[igt-dev] [PATCH i-g-t] lib/ioctl_wrappers: Assert that prime_handle_to_fd returns a valid fd

[Petri Latvala]

On Tue, Mar 12, 2019 at 11:34:37AM +0000, Chris Wilson wrote:
> Quoting Petri Latvala (2019-03-12 11:21:14)
> > If the ioctl is successful, the returned fd should be valid. Check
> > that it is, thus also helping static analysis in almost 70 call sites.
> > 
> > Signed-off-by: Petri Latvala <petri.latvala at intel.com>
> > ---
> >  lib/ioctl_wrappers.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/lib/ioctl_wrappers.c b/lib/ioctl_wrappers.c
> > index 39920f87..31969e77 100644
> > --- a/lib/ioctl_wrappers.c
> > +++ b/lib/ioctl_wrappers.c
> > @@ -1332,6 +1332,7 @@ int prime_handle_to_fd(int fd, uint32_t handle)
> >         args.fd = -1;
> >  
> >         do_ioctl(fd, DRM_IOCTL_PRIME_HANDLE_TO_FD, &args);
> > +       igt_assert_fd(args.fd);
> 
> Why? Why would we be using a static analysis tool that complains about
> feeding invalid data to the kernel, because that is exactly the goal of
> igt.

Because after teaching it what data should be invalid and what should
be valid, it has already revealed a couple of bugs?

Are you objecting to checking that the ioctl gives an fd that is >= 0?
Where's the line here, what parts of the uapi semantics must always be
left unchecked in a test suite for uapi?


-- 
Petri Latvala