linux-kernel - Re: [PATCH v1 02/27] powerpc/mm: don't BUG in add_huge_page

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Date:   Thu, 11 Apr 2019 11:11:13 +0530
From:   "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
To:     Christophe Leroy <christophe.leroy@....fr>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 02/27] powerpc/mm: don't BUG in add_huge_page_size()

Christophe Leroy <christophe.leroy@....fr> writes:

> No reason to BUG() in add_huge_page_size(). Just WARN and
> reject the add.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> ---
>  arch/powerpc/mm/hugetlbpage.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
> index 9e732bb2c84a..cf2978e235f3 100644
> --- a/arch/powerpc/mm/hugetlbpage.c
> +++ b/arch/powerpc/mm/hugetlbpage.c
> @@ -634,7 +634,8 @@ static int __init add_huge_page_size(unsigned long long size)
>  	}
>  #endif
>  
> -	BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
> +	if (WARN_ON(mmu_psize_defs[mmu_psize].shift != shift))
> +		return -EINVAL;

Same here. There are not catching runtime errors. We should never find
that true. This is to catch mistakes during development changes. Switch
to VM_BUG_ON?


>  
>  	/* Return if huge page size has already been setup */
>  	if (size_to_hstate(size))
> -- 
> 2.13.3