geneve: Protect geneve_net and geneve_sock with per-netns mutex.

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struct geneve_dev.net is the netns where the backend geneve
socket resides.

struct geneve_dev is linked to the geneve_net.geneve_list of
the socket's netns.

During netns dismantle or module unload, geneve_exit_rtnl_net()
iterates the list and queues devices for destruction regardless
of devices' netns.

Moreover, a socket can be shared by multiple geneve devices in
different netns, and geneve_open() and geneve_stop() modify
geneve_sock.vni_list and geneve_net.sock_list.

Thus, once RTNL is removed, the three lists can be modified
concurrently from different netns due to device removal and
link-up/down.

Let's protect them with per-netns mutex.

geneve_newlink() is still protected by rtnl_net_lock()s, so
acquiring gn->lock twice in geneve_find_dev() and
geneve_configure() is not a problem.

Note that udp_tunnel_notify_add_rx_port() is moved outside of
the mutex, otherwise gn->lock -> utn->lock ordering would trigger
AB-BA deadlock in geneve_offload_rx_ports(), which acquires
gn->lock under utn->lock.  Even without gn->lock, geneve_sock_add()
and geneve_offload_rx_ports() are still serialised with (per-netns)
RTNL, so there is no race.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260731164612.2148830-3-kuniyu@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

...

This commit is contained in:

Kuniyuki Iwashima 2026-07-31 16:45:54 +00:00 • committed by Paolo Abeni

parent cf31c7f186

commit 7df47efd6d

1 changed files with 68 additions and 14 deletions

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drivers/net/geneve.c

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