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Date: Wed, 2 Feb 2022 12:01:35 +0100
From: Antoine Tenart <atenart@...nel.org>
To: davem@...emloft.net, kuba@...nel.org
Cc: Antoine Tenart <atenart@...nel.org>, netdev@...r.kernel.org,
vladbu@...dia.com, pabeni@...hat.com, pshelar@....org
Subject: [PATCH net 0/2] net: fix issues when uncloning an skb dst+metadata
Hi,
This fixes two issues when uncloning an skb dst+metadata in
tun_dst_unclone; this was initially reported by Vlad Buslov[1]. Because
of the memory leak fixed by patch 2, the issue in patch 1 never happened
in practice.
tun_dst_unclone is called from two different places, one in geneve/vxlan
to handle PMTU and one in net/openvswitch/actions.c where it is used to
retrieve tunnel information. While both Vlad and I tested the former, we
could not for the latter. I did spend quite some time trying to, but
that code path is not easy to trigger. Code inspection shows this should
be fine, the tunnel information (dst+metadata) is uncloned and the skb
it is referenced from is only consumed after all accesses to the tunnel
information are done:
do_execute_actions
output_userspace
dev_fill_metadata_dst <- dst+metadata is uncloned
ovs_dp_upcall
queue_userspace_packet
ovs_nla_put_tunnel_info <- metadata (tunnel info) is accessed
consume_skb <- dst+metadata is freed
Thanks!
Antoine
[1] https://lore.kernel.org/all/ygnhh79yluw2.fsf@nvidia.com/T/#m2f814614a4f5424cea66bbff7297f692b59b69a0
Antoine Tenart (2):
net: do not keep the dst cache when uncloning an skb dst and its
metadata
net: fix a memleak when uncloning an skb dst and its metadata
include/net/dst_metadata.h | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--
2.34.1
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