From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754423Ab2KCIhY (ORCPT ); Sat, 3 Nov 2012 04:37:24 -0400 Received: from mail-da0-f46.google.com ([209.85.210.46]:47415 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754120Ab2KCIhR (ORCPT ); Sat, 3 Nov 2012 04:37:17 -0400 From: Ming Lei To: linux-kernel@vger.kernel.org Cc: Alan Stern , Oliver Neukum , Minchan Kim , Greg Kroah-Hartman , "Rafael J. Wysocki" , Jens Axboe , "David S. Miller" , Andrew Morton , netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-pm@vger.kernel.org, linux-mm@kvack.org, Ming Lei Subject: [PATCH v4 6/6] USB: forbid memory allocation with I/O during bus reset Date: Sat, 3 Nov 2012 16:35:14 +0800 Message-Id: <1351931714-11689-7-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1351931714-11689-1-git-send-email-ming.lei@canonical.com> References: <1351931714-11689-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If one storage interface or usb network interface(iSCSI case) exists in current configuration, memory allocation with GFP_KERNEL during usb_device_reset() might trigger I/O transfer on the storage interface itself and cause deadlock because the 'us->dev_mutex' is held in .pre_reset() and the storage interface can't do I/O transfer when the reset is triggered by other interface, or the error handling can't be completed if the reset is triggered by the storage itself(error handling path). Cc: Alan Stern Cc: Oliver Neukum Signed-off-by: Ming Lei --- v4: - mark current memalloc_noio for every usb device reset --- drivers/usb/core/hub.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 5b131b6..788e652 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -5044,6 +5044,7 @@ int usb_reset_device(struct usb_device *udev) { int ret; int i; + unsigned int noio_flag; struct usb_host_config *config = udev->actconfig; if (udev->state == USB_STATE_NOTATTACHED || @@ -5053,6 +5054,17 @@ int usb_reset_device(struct usb_device *udev) return -EINVAL; } + /* + * Don't allocate memory with GFP_KERNEL in current + * context to avoid possible deadlock if usb mass + * storage interface or usbnet interface(iSCSI case) + * is included in current configuration. The easist + * approach is to do it for every device reset, + * because the device 'memalloc_noio' flag may have + * not been set before reseting the usb device. + */ + memalloc_noio_save(noio_flag); + /* Prevent autosuspend during the reset */ usb_autoresume_device(udev); @@ -5097,6 +5109,7 @@ int usb_reset_device(struct usb_device *udev) } usb_autosuspend_device(udev); + memalloc_noio_restore(noio_flag); return ret; } EXPORT_SYMBOL_GPL(usb_reset_device); -- 1.7.9.5