Re: [PATCH AUTOSEL 4.19 592/671] USB: usb-skeleton: fix use-after-free after driver unbind

[Sasha Levin]

On Fri, Jan 17, 2020 at 11:21:16AM +0100, Johan Hovold wrote:
> On Thu, Jan 16, 2020 at 12:03:50PM -0500, Sasha Levin wrote:
> > From: Johan Hovold <johan@xxxxxxxxxx>
> >
> > [ Upstream commit 6353001852776e7eeaab4da78922d4c6f2b076af ]
> >
> > The driver failed to stop its read URB on disconnect, something which
> > could lead to a use-after-free in the completion handler after driver
> > unbind in case the character device has been closed.
> >
> > Fixes: e7389cc9a7ff ("USB: skel_read really sucks royally")
> > Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20191009170944.30057-3-johan@xxxxxxxxxx
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> This one isn't needed in any stable tree. As we discussed before, the
> skeleton driver is only there for documentation purposes.

I'll drop this, but I'm curious: doesn't this mean that users will build
on buggy example code?

--
Thanks,
Sasha