Patch "usb: misc: lvs: fix race condition in disconnect handling" has been added to the 4.9-stable tree

Patch "usb: misc: lvs: fix race condition in disconnect handling" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    usb: misc: lvs: fix race condition in disconnect handling

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-misc-lvs-fix-race-condition-in-disconnect-handling.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Sun Mar 18 16:55:33 CET 2018
From: Oliver Neukum <oneukum@suse.com>
Date: Tue, 14 Mar 2017 12:05:07 +0100
Subject: usb: misc: lvs: fix race condition in disconnect handling

From: Oliver Neukum <oneukum@suse.com>


[ Upstream commit c4ba329cabca7c839ab48fb58b5bcc2582951a48 ]

There is a small window during which the an URB may
remain active after disconnect has returned. If in that case
already freed memory may be accessed and executed.

The fix is to poison the URB befotre the work is flushed.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/misc/lvstest.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/usb/misc/lvstest.c
+++ b/drivers/usb/misc/lvstest.c
@@ -433,6 +433,7 @@ static void lvs_rh_disconnect(struct usb
 	struct lvs_rh *lvs = usb_get_intfdata(intf);
 
 	sysfs_remove_group(&intf->dev.kobj, &lvs_attr_group);
+	usb_poison_urb(lvs->urb); /* used in scheduled work */
 	flush_work(&lvs->rh_work);
 	usb_free_urb(lvs->urb);
 }


Patches currently in stable-queue which might be from oneukum@suse.com are

queue-4.9/usb-misc-lvs-fix-race-condition-in-disconnect-handling.patch