diff options
| author | Myungho Jung <mhjungk@gmail.com> | 2019-02-02 16:56:36 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-27 14:13:03 +0900 |
| commit | bd140b032555615d48c58a13f7f53e2ae1a6327b (patch) | |
| tree | 42650797dc0124de337ecf84a85579d9a50d2ca9 | |
| parent | d54a396379ba57f813f4bbcafefd5c3ea740facd (diff) | |
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: Myungho Jung <mhjungk@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/bluetooth/hci_sock.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c index c88a6007e643..ca1836941f3c 100644 --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -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 an user channel exclusive access, |