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From: Kees Cook <keescook@chromium.org>
To: Miroslav Benes <mbenes@suse.cz>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: Re: sparse warnings in overflow.h
Date: Thu, 7 Jun 2018 11:35:31 -0700	[thread overview]
Message-ID: <CAGXu5j+XFR7BtYPU6G4CeLFREWevN+GC1FPX1hPAYA1LRBM9Bg@mail.gmail.com> (raw)
In-Reply-To: <alpine.LSU.2.21.1806071258310.7958@pobox.suse.cz>

On Thu, Jun 7, 2018 at 4:01 AM, Miroslav Benes <mbenes@suse.cz> wrote:
>
> Hi Kees,
>
> sparse (make C=1) gives me this warnings today...
>
> ./include/linux/overflow.h:254:13: error: undefined identifier '__builtin_mul_overflow'
> ./include/linux/overflow.h:254:13: error: incorrect type in conditional
> ./include/linux/overflow.h:254:13:    got void
> ./include/linux/overflow.h:256:13: error: undefined identifier '__builtin_add_overflow'
> ./include/linux/overflow.h:256:13: error: incorrect type in conditional
> ./include/linux/overflow.h:256:13:    got void
>
> This hunk obviously fixes it, but I'm really not sure if it is a proper
> fix.
>
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index f1a7492a5cc8..15e55b89e952 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -344,6 +344,6 @@
>   */
>  #define uninitialized_var(x) x = x
>
> -#if GCC_VERSION >= 50100
> +#if GCC_VERSION >= 50100 && !defined(__CHECKER__)
>  #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
>  #endif
>
> Any idea?

Hi! Yeah, that's probably the correct approach. If the checker doesn't
have it, the builtins need to be disabled. :)

Can you send this with a Signed-off-by line, etc, and I'll take it for
sending to Linus?

Thanks!

-Kees

-- 
Kees Cook
Pixel Security

  reply	other threads:[~2018-06-07 18:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07 11:01 Miroslav Benes
2018-06-07 18:35 ` Kees Cook [this message]
2018-06-07 19:25   ` Rasmus Villemoes
2018-06-07 23:45     ` Luc Van Oostenryck
2018-06-08  6:34   ` [PATCH] compiler-gcc.h: don't set COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW for sparse Miroslav Benes

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