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Subject: Re: [PATCH 2/3] drm/i915/selftests: Always initialize err in
 igt_dmabuf_import_same_driver_lmem()
To:     Nathan Chancellor <nathan@kernel.org>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc:     Jason Ekstrand <jason@jlekstrand.net>,
        Matthew Auld <matthew.auld@intel.com>,
        "Michael J. Ruhl" <michael.j.ruhl@intel.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
        llvm@lists.linux.dev, Dan Carpenter <dan.carpenter@oracle.com>
References: <20210824225427.2065517-1-nathan@kernel.org>
 <20210824225427.2065517-3-nathan@kernel.org>
From:   =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= 
        <thomas.hellstrom@linux.intel.com>
Message-ID: <354f7760-7b43-8e3f-414b-1556dabbcdb3@linux.intel.com>
Date:   Wed, 25 Aug 2021 11:57:25 +0200
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On 8/25/21 12:54 AM, Nathan Chancellor wrote:
> Clang warns:
>
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:127:13: warning:
> variable 'err' is used uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
>          } else if (PTR_ERR(import) != -EOPNOTSUPP) {
>                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:138:9: note:
> uninitialized use occurs here
>          return err;
>                 ^~~
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:127:9: note: remove
> the 'if' if its condition is always true
>          } else if (PTR_ERR(import) != -EOPNOTSUPP) {
>                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c:95:9: note:
> initialize the variable 'err' to silence this warning
>          int err;
>                 ^
>                  = 0
>
> The test is expected to pass if i915_gem_prime_import() returns
> -EOPNOTSUPP so initialize err to zero in this case.
>
> Fixes: cdb35d1ed6d2 ("drm/i915/gem: Migrate to system at dma-buf attach time (v7)")
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>