From: Antoine Tenart <atenart@kernel.org>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com
Cc: steffen.klassert@secunet.com, netdev@vger.kernel.org
Subject: Re: [PATCH net 2/4] gro: fix ownership transfer
Date: Mon, 18 Mar 2024 10:09:40 +0100 [thread overview]
Message-ID: <171075298053.25781.9212858495086366536@kwain> (raw)
In-Reply-To: <65f5b9d952450_6ef3e294f1@willemb.c.googlers.com.notmuch>
Quoting Willem de Bruijn (2024-03-16 16:25:13)
> Antoine Tenart wrote:
> > Issue was found while using rx-gro-list. If fragmented packets are GROed
>
> Only if you need to respin: "If packets are GROed with fraglist"
>
> A bit pedantic, but this is subtle stuff. These are not IP fragmented
> packets. Or worse, UDP fragmentation offload.
Right, that was only describing which kind of packets were GROed in my
test. Looks like that's confusing, I'll remove it.
> > in skb_gro_receive_list, they might be segmented later on and continue
> > their journey in the stack. In skb_segment_list those skbs can be reused
> > as-is. This is an issue as their destructor was removed in
> > skb_gro_receive_list but not the reference to their socket, and then
> > they can't be orphaned. Fix this by also removing the reference to the
> > socket.
> >
> > For example this could be observed,
> >
> > kernel BUG at include/linux/skbuff.h:3131! (skb_orphan)
> > RIP: 0010:ip6_rcv_core+0x11bc/0x19a0
> > Call Trace:
> > ipv6_list_rcv+0x250/0x3f0
> > __netif_receive_skb_list_core+0x49d/0x8f0
> > netif_receive_skb_list_internal+0x634/0xd40
> > napi_complete_done+0x1d2/0x7d0
> > gro_cell_poll+0x118/0x1f0
> >
> > A similar construction is found in skb_gro_receive, apply the same
> > change there.
> >
> > Fixes: 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb carring sock reference")
> > Signed-off-by: Antoine Tenart <atenart@kernel.org>
>
> Looks fine to me on the understanding that the only GSO packets that
> arrive with skb->sk are are result of the referenced commit, and thus
> had sock_wfree as destructor.
The root cause of the issue is a disparity between skb->destructor and
skb->sk; either skb with skb->{destructor,sk} could arrive there and
that was not an issue, or they could not. In both cases the above commit
is introducing that behavior.
Thanks!
Antoine
next prev parent reply other threads:[~2024-03-18 9:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-15 15:17 [PATCH net 0/4] gro: various fixes related to UDP tunnels Antoine Tenart
2024-03-15 15:17 ` [PATCH net 1/4] udp: do not accept non-tunnel GSO skbs landing in a tunnel Antoine Tenart
2024-03-15 21:21 ` kernel test robot
2024-03-18 10:03 ` Antoine Tenart
2024-03-15 21:43 ` kernel test robot
2024-03-16 14:05 ` Willem de Bruijn
2024-03-15 15:17 ` [PATCH net 2/4] gro: fix ownership transfer Antoine Tenart
2024-03-16 15:25 ` Willem de Bruijn
2024-03-18 9:09 ` Antoine Tenart [this message]
2024-03-15 15:17 ` [PATCH net 3/4] udp: do not transition UDP fraglist to unnecessary checksum Antoine Tenart
2024-03-15 15:17 ` [PATCH net 4/4] udp: prevent local UDP tunnel packets from being GROed Antoine Tenart
2024-03-16 15:43 ` Willem de Bruijn
2024-03-18 8:43 ` Antoine Tenart
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