netdev - Re: [PATCH net-next] net: skbuff: Skip early return in skb

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Message-ID: <c61c4921-0ddc-42cf-881d-4302ff599053@redhat.com>
Date: Tue, 30 Jul 2024 13:15:57 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Florian Westphal <fw@...len.de>
Cc: Breno Leitao <leitao@...ian.org>, "David S. Miller"
 <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, leit@...a.com, Chris Mason <clm@...com>,
 "open list:NETWORKING DRIVERS" <netdev@...r.kernel.org>,
 open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net-next] net: skbuff: Skip early return in skb_unref when
 debugging

On 7/30/24 12:50, Florian Westphal wrote:
> Paolo Abeni <pabeni@...hat.com> wrote:
>>>    	else if (likely(!refcount_dec_and_test(&skb->users)))
>>>    		return false;
>>
>> I think one assumption behind CONFIG_DEBUG_NET is that enabling such config
>> should not have any measurable impact on performances.
> 
> If thats the case why does it exist at all?
> 
> I was under impression that entire reason for CONFIG_DEBUG_NET was
> to enable more checks for fuzzers and the like, i.e. NOT for production
> kernels.

I feel like I already had this discussion and I forgot the outcome, if 
so I'm sorry. To me the "but is safe to select." part in the knob 
description means this could be enabled in production, and AFAICS the 
CONFIG_DEBUG_NET-enabled code so far respects that assumption.

Thanks,

Paolo