Return-Path: From: Dean Jenkins To: CC: , , , , Dean Jenkins Subject: [PATCH v2 8/8] Bluetooth: __l2cap_wait_ack() add defensive timeout Date: Tue, 23 Jun 2015 17:59:39 +0100 Message-ID: <1435078779-4436-9-git-send-email-Dean_Jenkins@mentor.com> In-Reply-To: <1435078779-4436-1-git-send-email-Dean_Jenkins@mentor.com> References: <1435078779-4436-1-git-send-email-Dean_Jenkins@mentor.com> MIME-Version: 1.0 Content-Type: text/plain List-ID: Add a timeout to prevent the do while loop running in an infinite loop. This ensures that the channel will be instructed to close within 10 seconds so prevents l2cap_sock_shutdown() getting stuck forever. Returns -ENOLINK when the timeout is reached. The channel will be subequently closed and not all data will be ACK'ed. Signed-off-by: Dean Jenkins --- include/net/bluetooth/l2cap.h | 1 + net/bluetooth/l2cap_sock.c | 12 +++++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 3dcad41..c98afc0 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -56,6 +56,7 @@ #define L2CAP_MOVE_TIMEOUT msecs_to_jiffies(4000) #define L2CAP_MOVE_ERTX_TIMEOUT msecs_to_jiffies(60000) #define L2CAP_WAIT_ACK_POLL_PERIOD msecs_to_jiffies(200) +#define L2CAP_WAIT_ACK_TIMEOUT msecs_to_jiffies(10000) #define L2CAP_A2MP_DEFAULT_MTU 670 diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 2c09ec1..f967749 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1059,11 +1059,16 @@ static int __l2cap_wait_ack(struct sock *sk, struct l2cap_chan *chan) DECLARE_WAITQUEUE(wait, current); int err = 0; int timeo = L2CAP_WAIT_ACK_POLL_PERIOD; + /* Timeout to prevent infinite loop */ + unsigned long timeout = jiffies + L2CAP_WAIT_ACK_TIMEOUT; add_wait_queue(sk_sleep(sk), &wait); set_current_state(TASK_INTERRUPTIBLE); do { - BT_DBG("Waiting for %d ACKs", chan->unacked_frames); + BT_DBG("Waiting for %d ACKs, timeout %04d ms", + chan->unacked_frames, + time_after(jiffies, timeout) ? 0 : + jiffies_to_msecs(timeout - jiffies)); if (!timeo) timeo = L2CAP_WAIT_ACK_POLL_PERIOD; @@ -1082,6 +1087,11 @@ static int __l2cap_wait_ack(struct sock *sk, struct l2cap_chan *chan) if (err) break; + if (time_after(jiffies, timeout)) { + err = -ENOLINK; + break; + } + } while (chan->unacked_frames > 0 && chan->state == BT_CONNECTED); -- 1.8.5.6