Re: [syzbot] KASAN: use-after-free Read in dev_uevent

gregkh
2022-02-26T09:07:12Z

On Fri, Feb 25, 2022 at 10:51:48AM -0500, stern@rowland.harvard.edu wrote:
> On Fri, Feb 25, 2022 at 09:53:35AM +0100, gregkh@linuxfoundation.org wrote:
> > On Thu, Feb 24, 2022 at 09:06:13PM -0500, stern@rowland.harvard.edu wrote:
> > > On Thu, Feb 24, 2022 at 11:37:39PM +0100, gregkh@linuxfoundation.org wrote:
> > > > On Thu, Feb 24, 2022 at 04:23:26PM -0500, stern@rowland.harvard.edu wrote:
> > > > > Can you tell us how this should be fixed?
> > > >
> > > > It should be fixed by properly using the driver core to bind/unbind the
> > > > driver to devices like I mentioned previously :)
> > >
> > > This would involve creating a "gadget" bus_type (or should it be a
> > > device_type under the platform bus?) and registering the gadgets
> > > on it, right?.
> >
> > Yes. Or you can use the aux bus for this, which might be easier.
> >
> > > Similarly, the gadget drivers would be registered on
> > > this bus. I suppose we can control which drivers get bound to which
> > > gadgets with careful matching code.
> >
> > The aux bus might make this easier:
> > Documentation/driver-api/auxiliary_bus.rst
>
> Won't this end up changing the user-visible filenames and directories in
> sysfs for gadgets and gadget drivers?
>
> For instance, currently gadgets get registered under their UDC driver
> name, like "net2280" or "at91". If we put them on the aux bus then they
> will have to get registered under a name looking something like
> "udc.gadget.0", i.e., module name, generic device name, and ID number.

Ah, yeah, that isn't good.

> We will be forced to use a generic device name because the aux bus does
> matching based on it, and we want every gadget driver to be able to
> match every UDC. We don't want some gadget drivers restricted to
> net2280 gadgets, others restricted to fotg210 gadgets, and so on.

So yes, I guess it does need to be a "real" bus, sorry.

thanks,

greg k-h