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Subject: Re: [PATCH ipsec-next v1 8/8] iptfs: impl: add new iptfs xfrm mode
 impl
From: Christian Hopps <chopps@chopps.org>
In-Reply-To: <20240226205746.GK13129@kernel.org>
Date: Thu, 29 Feb 2024 04:12:17 -0500
Cc: Christian Hopps <chopps@chopps.org>,
 devel@linux-ipsec.org,
 Steffen Klassert <steffen.klassert@secunet.com>,
 netdev@vger.kernel.org
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References: <20240219085735.1220113-1-chopps@chopps.org>
 <20240219085735.1220113-9-chopps@chopps.org>
 <20240219201349.GO40273@kernel.org> <m24je013cj.fsf@ja.int.chopps.org>
 <20240226205746.GK13129@kernel.org>
To: Simon Horman <horms@kernel.org>
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> On Feb 26, 2024, at 15:57, Simon Horman <horms@kernel.org> wrote:
>=20
> On Thu, Feb 22, 2024 at 03:23:36PM -0500, Christian Hopps wrote:
>>=20
>> Simon Horman <horms@kernel.org> writes:
>>=20
>>> On Mon, Feb 19, 2024 at 03:57:35AM -0500, Christian Hopps wrote:
>>>> From: Christian Hopps <chopps@labn.net>
...
>>>> +/**
>>>> + * skb_head_to_frag() - initialize a skb_frag_t based on skb head =
data
>>>> + * @skb: skb with the head data
>>>> + * @frag: frag to initialize
>>>> + */
>>>> +static void skb_head_to_frag(const struct sk_buff *skb, skb_frag_t =
*frag)
>>>> +{
>>>> + struct page *page =3D virt_to_head_page(skb->data);
>>>> + unsigned char *addr =3D (unsigned char *)page_address(page);
>>>> +
>>>> + BUG_ON(!skb->head_frag);
>>>=20
>>> Is it strictly necessary to crash the Kernel here?
>>> Likewise, many other places in this patch.
>>=20
>> In all use cases it represents a programming error (bug) if the =
condition is met.
>>=20
>> What is the correct use of BUG_ON?
>=20
> Hi Christian,
>=20
> I would say that BUG_ON should used in situations where
> there is an unrecoverable error to the extent where
> the entire system cannot continue to function.

Well in these cases it means that IPsec/IPTFS is in an unrecoverable =
state and broken. It's hard to predict how much that means "entire" to =
the user that expects their IPsec tunnels to be working, it may be the =
entire purpose of the box it's running on, so normally I don't think =
it's wise to try.

If you still object I will remove them.

Thanks,
Chris.

>=20
> ...