ip6_gre: Initialise ign->tunnels_wc[0] before register_netdev().

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ip6gre_init_net() links the fallback device ip6gre0 to
ign->tunnels_wc[0] after publishing it by register_netdev().

While ip6_gre module is being loaded, there is a small race window.

If ioctl(SIOCADDTUNNEL) is called before ip6gre0 is linked to
the hash table, a new device could be linked to ign->tunnels_wc[0].

Then, the fallback device overwrites ign->tunnels_wc[0], and the new
device will be no longer found by ip6gre_tunnel_lookup(), resulting
in no RX.

Let's link the fallback device before register_netdev().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260916230353.367014-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

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Kuniyuki Iwashima 2026-09-16 23:02:20 +00:00 • committed by Jakub Kicinski

parent 5249efe2f5

commit 3e6af2e485

1 changed files with 3 additions and 2 deletions

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net/ipv6/ip6_gre.c

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