From 7538fa33bb2f66b8b809ff39d58308be48e197a0 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 13 Oct 2026 16:29:20 +0200 Subject: [PATCH] mptcp: fix subflow bitfield misuse The subflow status bitfield is protected by the subflow socket lock, with one notable exception: the `close_event_done` bit is actually under the msk socket lock protection. As reported by Clashiko [1], flipping the latter bit may corrupt other entries in the same bitfield. Move the `close_event_done` outside the bitfield, in a 32bit hole. Link: https://lore.kernel.org/178959153492.22033.1944011998010756543@kernel.org Fixes: d82809b6c5f2 ("mptcp: avoid duplicated SUB_CLOSED events") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20261013-net-mptcp-misc-fixes-7-3-rc8-v1-2-932c9b182fc7@kernel.org Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 0384d6a023f9..c006110b1c56 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -583,14 +583,16 @@ struct mptcp_subflow_context { closing : 1, /* must not pass rx data to msk anymore */ valid_csum_seen : 1, /* at least one csum validated */ is_mptfo : 1, /* subflow is doing TFO */ - close_event_done : 1, /* has done the post-closed part */ mpc_drop : 1, /* the MPC option has been dropped in a rtx */ resetting : 1, /* subflow is resetting */ - __unused : 8; + __unused : 9; bool data_avail; bool scheduled; bool pm_listener; /* a listener managed by the kernel PM? */ bool fully_established; /* path validated */ + bool close_event_done; /* has done the post-closed part, + * protected by msk socket lock + */ u32 lent_mem_frag; u32 remote_nonce; u64 thmac;