Re: [PATCH v2] net/core: Fix BUG to BUG_ON conditionals.

[Alexei Starovoitov]

On Mon, Oct 09, 2017 at 11:37:59AM -0400, Tim Hansen wrote:
> Fix BUG() calls to use BUG_ON(conditional) macros.
> 
> This was found using make coccicheck M=net/core on linux next
> tag next-2017092
> 
> Signed-off-by: Tim Hansen <devtimhansen@xxxxxxxxx>
> ---
>  net/core/skbuff.c | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index d98c2e3ce2bf..34ce4c1a0f3c 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -1350,8 +1350,7 @@ struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
>  	/* Set the tail pointer and length */
>  	skb_put(n, skb->len);
>  
> -	if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
> -		BUG();
> +	BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));

I'm concerned with this change.
1. Calling non-trivial bit of code inside the macro is a poor coding style (imo)
2. BUG_ON != BUG. Some archs like mips and ppc have HAVE_ARCH_BUG_ON and implementation
of BUG and BUG_ON look quite different.

I'd prefer to keep the code as-is.