Patch "staging: gdm724x: gdm_mux: fix use-after-free on module unload" has been added to the 4.4-stable tree

Patch "staging: gdm724x: gdm_mux: fix use-after-free on module unload" has been added to the 4.4-stable tree

[gregkh]

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

    staging: gdm724x: gdm_mux: fix use-after-free on module unload

to the 4.4-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:
     staging-gdm724x-gdm_mux-fix-use-after-free-on-module-unload.patch
and it can be found in the queue-4.4 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 b58f45c8fc301fe83ee28cad3e64686c19e78f1c Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 26 Apr 2017 12:23:04 +0200
Subject: staging: gdm724x: gdm_mux: fix use-after-free on module unload

From: Johan Hovold <johan@kernel.org>

commit b58f45c8fc301fe83ee28cad3e64686c19e78f1c upstream.

Make sure to deregister the USB driver before releasing the tty driver
to avoid use-after-free in the USB disconnect callback where the tty
devices are deregistered.

Fixes: 61e121047645 ("staging: gdm7240: adding LTE USB driver")
Cc: Won Kang <wkang77@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/gdm724x/gdm_mux.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/staging/gdm724x/gdm_mux.c
+++ b/drivers/staging/gdm724x/gdm_mux.c
@@ -670,14 +670,14 @@ static int __init gdm_usb_mux_init(void)
 
 static void __exit gdm_usb_mux_exit(void)
 {
-	unregister_lte_tty_driver();
-
 	if (mux_rx_wq) {
 		flush_workqueue(mux_rx_wq);
 		destroy_workqueue(mux_rx_wq);
 	}
 
 	usb_deregister(&gdm_mux_driver);
+	unregister_lte_tty_driver();
+
 }
 
 module_init(gdm_usb_mux_init);


Patches currently in stable-queue which might be from johan@kernel.org are

queue-4.4/usb-serial-ftdi_sio-add-device-id-for-microsemi-arrow-sf2plus-dev-kit.patch
queue-4.4/staging-gdm724x-gdm_mux-fix-use-after-free-on-module-unload.patch