From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45953 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751676AbcBNXPc (ORCPT ); Sun, 14 Feb 2016 18:15:32 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Du, Changbin" Subject: [PATCH 4.4 063/117] usb: hub: do not clear BOS field during reset device Date: Sun, 14 Feb 2016 14:21:40 -0800 Message-Id: <20160214222143.308371641@linuxfoundation.org> In-Reply-To: <20160214222141.393531627@linuxfoundation.org> References: <20160214222141.393531627@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Du, Changbin commit d8f00cd685f5c8e0def8593e520a7fef12c22407 upstream. In function usb_reset_and_verify_device, the old BOS descriptor may still be used before allocating a new one. (usb_unlocked_disable_lpm function uses it under the situation that it fails to disable lpm.) So we cannot set the udev->bos to NULL before that, just keep what it was. It will be overwrite when allocating a new one. Crash log: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: [] usb_enable_link_state+0x2d/0x2f0 Call Trace: [] ? usb_set_lpm_timeout+0x12b/0x140 [] usb_enable_lpm+0x81/0xa0 [] usb_disable_lpm+0xa8/0xc0 [] usb_unlocked_disable_lpm+0x2c/0x50 [] usb_reset_and_verify_device+0xc3/0x710 [] ? usb_sg_wait+0x13d/0x190 [] usb_reset_device+0x133/0x280 [] usb_stor_port_reset+0x61/0x70 [] usb_stor_invoke_transport+0x88/0x520 Signed-off-by: Du, Changbin Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -5386,7 +5386,6 @@ static int usb_reset_and_verify_device(s } bos = udev->bos; - udev->bos = NULL; for (i = 0; i < SET_CONFIG_TRIES; ++i) { @@ -5479,8 +5478,11 @@ done: usb_set_usb2_hardware_lpm(udev, 1); usb_unlocked_enable_lpm(udev); usb_enable_ltm(udev); - usb_release_bos_descriptor(udev); - udev->bos = bos; + /* release the new BOS descriptor allocated by hub_port_init() */ + if (udev->bos != bos) { + usb_release_bos_descriptor(udev); + udev->bos = bos; + } return 0; re_enumerate: