Re: Several races in "usbnet" module (kernel 4.1.x)

23.07.2015 12:43, Oliver Neukum пишет:

On Mon, 2015-07-20 at 21:13 +0300, Eugene Shatokhin wrote:

quoted

[Race #5]

Race on dev->rx_urb_size. I reproduced it a similar way as the races
#2
and #3 (changing MTU while downloading files).

dev->rx_urb_size is written to here:
#0  usbnet_change_mtu (usbnet.c:392)
         dev->rx_urb_size = dev->hard_mtu;

Here is the conflicting read from dev->rx_urb_size:
* rx_submit (usbnet.c:467)
         size_t                  size = dev->rx_urb_size;

Yes, but what is the actual bad race? I mean, if you change
the MTU in operation, there will be a race. That is just
unavoidable.
Do we generate errors?

No, I have observed no problems due to this race so far.

Regards,
Eugene