On close this timer might be scheduled. mptcp uses sk_reset_timer for
this, so the a reference on the mptcp socket is taken.
This causes a refcount leak which can for example be reproduced
with 'mp_join_server_v4.pkt' from the mptcp-packetdrill repo.
The leak has nothing to do with join requests, v1_mp_capable_bind_no_cs.pkt
works too when replacing the last ack mpcapable to v1 instead of v0.
unreferenced object 0xffff888109bba040 (size 2744):
comm "packetdrill", [..]
backtrace:
[..] sk_prot_alloc.isra.0+0x2b/0xc0
[..] sk_clone_lock+0x2f/0x740
[..] mptcp_sk_clone+0x33/0x1a0
[..] subflow_syn_recv_sock+0x2b1/0x690 [..]
Fixes: e16163b6e2 ("mptcp: refactor shutdown and close")
Cc: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20201124162446.11448-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
b6d69fc8e8