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 <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: David Decotigny <[email protected]>
Cc: Tom Herbert <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: Oliver Neukum <[email protected]>
Reviewed-by: Jiri Kosina <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Greg KH <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1775ad471edd..5480352f984d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -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);