Commit 3df00eb8 authored by Myungho Jung's avatar Myungho Jung Committed by Greg Kroah-Hartman

Bluetooth: Fix decrementing reference count twice in releasing socket

commit e20a2e9c42c9e4002d9e338d74e7819e88d77162 upstream.

When releasing socket, it is possible to enter hci_sock_release() and
hci_sock_dev_event(HCI_DEV_UNREG) at the same time in different thread.
The reference count of hdev should be decremented only once from one of
them but if storing hdev to local variable in hci_sock_release() before
detached from socket and setting to NULL in hci_sock_dev_event(),
hci_dev_put(hdev) is unexpectedly called twice. This is resolved by
referencing hdev from socket after bt_sock_unlink() in
hci_sock_release().

Reported-by: syzbot+fdc00003f4efff43bc5b@syzkaller.appspotmail.com
Signed-off-by: 's avatarMyungho Jung <mhjungk@gmail.com>
Signed-off-by: 's avatarMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 86384a1f
......@@ -826,8 +826,6 @@ static int hci_sock_release(struct socket *sock)
if (!sk)
return 0;
hdev = hci_pi(sk)->hdev;
switch (hci_pi(sk)->channel) {
case HCI_CHANNEL_MONITOR:
atomic_dec(&monitor_promisc);
......@@ -849,6 +847,7 @@ static int hci_sock_release(struct socket *sock)
bt_sock_unlink(&hci_sk_list, sk);
hdev = hci_pi(sk)->hdev;
if (hdev) {
if (hci_pi(sk)->channel == HCI_CHANNEL_USER) {
/* When releasing a user channel exclusive access,
......
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