Patch "can: peak: fix bad memory access and free sequence" has been added to the 4.4-stable tree

Patch "can: peak: fix bad memory access and free sequence" 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

    can: peak: fix bad memory access and free sequence

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:
     can-peak-fix-bad-memory-access-and-free-sequence.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 b67d0dd7d0dc9e456825447bbeb935d8ef43ea7c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EC=B6=94=EC=A7=80=ED=98=B8?= <jiho.chu@samsung.com>
Date: Thu, 8 Dec 2016 12:01:13 +0000
Subject: can: peak: fix bad memory access and free sequence

From: 추지호 <jiho.chu@samsung.com>

commit b67d0dd7d0dc9e456825447bbeb935d8ef43ea7c upstream.

Fix for bad memory access while disconnecting. netdev is freed before
private data free, and dev is accessed after freeing netdev.

This makes a slub problem, and it raise kernel oops with slub debugger
config.

Signed-off-by: Jiho Chu <jiho.chu@samsung.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/can/usb/peak_usb/pcan_usb_core.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -872,23 +872,25 @@ lbl_free_candev:
 static void peak_usb_disconnect(struct usb_interface *intf)
 {
 	struct peak_usb_device *dev;
+	struct peak_usb_device *dev_prev_siblings;
 
 	/* unregister as many netdev devices as siblings */
-	for (dev = usb_get_intfdata(intf); dev; dev = dev->prev_siblings) {
+	for (dev = usb_get_intfdata(intf); dev; dev = dev_prev_siblings) {
 		struct net_device *netdev = dev->netdev;
 		char name[IFNAMSIZ];
 
+		dev_prev_siblings = dev->prev_siblings;
 		dev->state &= ~PCAN_USB_STATE_CONNECTED;
 		strncpy(name, netdev->name, IFNAMSIZ);
 
 		unregister_netdev(netdev);
-		free_candev(netdev);
 
 		kfree(dev->cmd_buf);
 		dev->next_siblings = NULL;
 		if (dev->adapter->dev_free)
 			dev->adapter->dev_free(dev);
 
+		free_candev(netdev);
 		dev_info(&intf->dev, "%s removed\n", name);
 	}
 


Patches currently in stable-queue which might be from jiho.chu@samsung.com are

queue-4.4/can-peak-fix-bad-memory-access-and-free-sequence.patch