4.20-stable review patch. If anyone has any objections, please let me know.
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From: Matthias Kaehlcke mka@chromium.org
commit c4f5627f7eeecde1bb6b646d8c0907b96dc2b2a6 upstream.
With commit e16337622016 ("Bluetooth: Handle bt_accept_enqueue() socket atomically") lock_sock[_nested]() is used to acquire the socket lock before manipulating the socket. lock_sock[_nested]() may block, which is problematic since bt_accept_enqueue() can be called in bottom half context (e.g. from rfcomm_connect_ind()):
[<ffffff80080d81ec>] __might_sleep+0x4c/0x80 [<ffffff800876c7b0>] lock_sock_nested+0x24/0x58 [<ffffff8000d7c27c>] bt_accept_enqueue+0x48/0xd4 [bluetooth] [<ffffff8000e67d8c>] rfcomm_connect_ind+0x190/0x218 [rfcomm]
Add a parameter to bt_accept_enqueue() to indicate whether the function is called from BH context, and acquire the socket lock with bh_lock_sock_nested() if that's the case.
Also adapt all callers of bt_accept_enqueue() to pass the new parameter:
- l2cap_sock_new_connection_cb() - uses lock_sock() to lock the parent socket => process context
- rfcomm_connect_ind() - acquires the parent socket lock with bh_lock_sock() => BH context
- __sco_chan_add() - called from sco_chan_add(), which is called from sco_connect(). parent is NULL, hence bt_accept_enqueue() isn't called in this code path and we can ignore it - also called from sco_conn_ready(). uses bh_lock_sock() to acquire the parent lock => BH context
Fixes: e16337622016 ("Bluetooth: Handle bt_accept_enqueue() socket atomically") Signed-off-by: Matthias Kaehlcke mka@chromium.org Reviewed-by: Douglas Anderson dianders@chromium.org Signed-off-by: Marcel Holtmann marcel@holtmann.org Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/net/bluetooth/bluetooth.h | 2 +- net/bluetooth/af_bluetooth.c | 16 +++++++++++++--- net/bluetooth/l2cap_sock.c | 2 +- net/bluetooth/rfcomm/sock.c | 2 +- net/bluetooth/sco.c | 2 +- 5 files changed, 17 insertions(+), 7 deletions(-)
--- a/include/net/bluetooth/bluetooth.h +++ b/include/net/bluetooth/bluetooth.h @@ -276,7 +276,7 @@ int bt_sock_ioctl(struct socket *sock, int bt_sock_wait_state(struct sock *sk, int state, unsigned long timeo); int bt_sock_wait_ready(struct sock *sk, unsigned long flags);
-void bt_accept_enqueue(struct sock *parent, struct sock *sk); +void bt_accept_enqueue(struct sock *parent, struct sock *sk, bool bh); void bt_accept_unlink(struct sock *sk); struct sock *bt_accept_dequeue(struct sock *parent, struct socket *newsock);
--- a/net/bluetooth/af_bluetooth.c +++ b/net/bluetooth/af_bluetooth.c @@ -154,15 +154,25 @@ void bt_sock_unlink(struct bt_sock_list } EXPORT_SYMBOL(bt_sock_unlink);
-void bt_accept_enqueue(struct sock *parent, struct sock *sk) +void bt_accept_enqueue(struct sock *parent, struct sock *sk, bool bh) { BT_DBG("parent %p, sk %p", parent, sk);
sock_hold(sk); - lock_sock_nested(sk, SINGLE_DEPTH_NESTING); + + if (bh) + bh_lock_sock_nested(sk); + else + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); + list_add_tail(&bt_sk(sk)->accept_q, &bt_sk(parent)->accept_q); bt_sk(sk)->parent = parent; - release_sock(sk); + + if (bh) + bh_unlock_sock(sk); + else + release_sock(sk); + parent->sk_ack_backlog++; } EXPORT_SYMBOL(bt_accept_enqueue); --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1252,7 +1252,7 @@ static struct l2cap_chan *l2cap_sock_new
l2cap_sock_init(sk, parent);
- bt_accept_enqueue(parent, sk); + bt_accept_enqueue(parent, sk, false);
release_sock(parent);
--- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -988,7 +988,7 @@ int rfcomm_connect_ind(struct rfcomm_ses rfcomm_pi(sk)->channel = channel;
sk->sk_state = BT_CONFIG; - bt_accept_enqueue(parent, sk); + bt_accept_enqueue(parent, sk, true);
/* Accept connection and return socket DLC */ *d = rfcomm_pi(sk)->dlc; --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -193,7 +193,7 @@ static void __sco_chan_add(struct sco_co conn->sk = sk;
if (parent) - bt_accept_enqueue(parent, sk); + bt_accept_enqueue(parent, sk, true); }
static int sco_chan_add(struct sco_conn *conn, struct sock *sk,