From nobody Fri Sep 25 10:03:20 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EE32932B13E; Sun, 20 Sep 2026 07:39:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789889981; cv=none; b=tLoKDclx2V2vTKk5e9KIY41y1hYOW4TFzj/tHylpxRqQmj0iWxGE0JAQm8Fgh0ELLgqAPzIcqyQaRy+Ku6+/9J+OQRvhyvwLzi6IXLZye7iiAIOwRIIf336PlLs7YjX+BEK/yLJURu6TXdZGaY0lTEYTSTygWsmRFusnd5f12ls= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789889981; c=relaxed/simple; bh=V5dU2utuvWxAnh5kD0Ml9zAueFHozgZpnSwIwIhjUBU=; h=Subject:To:Cc:From:Date:In-Reply-To:Message-ID:MIME-Version: Content-Type; b=azK69cp7g9FgPOcH6QES+83S5944okUXY+Jgv/+qC1Y1R9ew8P2vbhmJhCl3H2NFLrXOmsVg3GgwW3D3lTmaXNpMtRa9CtcF8Tg/e22Br7PprKF2Qjp2WeKGSBcL6lTOBRJIm8MjztalGCVNVJc0V10Rv/0zQCEXtu+8JBaUUAk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EGfynKhd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EGfynKhd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED16B1F000FF; Sun, 20 Sep 2026 07:39:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789889979; bh=XaCJpuTpJaeWWprvfAeXFlPXkQ+66/8tXLm8G9xHQbM=; h=Subject:To:Cc:From:Date:In-Reply-To; b=EGfynKhdYii8K1D1KX7/dE/qiPANaWxzJ26GhH7zn1yQR/8wGBbpzcFfR1psBO2fT rtJjUL4s0vo4Vjydetl97Vt6uocuGW0DFq5+Ta6bz4sbrQ8rKpHSSoaKlEo1sWtLt1 2RkwwJPBfaYPgCfqSyUoMTVjICxpD6R/NA9dWDzQ= Subject: Patch "mptcp: avoid unneeded actions on subflow reset" has been added to the 5.10-stable tree To: gregkh@linuxfoundation.org,kuba@kernel.org,matttbe@kernel.org,mptcp@lists.linux.dev,pabeni@redhat.com,sashal@kernel.org,xinyang@anthropic.com Cc: From: Date: Sun, 20 Sep 2026 09:36:31 +0200 In-Reply-To: <20260919204002.2106015-7-matttbe@kernel.org> Message-ID: <2026092031-backrest-duplex-fe13@gregkh> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-stable: commit X-Patchwork-Hint: ignore Content-Type: text/plain; charset="utf-8" This is a note to let you know that I've just added the patch titled mptcp: avoid unneeded actions on subflow reset to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=3Dlinux/kernel/git/stable/stable-queue.git= ;a=3Dsummary The filename of the patch is: mptcp-avoid-unneeded-actions-on-subflow-reset.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. From stable+bounces-338616-greg=3Dkroah.com@vger.kernel.org Sat Sep 19 22:4= 0:25 2026 From: "Matthieu Baerts (NGI0)" Date: Sat, 19 Sep 2026 22:40:05 +0200 Subject: mptcp: avoid unneeded actions on subflow reset To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.o= rg Cc: Paolo Abeni , sashal@kernel.org, Xinyang Ge , "Matthieu Baerts (NGI0)" , Jakub Kicin= ski Message-ID: <20260919204002.2106015-7-matttbe@kernel.org> From: Paolo Abeni commit 2b0f561f21b27c40c91ea4975268a06092bd7e9c upstream. Once in a blue moon, the mptcp receive path can recursively call mptcp_data_ready() via state change under unlucky error conditions, and then try to hold the data lock again. Break the recursion loop explicitly checking for the exceptional condition. Add a new flag instead of using an existing one like 'closing', to exit early in subflow_state_change(), and explicitly flush the RX queue at reset time. This avoids unneeded processing to check for available data -- calling get_mapping_status() and more on a dying subflow -- but also in error reporting and worker scheduling. Note that we must consume the currently peeked skb before invoking mptcp_dss_corruption to avoid consuming it again after the eventual reset has freed it. Fixes: e32d262c89e2 ("mptcp: handle consistently DSS