[PATCH] kbuild: Enable -Wuninitialized

[PATCH] kbuild: Enable -Wuninitialized

[Nathan Chancellor]

This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:

https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

We very much want to catch these so turn this warning on so that CI is
aware of it.

Link: https://github.com/ClangBuiltLinux/linux/issues/381
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 scripts/Makefile.extrawarn | 1 -
 1 file changed, 1 deletion(-)

diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 98081ab300e5..699683a7c116 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -71,6 +71,5 @@ KBUILD_CFLAGS += -Wno-unused-value
 KBUILD_CFLAGS += -Wno-format
 KBUILD_CFLAGS += -Wno-sign-compare
 KBUILD_CFLAGS += -Wno-format-zero-length
-KBUILD_CFLAGS += -Wno-uninitialized
 endif
 endif
-- 
2.22.0

Re: [PATCH] kbuild: Enable -Wuninitialized

[Nick Desaulniers]

On Fri, Jun 14, 2019 at 9:53 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> This helps fine very dodgy behavior through both -Wuninitialized
> (warning that a variable is always uninitialized) and
> -Wsometimes-uninitialized (warning that a variable is sometimes
> uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
> catch things that GCC doesn't such as:
>
> https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

or this one, which was my favorite, and quite insidious from an
underhanded C contest perspective.
https://lore.kernel.org/lkml/20190226053855.7020-1-natechancellor@gmail.com/

Thank you very much for all the hard work you did tracking done and
fixing all of the cases we could find.  I very much look forward to
this patch as the capstone to all that work.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

>
> We very much want to catch these so turn this warning on so that CI is
> aware of it.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/381
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  scripts/Makefile.extrawarn | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
> index 98081ab300e5..699683a7c116 100644
> --- a/scripts/Makefile.extrawarn
> +++ b/scripts/Makefile.extrawarn
> @@ -71,6 +71,5 @@ KBUILD_CFLAGS += -Wno-unused-value
>  KBUILD_CFLAGS += -Wno-format
>  KBUILD_CFLAGS += -Wno-sign-compare
>  KBUILD_CFLAGS += -Wno-format-zero-length
> -KBUILD_CFLAGS += -Wno-uninitialized
>  endif
>  endif
> --
> 2.22.0
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH] kbuild: Enable -Wuninitialized

[Masahiro Yamada]

On Sat, Jun 15, 2019 at 1:53 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> This helps fine very dodgy behavior through both -Wuninitialized
> (warning that a variable is always uninitialized) and
> -Wsometimes-uninitialized (warning that a variable is sometimes
> uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
> catch things that GCC doesn't such as:
>
> https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/
>
> We very much want to catch these so turn this warning on so that CI is
> aware of it.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/381
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---

Applied to linux-kbuild.
Thanks!


-- 
Best Regards
Masahiro Yamada