[drm-xe:drm-xe-next 989/1016] drivers/gpu/drm/xe/xe_wait_user_fence.c:46:2: warning: variable 'passed' is used uninitialized whenever switch default is taken

[Lucas De Marchi]

On Mon, Dec 18, 2023 at 11:57:22AM -0700, Nathan Chancellor wrote:
>On Sun, Dec 17, 2023 at 03:28:47AM +0800, kernel test robot wrote:
>> tree:   https://gitlab.freedesktop.org/drm/xe/kernel.git drm-xe-next
>> head:   c54005fdd0347a17088e7ff78070a55bf9103bc4
>> commit: ad7d86415578e1a5deedb0ceed5c281f7367d66d [989/1016] drm/xe: Enable W=1 warnings by default
>> config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20231217/202312170357.KPSinwPs-lkp@intel.com/config)
>> compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231217/202312170357.KPSinwPs-lkp@intel.com/reproduce)
>>
>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>> the same patch/commit), kindly add following tags
>> | Reported-by: kernel test robot <lkp at intel.com>
>> | Closes: https://lore.kernel.org/oe-kbuild-all/202312170357.KPSinwPs-lkp@intel.com/
>>
>> All warnings (new ones prefixed by >>):
>>
>>    warning: unknown warning option '-Wrestrict' [-Wunknown-warning-option]
>>    warning: unknown warning option '-Wpacked-not-aligned'; did you mean '-Wpacked-non-pod'? [-Wunknown-warning-option]
>>    warning: unknown warning option '-Wformat-overflow'; did you mean '-Wshift-overflow'? [-Wunknown-warning-option]
>>    warning: unknown warning option '-Wformat-truncation' [-Wunknown-warning-option]
>>    warning: unknown warning option '-Wstringop-overflow'; did you mean '-Wshift-overflow'? [-Wunknown-warning-option]
>>    warning: unknown warning option '-Wstringop-truncation'; did you mean '-Wstring-concatenation'? [-Wunknown-warning-option]
>
>I am not sure why these warnings are even showing up in the first place,
>they are wrapped with cc-option, which should be catching that they are
>not supported... Is 0day doing something funky with KCFLAGS?
>Regardless...
>
>> >> drivers/gpu/drm/xe/xe_wait_user_fence.c:46:2: warning: variable 'passed' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
>>            default:
>>            ^~~~~~~
>>    drivers/gpu/drm/xe/xe_wait_user_fence.c:50:9: note: uninitialized use occurs here
>>            return passed ? 0 : 1;
>>                   ^~~~~~
>>    drivers/gpu/drm/xe/xe_wait_user_fence.c:21:13: note: initialize the variable 'passed' to silence this warning
>>            bool passed;
>>                       ^
>>                        = 0
>>    7 warnings generated.
>
>I was surprised that this was not caught sooner as
>-Wsometimes-uninitialized is a part of -Wall but it looks like
>drivers/gpu/drm/xe/Makefile was forked from the i915 Makefile before
>commit 43192617f781 ("drm/i915: Enable -Wsometimes-uninitialized") was
>added. It is good to see that the warnings are aligned now so that
>trivial uninitialized warnings can be caught by clang because they are
>disabled for GCC since commit 78a5255ffb6a ("Stop the ad-hoc games with
>-Wno-maybe-initialized") in 5.7. Will this be fixed as a separate patch?

https://lore.kernel.org/all/20231218163301.3453285-1-lucas.demarchi@intel.com/

Lucas De Marchi