Commit 4d769def authored Feb 22, 2013 by Ming Lei Committed by Linus Torvalds Feb 23, 2013

usb: forbid memory allocation with I/O during bus reset



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).

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Decotigny <david.decotigny@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oneukum@suse.de>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent db88175f

drivers/usb/core/hub.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -5177,6 +5177,7 @@ 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 \|\|
		@@ -5186,6 +5187,17 @@ 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.
		*/
		noio_flag = memalloc_noio_save();

		/* Prevent autosuspend during the reset */
		usb_autoresume_device(udev);

		@@ -5230,6 +5242,7 @@ 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);