From: Tuomas Tynkkynen <tuomas.tynkkynen@xxxxxx> Date: Sun, 21 Jun 2020 13:43:26 +0300 > 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 is no longer active.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@xxxxxxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@xxxxxx> Applied, thanks.
