From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754368AbdLGSCg (ORCPT ); Thu, 7 Dec 2017 13:02:36 -0500 Received: from fldsmtpe03.verizon.com ([140.108.26.142]:60675 "EHLO fldsmtpe03.verizon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755841AbdLGPse (ORCPT ); Thu, 7 Dec 2017 10:48:34 -0500 From: alexander.levin@verizon.com Cc: =?utf-8?B?Um9uYWxkIFRzY2hhbMOkcg==?= , "Marcel Holtmann" , alexander.levin@verizon.com X-Host: surveyor.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.14 061/135] Bluetooth: hci_ldisc: Fix another race when closing the tty. Thread-Topic: [PATCH AUTOSEL for 4.14 061/135] Bluetooth: hci_ldisc: Fix another race when closing the tty. Thread-Index: AQHTb3JxHAFUGjfVC0mt9pzfsRAnLg== Date: Thu, 7 Dec 2017 15:45:45 +0000 Message-ID: <20171207154513.4154-61-alexander.levin@verizon.com> References: <20171207154513.4154-1-alexander.levin@verizon.com> In-Reply-To: <20171207154513.4154-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="utf-8" Content-ID: MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id vB7I2fmB011974 From: Ronald Tschalär [ Upstream commit 0338b1b393ec7910898e8f7b25b3bf31a7282e16 ] The following race condition still existed: P1 P2 cancel_work_sync() hci_uart_tx_wakeup() hci_uart_write_work() hci_uart_dequeue() clear_bit(HCI_UART_PROTO_READY) hci_unregister_dev(hdev) hci_free_dev(hdev) hu->proto->close(hu) kfree(hu) access to hdev and hu Cancelling the work after clearing the HCI_UART_PROTO_READY bit avoids this as any hci_uart_tx_wakeup() issued after the flag is cleared will detect that and not schedule further work. Signed-off-by: Ronald Tschalär Reviewed-by: Lukas Wunner Signed-off-by: Marcel Holtmann Signed-off-by: Sasha Levin --- drivers/bluetooth/hci_ldisc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index a746627e784e..6e2403805784 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -510,13 +510,13 @@ static void hci_uart_tty_close(struct tty_struct *tty) if (hdev) hci_uart_close(hdev); - cancel_work_sync(&hu->write_work); - if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) { write_lock_irqsave(&hu->proto_lock, flags); clear_bit(HCI_UART_PROTO_READY, &hu->flags); write_unlock_irqrestore(&hu->proto_lock, flags); + cancel_work_sync(&hu->write_work); + if (hdev) { if (test_bit(HCI_UART_REGISTERED, &hu->flags)) hci_unregister_dev(hdev); -- 2.11.0