usb: forbid memory allocation with I/O during bus reset
Ming Lei [Sat, 23 Feb 2013 00:34:22 +0000 (16:34 -0800)]
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>

drivers/usb/core/hub.c

index 1775ad4..5480352 100644 (file)
@@ -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);