally expect to get this through the bt tree, but I'm going
  to release -rc1, so I'm just committing this directly   - Linus ]

Reported-and-tested-by: Jörg Otte <jrg.otte@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Original-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Original-by: Marcel Holtmann <marcel@holtmann.org>:
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 9070dfd6b4adcd247c482589c27d5d4519302b7c..f1a117f8cad22a245044014eae118e09bcdfe271 100644 (file)
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -915,6 +915,7 @@ static int hidp_session_new(struct hidp_session **out, const bdaddr_t *bdaddr,
        session->conn = l2cap_conn_get(conn);
        session->user.probe = hidp_session_probe;
        session->user.remove = hidp_session_remove;
+       INIT_LIST_HEAD(&session->user.list);
        session->ctrl_sock = ctrl_sock;
        session->intr_sock = intr_sock;
        skb_queue_head_init(&session->ctrl_transmit);

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 51594fb7b9e72f80c06af1f04e9fd89b01aba9ba..45fffa4136421b8dd5ab301cf0a4ec529b36ff8e 100644 (file)
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1634,7 +1634,7 @@ void l2cap_unregister_user(struct l2cap_conn *conn, struct l2cap_user *user)
        if (list_empty(&user->list))
                goto out_unlock;
 
-       list_del(&user->list);
+       list_del_init(&user->list);
        user->remove(conn, user);
 
 out_unlock:
@@ -1648,7 +1648,7 @@ static void l2cap_unregister_all_users(struct l2cap_conn *conn)
 
        while (!list_empty(&conn->users)) {
                user = list_first_entry(&conn->users, struct l2cap_user, list);
-               list_del(&user->list);
+               list_del_init(&user->list);
                user->remove(conn, user);
        }
 }