From: Steffen Klassert <steffen.klassert@secunet.com>
To: Paolo Abeni <pabeni@redhat.com>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Network Development <netdev@vger.kernel.org>,
"Willem de Bruijn" <willemb@google.com>,
Miaohe Lin <linmiaohe@huawei.com>,
"Jakub Kicinski" <kuba@kernel.org>
Subject: Re: [PATCH net 1/4] net: fix double-free on fraglist GSO skbs
Date: Tue, 11 May 2021 11:39:53 +0200 [thread overview]
Message-ID: <20210511093953.GT40979@gauss3.secunet.de> (raw)
In-Reply-To: <3e41198f79b4d63812e3862ca688507bf3f7d65d.camel@redhat.com>
On Mon, May 10, 2021 at 05:37:58PM +0200, Paolo Abeni wrote:
>
> It's taking [much] more than expected, as it turned out that thare are
> still a number of case where the tx csum is uncorrect.
>
> If the traffic comes from a veth we don't have a valid th->csum value
> at GRO time, setting ip_summed to CHECKSUM_UNNECESSARY - as the current
> code does - looks wrong.
> @Steffen: I see in the original discussion about GRO_FRAGLIST
> introduction that you wanted the GRO packets to be CHECKSUM_UNNECESSARY
> to avoid csum modification in fwd path. I guess that choice was mostily
> due performance reasons, to avoid touching the aggregated pkts header
> at gso_segment_list time, but it looks like it's quite bug prone. If
> so, I'm unsure the performance gain is worty.
Yes, that was for performance reasons. We don't mangle the packets
with fraglist GRO, so the checksum should be still correct when
doing GSO.
> I propose to switch to
> CHECKSUM_PARTIAL. Would you be ok with that?
If there are cases where CHECKSUM_UNNECESSARY is problematic,
then yes, let's switch to CHECKSUM_PARTIAL.
Thanks for doing this Paolo!
next prev parent reply other threads:[~2021-05-11 9:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-05 15:35 [PATCH net 0/4] udp: more FRAGLIST fixes Paolo Abeni
2021-05-05 15:35 ` [PATCH net 1/4] net: fix double-free on fraglist GSO skbs Paolo Abeni
2021-05-05 16:13 ` Willem de Bruijn
2021-05-05 17:28 ` Paolo Abeni
2021-05-05 17:30 ` Willem de Bruijn
2021-05-06 11:06 ` Paolo Abeni
2021-05-06 14:32 ` Willem de Bruijn
2021-05-06 15:55 ` Paolo Abeni
2021-05-06 21:17 ` Jakub Kicinski
2021-05-07 8:46 ` Paolo Abeni
2021-05-10 15:37 ` Paolo Abeni
2021-05-11 9:39 ` Steffen Klassert [this message]
2021-05-05 15:35 ` [PATCH net 2/4] udp: fix out-of-bound at segmentation time Paolo Abeni
2021-05-05 15:35 ` [PATCH net 3/4] udp: fix outer header csum for SKB_GSO_FRAGLIST over UDP tunnel Paolo Abeni
2021-05-05 15:35 ` [PATCH net 4/4] selftests: more UDP GRO tests Paolo Abeni
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