syzbot report in rsi_91x_usb.c

From: Julia Lawall
Date: Tue Sep 10 2019 - 15:11:21 EST


Hello,

I spent some time looking at:

https://syzkaller.appspot.com/bug?id=c1b6aa968706d9380dcdb98a9f2c338071cc938c

which does not yet report that it has been fixed.

The problem seems to be in rsi_probe in
drivers/net/wireless/rsi/rsi_91x_usb.c. This ends with the following
code:

status = rsi_rx_urb_submit(adapter, WLAN_EP);
if (status)
goto err1;

if (adapter->priv->coex_mode > 1) {
status = rsi_rx_urb_submit(adapter, BT_EP);
if (status)
goto err1;
}

return 0;
err1:
rsi_deinit_usb_interface(adapter);
err:
rsi_91x_deinit(adapter);


The problem seems to be that the first call to rsi_rx_urb_submit succeeds,
submitting an urb, and then theh second one fails. Both share adapter,
which is used in rsi_rx_done_handler, invoked later as the callback
provided with usb_submit_urb. But adapter, and in particular its rsi_dev
field, are freed by the rsi_91x_deinit call due to the failure of the
second call to rsi_rx_urb_submit.

How should this be fixed?

thanks,
julia