From b67d0dd7d0dc9e456825447bbeb935d8ef43ea7c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=EC=B6=94=EC=A7=80=ED=98=B8?= Date: Thu, 8 Dec 2016 12:01:13 +0000 Subject: [PATCH] can: peak: fix bad memory access and free sequence 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 Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/usb/peak_usb/pcan_usb_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c index f3141ca56bc3..0b0302af3bd2 100644 --- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c +++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c @@ -870,23 +870,25 @@ 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); }