corruption") Cc: stable@vger.kernel.org Reported-by: Xinyang Ge Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-1-0= cf5c72667c8@kernel.org Signed-off-by: Jakub Kicinski [ Note: conflict in protocol.c, because commit e0ca4057e0ec ("mptcp: micro-optimize __mptcp_move_skb()") is not in this version, and is part of a consequent rx path refactor. The conflict is in the context, and is easy to resolve, "done =3D true" can be moved along without consequences. Also, the context is slightly different because there is no DEBUG_NET_WARN_ON_ONCE in this version, see the backport commit 12c1676d598e ("mptcp: handle consistently DSS corruption"). Also a conflict in protocol.h, because __unused is at a different number. Decrement the one from this version and add the new flag above. The context is also a bit different with data_avail being an enum, but that's without consequences here. Also a conflict in subflow.c, because commit 71154bbe4942 ("mptcp: fallback earlier on simult connection") was not needed in this version, and cause conflicts in the context, but that's without consequences here. Also, a conflict in the context, because commit 81c1d0290160 ("mptcp: consolidate fallback and non fallback state machine") was not needed in this version. ] Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Greg Kroah-Hartman --- net/mptcp/protocol.c | 6 +++--- net/mptcp/protocol.h | 3 ++- net/mptcp/subflow.c | 11 +++++++++++ 3 files changed, 16 insertions(+), 4 deletions(-) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -581,11 +581,11 @@ static bool __mptcp_move_skbs_from_subfl if (unlikely(map_remaining < len)) mptcp_dss_corruption(msk, ssk); } else { - if (unlikely(!fin)) - mptcp_dss_corruption(msk, ssk); - sk_eat_skb(ssk, skb); done =3D true; + + if (unlikely(!fin)) + mptcp_dss_corruption(msk, ssk); } =20 WRITE_ONCE(tp->copied_seq, seq); --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -314,7 +314,8 @@ struct mptcp_subflow_context { mpc_map : 1, backup : 1, rx_eof : 1, - can_ack : 1; /* only after processing the remote a key */ + can_ack : 1, /* only after processing the remote a key */ + resetting : 1; /* subflow is resetting */ enum mptcp_data_avail data_avail; u32 remote_nonce; u64 thmac; --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -282,6 +282,10 @@ void mptcp_subflow_reset(struct sock *ss /* must hold: tcp_done() could drop last reference on parent */ sock_hold(sk); =20 + subflow->resetting =3D 1; + + /* No need to delay the actual close for to-be discarded data. */ + __skb_queue_purge(&ssk->sk_receive_queue); tcp_send_active_reset(ssk, GFP_ATOMIC); tcp_done(ssk); if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags) && @@ -1302,6 +1306,13 @@ static void subflow_state_change(struct =20 __subflow_state_change(sk); =20 + /* Rx queue processing is unneeded, error reporting will take place at + * __mptcp_close_ssk() time and subflow reset can't happen in case of + * fallback: subflow_sched_work_if_closed() would be a no-op. + */ + if (subflow->resetting) + return; + if (subflow_simultaneous_connect(sk)) { mptcp_do_fallback(sk); mptcp_rcv_space_init(mptcp_sk(parent), sk); Patches currently in stable-queue which might be from matttbe@kernel.org are queue-5.10/mptcp-hold-mptcp-socket-before-calling-tcp_done.patch queue-5.10/mptcp-syncookies-remember-the-request-backup-flag.patch queue-5.10/mptcp-close-race-between-scheduler-and-state-change.patch queue-5.10/mptcp-avoid-unneeded-actions-on-subflow-reset.patch