Commit 77ef6c4d authored by Pete Zaitcev's avatar Pete Zaitcev Committed by Greg Kroah-Hartman
Browse files

[PATCH] USB: ub oops in block_uevent 



In kernel 2.6.16, if a mounted storage device is removed, an oops happens
because ub supplies an interface device (and kobject) to the block layer,
but neglects to pin it. And apparently, the block layer expects its users
to pin device structures.

The code in ub was broken this way for years. But the bug was exposed only
by 2.6.16 when it started to call block_uevent on close, which traverses
device structures (kobjects actually).

Signed-off-by: default avatarPete Zaitcev <zaitcev@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 436f5762

drivers/block/ub.c

+10 −8
Original line number Diff line number Diff line
@@ -536,6 +536,9 @@ static void ub_cleanup(struct ub_dev *sc) 
		kfree(lun);

	}



	usb_set_intfdata(sc->intf, NULL);

	usb_put_intf(sc->intf);

	usb_put_dev(sc->dev);

	kfree(sc);

}
@@ -2221,7 +2224,12 @@ static int ub_probe(struct usb_interface *intf, 
	// sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;

	usb_set_intfdata(intf, sc);

	usb_get_dev(sc->dev);

	// usb_get_intf(sc->intf);	/* Do we need this? */

	/*

	 * Since we give the interface struct to the block level through

	 * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent

	 * oopses on close after a disconnect (kernels 2.6.16 and up).

	 */

	usb_get_intf(sc->intf);



	snprintf(sc->name, 12, DRV_NAME "(%d.%d)",

	    sc->dev->bus->busnum, sc->dev->devnum);
@@ -2286,7 +2294,7 @@ static int ub_probe(struct usb_interface *intf, 


err_dev_desc:

	usb_set_intfdata(intf, NULL);

	// usb_put_intf(sc->intf);

	usb_put_intf(sc->intf);

	usb_put_dev(sc->dev);

	kfree(sc);

err_core:
@@ -2461,12 +2469,6 @@ static void ub_disconnect(struct usb_interface *intf) 
	 * and no URBs left in transit.

	 */



	usb_set_intfdata(intf, NULL);

	// usb_put_intf(sc->intf);

	sc->intf = NULL;

	usb_put_dev(sc->dev);

	sc->dev = NULL;



	ub_put(sc);

}

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