From: Dongliang Mu <mudongliangabcd@xxxxxxxxx> flush_work will throw one WARN if worker->func is NULL. So we should always initialize one worker before calling flush_work. When hdpvr_probe does not initialize its worker, the hdpvr_disconnect will encounter one WARN. The stack trace is in the following: hdpvr_disconnect+0xb8/0xf2 drivers/media/usb/hdpvr/hdpvr-core.c:425 usb_unbind_interface+0xbf/0x3a0 drivers/usb/core/driver.c:458 __device_release_driver drivers/base/dd.c:1206 [inline] device_release_driver_internal+0x22a/0x230 drivers/base/dd.c:1237 bus_remove_device+0x108/0x160 drivers/base/bus.c:529 device_del+0x1fe/0x510 drivers/base/core.c:3592 usb_disable_device+0xd1/0x1d0 drivers/usb/core/message.c:1419 usb_disconnect+0x109/0x330 drivers/usb/core/hub.c:2228 Fix this by adding a sanity check of the worker before flush_work. Reported-by: syzkaller <syzkaller@xxxxxxxxxxxxxxxx> Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx> --- drivers/media/usb/hdpvr/hdpvr-core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/hdpvr/hdpvr-core.c b/drivers/media/usb/hdpvr/hdpvr-core.c index 52e05a69c46e..d102b459d45d 100644 --- a/drivers/media/usb/hdpvr/hdpvr-core.c +++ b/drivers/media/usb/hdpvr/hdpvr-core.c @@ -422,7 +422,8 @@ static void hdpvr_disconnect(struct usb_interface *interface) mutex_unlock(&dev->io_mutex); v4l2_device_disconnect(&dev->v4l2_dev); msleep(100); - flush_work(&dev->worker); + if (dev->worker.func) + flush_work(&dev->worker); mutex_lock(&dev->io_mutex); hdpvr_cancel_queue(dev); mutex_unlock(&dev->io_mutex); -- 2.25.1
