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From: Jakub Kicinski <kuba@kernel.org>
To: Florian Westphal <fw@strlen.de>
Cc: Ido Schimmel <idosch@idosch.org>,
	Aleksandr Nogikh <aleksandrnogikh@gmail.com>,
	davem@davemloft.net, johannes@sipsolutions.net,
	edumazet@google.com, andreyknvl@google.com, dvyukov@google.com,
	elver@google.com, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
	willemdebruijn.kernel@gmail.com,
	Aleksandr Nogikh <nogikh@google.com>,
	Willem de Bruijn <willemb@google.com>
Subject: Re: [PATCH v5 2/3] net: add kcov handle to skb extensions
Date: Sat, 21 Nov 2020 10:06:36 -0800	[thread overview]
Message-ID: <20201121100636.26aaaf8a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20201121165227.GT15137@breakpoint.cc>

On Sat, 21 Nov 2020 17:52:27 +0100 Florian Westphal wrote:
> Ido Schimmel <idosch@idosch.org> wrote:
> > Other suggestions?  
> 
> Aleksandr, why was this made into an skb extension in the first place?
> 
> AFAIU this feature is usually always disabled at build time.
> For debug builds (test farm /debug kernel etc) its always needed.
> 
> If thats the case this u64 should be an sk_buff member, not an
> extension.

Yeah, in hindsight I should have looked at how it's used. Not a great
fit for extensions. We can go back, but...

In general I'm not very happy at how this is going. First of all just
setting the handle in a couple of allocs seems to not be enough, skbs
get cloned, reused etc. There were also build problems caused by this
patch and Aleksandr & co where nowhere to be found. Now we find out
this causes leaks, how was that not caught by the syzbot it's supposed
to serve?!

So I'm leaning towards reverting the whole thing. You can attach
kretprobes and record the information you need in BPF maps.

  parent reply	other threads:[~2020-11-21 18:07 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-29 17:36 [PATCH v5 0/3] net, mac80211, kernel: enable KCOV remote coverage collection for 802.11 frame handling Aleksandr Nogikh
2020-10-29 17:36 ` [PATCH v5 1/3] kernel: make kcov_common_handle consider the current context Aleksandr Nogikh
2020-10-29 17:36 ` [PATCH v5 2/3] net: add kcov handle to skb extensions Aleksandr Nogikh
2020-11-21 16:09   ` Ido Schimmel
2020-11-21 16:52     ` Florian Westphal
2020-11-21 17:39       ` Johannes Berg
2020-11-21 18:06       ` Jakub Kicinski [this message]
2020-11-21 18:12         ` Johannes Berg
2020-11-21 18:35           ` Jakub Kicinski
2020-11-21 19:30             ` Johannes Berg
2020-11-21 20:55               ` Jakub Kicinski
2020-11-21 20:58                 ` Johannes Berg
2020-11-21 21:02                   ` Jakub Kicinski
2020-11-25 16:30                     ` Marco Elver
2020-12-01  1:52     ` Jakub Kicinski
2020-12-01  7:35       ` Ido Schimmel
2020-12-01 16:43         ` Jakub Kicinski
2020-10-29 17:36 ` [PATCH v5 3/3] mac80211: add KCOV remote annotations to incoming frame processing Aleksandr Nogikh
2020-10-29 17:44   ` Johannes Berg
2020-10-29 18:00     ` Marco Elver
2020-10-29 19:08       ` Andrey Konovalov
2020-11-03  3:00 ` [PATCH v5 0/3] net, mac80211, kernel: enable KCOV remote coverage collection for 802.11 frame handling Jakub Kicinski

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