| Message ID | 20200621104326.30604-1-tuomas.tynkkynen@iki.fi |
|---|---|
| State | New |
| Headers | show |
| Series | usbnet: smsc95xx: Fix use-after-free after removal | expand |
diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c index 355be77f4241..3cf4dc3433f9 100644 --- a/drivers/net/usb/smsc95xx.c +++ b/drivers/net/usb/smsc95xx.c @@ -1324,7 +1324,7 @@ static void smsc95xx_unbind(struct usbnet *dev, struct usb_interface *intf) struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]); if (pdata) { - cancel_delayed_work(&pdata->carrier_check); + cancel_delayed_work_sync(&pdata->carrier_check); netif_dbg(dev, ifdown, dev->net, "free pdata\n"); kfree(pdata); pdata = NULL;
Syzbot reports an use-after-free in workqueue context: BUG: KASAN: use-after-free in mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737 mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737 __smsc95xx_mdio_read drivers/net/usb/smsc95xx.c:217 [inline] smsc95xx_mdio_read+0x583/0x870 drivers/net/usb/smsc95xx.c:278 check_carrier+0xd1/0x2e0 drivers/net/usb/smsc95xx.c:644 process_one_work+0x777/0xf90 kernel/workqueue.c:2274 worker_thread+0xa8f/0x1430 kernel/workqueue.c:2420 kthread+0x2df/0x300 kernel/kthread.c:255 It looks like that smsc95xx_unbind() is freeing the structures that are still in use by the concurrently running workqueue callback. Thus switch to using cancel_delayed_work_sync() to ensure the work callback really is no longer active. Reported-by: syzbot+29dc7d4ae19b703ff947@syzkaller.appspotmail.com Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi> --- Compile tested only. --- drivers/net/usb/smsc95xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)