From patchwork Thu Mar 20 19:30:05 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Felipe Balbi X-Patchwork-Id: 3867591 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id F2BE6BF540 for ; Thu, 20 Mar 2014 19:35:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 29F0A201BF for ; Thu, 20 Mar 2014 19:35:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42DEE2010E for ; Thu, 20 Mar 2014 19:35:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964925AbaCTTcL (ORCPT ); Thu, 20 Mar 2014 15:32:11 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:57366 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965088AbaCTTcG (ORCPT ); Thu, 20 Mar 2014 15:32:06 -0400 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by comal.ext.ti.com (8.13.7/8.13.7) with ESMTP id s2KJW4sl012251; Thu, 20 Mar 2014 14:32:04 -0500 Received: from DLEE71.ent.ti.com (dlee71.ent.ti.com [157.170.170.114]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id s2KJW3O7018057; Thu, 20 Mar 2014 14:32:03 -0500 Received: from dflp32.itg.ti.com (10.64.6.15) by DLEE71.ent.ti.com (157.170.170.114) with Microsoft SMTP Server id 14.3.174.1; Thu, 20 Mar 2014 14:32:03 -0500 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp32.itg.ti.com (8.14.3/8.13.8) with ESMTP id s2KJW3LA031085; Thu, 20 Mar 2014 14:32:03 -0500 From: Felipe Balbi To: Greg KH CC: , , , , , Linux OMAP Mailing List , Linux Kernel Mailing List , Felipe Balbi Subject: [PATCH 09/11] bluetooth: hci_ldisc: fix deadlock condition Date: Thu, 20 Mar 2014 14:30:05 -0500 Message-ID: <1395343807-21618-9-git-send-email-balbi@ti.com> X-Mailer: git-send-email 1.9.1.286.g5172cb3 In-Reply-To: <1395343807-21618-1-git-send-email-balbi@ti.com> References: <1395343807-21618-1-git-send-email-balbi@ti.com> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. Reviewed-by: Peter Hurley Reported-by: Huang Shijie Signed-off-by: Felipe Balbi Acked-by: Marcel Holtmann --- drivers/bluetooth/hci_ldisc.c | 24 +++++++++++++++++++----- drivers/bluetooth/hci_uart.h | 1 + 2 files changed, 20 insertions(+), 5 deletions(-) diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index 6e06f6f..77af52f 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; } static void hci_uart_init_work(struct work_struct *work) @@ -281,6 +292,7 @@ static int hci_uart_tty_open(struct tty_struct *tty) tty->receive_room = 65536; INIT_WORK(&hu->init_ready, hci_uart_init_work); + INIT_WORK(&hu->write_work, hci_uart_write_work); spin_lock_init(&hu->rx_lock); @@ -318,6 +330,8 @@ 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) { if (test_bit(HCI_UART_REGISTERED, &hu->flags)) diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h index fffa61f..12df101 100644 --- a/drivers/bluetooth/hci_uart.h +++ b/drivers/bluetooth/hci_uart.h @@ -68,6 +68,7 @@ struct hci_uart { unsigned long hdev_flags; struct work_struct init_ready; + struct work_struct write_work; struct hci_uart_proto *proto; void *priv;