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

Jani Nikula
2018-11-26T12:09:47Z

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.

> + 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