Re: [igt-dev] [PATCH i-g-t] tests: close(fd) without igt_fixture considered harmful

Daniel Vetter
2018-11-26T14:26:10Z

On Mon, Nov 26, 2018 at 02:10:08PM +0200, Jani Nikula wrote:
> On Mon, 26 Nov 2018, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> > Some tests assume that close on an unopened fd is fine, except it's
> > not just unopened but actually stack garbage. There's a good chance we
> > end up running close(0), which wreaks the testcase enumeration. Fix
> > this.
> >
> > Not sure there's a better way to catch this than git grep plus lots of
> > manual auditing ... The unit tests only catch it by accident (x86
> > works fine, I hit it in one testcase only cross-building to aarch64).
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > ---
> > tests/i915/gem_pread_after_blit.c | 3 ++-
> > tests/i915/gem_tiled_fence_blits.c | 3 ++-
> > tests/i915/gem_tiled_swapping.c | 3 ++-
> > 3 files changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/tests/i915/gem_pread_after_blit.c b/tests/i915/gem_pread_after_blit.c
> > index 6ef3ca200776..cee9212749d6 100644
> > --- a/tests/i915/gem_pread_after_blit.c
> > +++ b/tests/i915/gem_pread_after_blit.c
> > @@ -248,5 +248,6 @@ igt_main
> > drm_intel_bufmgr_destroy(bufmgr);
> > }
> >
> > - close(fd);
>
> This one isn't stack garbage, it's guaranteed to be 0 for
> !igt_fixture. The other two are garbage on stack.
>
> The change is
>
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
>
> but please update the commit message.

Indeed! Noted in the commit message and pushed, thanks for your review.
-Daniel

>
> > + igt_fixture
> > + close(fd);
> > }
> > diff --git a/tests/i915/gem_tiled_fence_blits.c b/tests/i915/gem_tiled_fence_blits.c
> > index c02e35a5fe4c..2453bcc0b271 100644
> > --- a/tests/i915/gem_tiled_fence_blits.c
> > +++ b/tests/i915/gem_tiled_fence_blits.c
> > @@ -230,5 +230,6 @@ igt_main
> > run_test(fd, count);
> > }
> >
> > - close(fd);
> > + igt_fixture
> > + close(fd);
> > }
> > diff --git a/tests/i915/gem_tiled_swapping.c b/tests/i915/gem_tiled_swapping.c
> > index dce668063014..ddf2a748fc84 100644
> > --- a/tests/i915/gem_tiled_swapping.c
> > +++ b/tests/i915/gem_tiled_swapping.c
> > @@ -235,5 +235,6 @@ igt_main
> > thread_fini(&threads[n]);
> > }
> >
> > - close(fd);
> > + igt_fixture
> > + close(fd);
> > }
>
> --
> Jani Nikula, Intel Open Source Graphics Center

--
Daniel Vetter
Software Engineer, Intel Corporation