From: David Miller <davem@davemloft.net>
Date: Thu, 17 Dec 2015 21:05:49 +0000 (-0500)
Subject: mkiss: Fix use after free in mkiss_close().
X-Git-Tag: v4.4-rc8~5^2~24
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d79f16c046086f4fe0d42184a458e187464eb83e;p=platform%2Fkernel%2Flinux-exynos.git

mkiss: Fix use after free in mkiss_close().

Need to do the unregister_device() after all references to the driver
private have been done.

Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index 216bfd3..0b72b9d 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -798,13 +798,13 @@ static void mkiss_close(struct tty_struct *tty)
 	if (!atomic_dec_and_test(&ax->refcnt))
 		down(&ax->dead_sem);
 
-	unregister_netdev(ax->dev);
-
 	/* Free all AX25 frame buffers. */
 	kfree(ax->rbuff);
 	kfree(ax->xbuff);
 
 	ax->tty = NULL;
+
+	unregister_netdev(ax->dev);
 }
 
 /* Perform I/O control on an active ax25 channel. */