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Patch "can: peak: fix bad memory access and free sequence" has been added to the 4.8-stable tree

PATCH [email protected] 1 participant 1 message Dec 13, 2016

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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 4.8-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-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From b67d0dd7d0dc9e456825447bbeb935d8ef43ea7c Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?=EC=B6=94=EC=A7=80=ED=98=B8?= <[email protected]>
Date: Thu, 8 Dec 2016 12:01:13 +0000
Subject: can: peak: fix bad memory access and free sequence

From: 추지호 <[email protected]>

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.

---
 drivers/net/can/usb/peak_usb/pcan_usb_core.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
drivers/net/can/usb/peak_usb/pcan_usb_core.c +4 -2
@@ -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 [email protected] are

queue-4.8/can-peak-fix-bad-memory-access-and-free-sequence.patch