Re: [PATCH] sh: bug: add unreachable() to silence warnings

From: Josh Triplett
Date: Thu Aug 07 2014 - 01:10:35 EST


On Thu, Aug 07, 2014 at 03:42:20AM +0200, Nick Krause wrote:
> SuperH BUG() have warnings like
>
> kernel/sched/core.c:2692:1: warning: control reaches end of non-void function
> [-Wreturn-type]
> net/core/ethtool.c:236:1: warning: control reaches end of non-void function
> [-Wreturn-type]
>
> Other BUG() implementations
> have added unreachable() at end becuase of which I guess
> it does not showthese errors. We can silence them using unreachable().
>
> Signed-off-by: Nick Krause <xerofoify@xxxxxxxxx>

This change seems reasonable to me. Unlike the generic version of
BUG(), this one doesn't call panic() or anything else flagged as
__noreturn, so it seems reasonable to add a call to unreachable() here
to tell the compiler that the assembly will trap and not return.

Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>

> arch/sh/include/asm/bug.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
> index dcf2780..1ae948f 100644
> --- a/arch/sh/include/asm/bug.h
> +++ b/arch/sh/include/asm/bug.h
> @@ -48,6 +48,7 @@ do { \
> "i" (__FILE__), \
> "i" (__LINE__), "i" (0), \
> "i" (sizeof(struct bug_entry))); \
> + unreachable(); \
> } while (0)
>
> #define __WARN_TAINT(taint) \
> --
> 2.0.1
>
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