On 03/08/2018 03:43 PM, Greg KH wrote:
On Thu, Mar 08, 2018 at 03:29:48PM -0800, sathyanarayanan kuppuswamy wrote:
On 03/08/2018 12:54 AM, Oliver Neukum wrote:
Am Mittwoch, den 07.03.2018, 13:41 -0800 schrieb sathyanarayanan
kuppuswamy :
On 03/07/2018 12:58 PM, Greg KH wrote:
So I don't see why your check is needed, what other code path would ever
call this function in a way that the bounds check would be needed?
void usb_serial_generic_read_bulk_callback(struct urb *urb)
385 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
386 if (urb == port->read_urbs[i])
387 break;
388 }
In here, after this for loop is done (without any matching urb), i value
will be equal to ARRAY_SIZE(port->read_urbs). So there is a possibility
of usb_serial_generic_submit_read_urb() getting called with this invalid
index.
If this happens the function was called for a stray URB.
Your check comes to late. We have called set_bit with an invalid index
and other shit.
We definitely do not just want to return an error in that case.
In that case do you think we should use some WARN_ON() for invalid index in
usb_serial_generic_read_bulk_callback()?
No, again, how could that ever happen?
Don't add pointless error checking for things that are impossible to
ever hit :)
Thanks Greg.
thanks,
greg k-h
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Sathyanarayanan Kuppuswamy
Linux kernel developer
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