Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755329AbaK0Ixs (ORCPT ); Thu, 27 Nov 2014 03:53:48 -0500 Received: from mail.kernel.org ([198.145.19.201]:42867 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752756AbaK0It7 (ORCPT ); Thu, 27 Nov 2014 03:49:59 -0500 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Felipe Balbi , Greg Kroah-Hartman , Tim Niemeyer , Zefan Li Subject: [PATCH 3.4 80/91] bluetooth: hci_ldisc: fix deadlock condition Date: Thu, 27 Nov 2014 16:43:03 +0800 Message-Id: <1417077794-9299-80-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1417077368-9217-1-git-send-email-lizf@kernel.org> References: <1417077368-9217-1-git-send-email-lizf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Felipe Balbi 3.4.105-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit da64c27d3c93ee9f89956b9de86c4127eb244494 upstream. LDISCs shouldn't call tty->ops->write() from within ->write_wakeup(). ->write_wakeup() is called with port lock taken and IRQs disabled, tty->ops->write() will try to acquire the same port lock and we will deadlock. Acked-by: Marcel Holtmann Reviewed-by: Peter Hurley Reported-by: Huang Shijie Signed-off-by: Felipe Balbi Tested-by: Andreas Bießmann Signed-off-by: Greg Kroah-Hartman [tim.niemeyer@corscience.de: rebased on 3.4.103] Signed-off-by: Tim Niemeyer Signed-off-by: Zefan Li --- drivers/bluetooth/hci_ldisc.c | 25 ++++++++++++++++++++----- drivers/bluetooth/hci_uart.h | 2 ++ 2 files changed, 22 insertions(+), 5 deletions(-) diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index 98a8c05..d4550f9 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -118,10 +118,6 @@ static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu) int hci_uart_tx_wakeup(struct hci_uart *hu) { - struct tty_struct *tty = hu->tty; - struct hci_dev *hdev = hu->hdev; - struct sk_buff *skb; - if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) { set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state); return 0; @@ -129,6 +125,22 @@ int hci_uart_tx_wakeup(struct hci_uart *hu) BT_DBG(""); + schedule_work(&hu->write_work); + + return 0; +} + +static void hci_uart_write_work(struct work_struct *work) +{ + struct hci_uart *hu = container_of(work, struct hci_uart, write_work); + struct tty_struct *tty = hu->tty; + struct hci_dev *hdev = hu->hdev; + struct sk_buff *skb; + + /* REVISIT: should we cope with bad skbs or ->write() returning + * and error value ? + */ + restart: clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state); @@ -153,7 +165,6 @@ restart: goto restart; clear_bit(HCI_UART_SENDING, &hu->tx_state); - return 0; } /* ------- Interface to HCI layer ------ */ @@ -264,6 +275,8 @@ static int hci_uart_tty_open(struct tty_struct *tty) hu->tty = tty; tty->receive_room = 65536; + INIT_WORK(&hu->write_work, hci_uart_write_work); + spin_lock_init(&hu->rx_lock); /* Flush any pending characters in the driver and line discipline. */ @@ -298,6 +311,8 @@ static void hci_uart_tty_close(struct tty_struct *tty) if (hdev) hci_uart_close(hdev); + cancel_work_sync(&hu->write_work); + if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) { if (hdev) { hci_unregister_dev(hdev); diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h index 6cf6ab22..af93d83 100644 --- a/drivers/bluetooth/hci_uart.h +++ b/drivers/bluetooth/hci_uart.h @@ -66,6 +66,8 @@ struct hci_uart { unsigned long flags; unsigned long hdev_flags; + struct work_struct write_work; + struct hci_uart_proto *proto; void *priv; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/