From nobody Fri Sep 25 10:03:49 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 D763F336897; Sat, 19 Sep 2026 19:36:06 +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=1789846568; cv=none; b=kxSzHHyhhrzSEMrwCD2LG8fh4vSSDUWoZE0W+GrhohAUOBHZlPuTZE2sudnxNCyKck7j18VEqp9nv52DoU+TG2EjLXwGsWXEYO/aCXVaSeiiq2/M4o6Va7nIgVaNluUQpRijUchfqqD1fwpj4KYEEpKfV5LOkwXJnlePeq7rsbA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789846568; c=relaxed/simple; bh=64yr2ptnBKwwopoQraamuN2FYD8M+7DAMlYze76o7Zc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mUighys9/Ey3miW7r2UNRD13cqLusg7LSvtFH9gOagIW0ucm51IlGBAcEzlF199x5GUVOgPoCAcG5MMyhOhcoS/MwjLOZq9sk4aVh7sUClV0MTsD3RMm0FfyWZcZcrHlxgwNmZmijiT68DRVQ7PTRqI1Gw/4XaGFRndMb1XUo6g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SGhYTSB/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SGhYTSB/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4072D1F00893; Sat, 19 Sep 2026 19:36:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789846566; bh=AlY+6k5FqWmdxj4slC2j+3BHD2CGbBQ7czBiDquDCdk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SGhYTSB/+58zyhM/D9WVbj7dmwRECOxoxukcHmT0DA4JE2pTfx3HxuX1jfB858yNm hmThA6XhSePsvftKU9DEercM9DHBw7Ytg1qhCBfxGQR9PL+q0jx6ywqa+u7paDpupj JmpF6QdLlbyjQ/9ybfkHamMHNkt/m+64OF2rrxzzd9PehNsdSfRoJ4HUqcsYo3DaJr DZbhKdRQxV/PnaLhe7G5YEVofW/Dy45XpRV8OzMqfwQ0Jjh4Cm7Rml5SSCbRZmbgXt dGpEs+5BjVbNRQY8oMvg9p2QqvUlDnrw/mUf4/p25igAaZ+SAU+sKEVg4rixTNa4RN 6J36mNjPxIt2Q== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 7.2.y 1/4] mptcp: move the stale logic out of retrans scheduler Date: Sat, 19 Sep 2026 21:35:43 +0200 Message-ID: <20260919193541.1915297-7-matttbe@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260919193541.1915297-6-matttbe@kernel.org> References: <20260919193541.1915297-6-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6283; i=matttbe@kernel.org; h=from:subject; bh=4ra5wgrMNu2VHjaEsJuIxYsyaDZ8HfpHsi2rjh9Y94M=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGLLWPeHzVJ59UGUV17/IGL2FYXHX0h478t9k4ZeatPmvy usq/d/vO0pZGMS4GGTFFFmk2yLzZz6v4i3x8rOAmcPKBDKEgYtTACbiVsTwP2cDu9nBvJs8tsVR GbWsZoUJJz9tiuOau2/RjtObjoeXRjP8U1sh7uKw5U8/y5kjxsbvBKTeH1gUkXXVi+Nq0C3t5z+ TmQA= X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni commit 6cafe51e0f98fe60a106783d30b2f4c4b6039f4c upstream. This allow separating the stale logic invocation and the retrans scheduler, and will simplify the next patch. It's also a cleaner design as the retrans scheduler has currently too many side effects. As a possible downside, the retrans work will now traverse the subflows list additional times; that does not matter much, as this is slowpath. While at it, pick more accurate names for the involved helpers and explicitly note that the per subflow stale data is under msk socket lock protection. The scheduler and the stale logic may observe different subflow statues, as no subflow lock is acquired. This is intentional and not harmful, worst case leading to slower retransmissions. Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260807-net-next-mptcp-oooq-pruning-v3-2-db= c1eb853cc3@kernel.org Signed-off-by: Jakub Kicinski Stable-dep-of: 2b0f561f21b2 ("mptcp: avoid unneeded actions on subflow rese= t") Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/pm.c | 41 +++++++++++++++++++++++++++-------------- net/mptcp/protocol.c | 4 ++-- net/mptcp/protocol.h | 11 +++++++---- 3 files changed, 36 insertions(+), 20 deletions(-) diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 4e1d65083b24..79bf88ca033b 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -1065,7 +1065,8 @@ bool mptcp_pm_is_backup(struct mptcp_sock *msk, struc= t sock_common *skc) return mptcp_pm_nl_is_backup(msk, &skc_local); } =20 -static void mptcp_pm_subflows_chk_stale(const struct mptcp_sock *msk, stru= ct sock *ssk) +static void +mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk) { struct mptcp_subflow_context *iter, *subflow =3D mptcp_subflow_ctx(ssk); struct sock *sk =3D (struct sock *)msk; @@ -1102,22 +1103,34 @@ static void mptcp_pm_subflows_chk_stale(const struc= t mptcp_sock *msk, struct soc } } =20 -void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock = *ssk) +void mptcp_pm_chk_stale(const struct mptcp_sock *msk) { - struct mptcp_subflow_context *subflow =3D mptcp_subflow_ctx(ssk); - u32 rcv_tstamp =3D READ_ONCE(tcp_sk(ssk)->rcv_tstamp); + struct mptcp_subflow_context *subflow; =20 - /* keep track of rtx periods with no progress */ - if (!subflow->stale_count) { - subflow->stale_rcv_tstamp =3D rcv_tstamp; - subflow->stale_count++; - } else if (subflow->stale_rcv_tstamp =3D=3D rcv_tstamp) { - if (subflow->stale_count < U8_MAX) + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk =3D mptcp_subflow_tcp_sock(subflow); + u32 rcv_tstamp; + + if (!__mptcp_subflow_active(subflow)) + continue; + + /* No data outstanding at TCP level? not stale */ + if (tcp_rtx_and_write_queues_empty(ssk)) + continue; + + /* keep track of rtx periods with no progress */ + rcv_tstamp =3D READ_ONCE(tcp_sk(ssk)->rcv_tstamp); + if (!subflow->stale_count) { + subflow->stale_rcv_tstamp =3D rcv_tstamp; subflow->stale_count++; - mptcp_pm_subflows_chk_stale(msk, ssk); - } else { - subflow->stale_count =3D 0; - mptcp_subflow_set_active(subflow); + } else if (subflow->stale_rcv_tstamp =3D=3D rcv_tstamp) { + if (subflow->stale_count < U8_MAX) + subflow->stale_count++; + mptcp_pm_subflow_chk_stale(msk, ssk); + } else { + subflow->stale_count =3D 0; + mptcp_subflow_set_active(subflow); + } } } =20 diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 97523fa284d5..6db944b5c423 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2471,7 +2471,6 @@ struct sock *mptcp_subflow_get_retrans(struct mptcp_s= ock *msk) =20 /* still data outstanding at TCP level? skip this */ if (!tcp_rtx_and_write_queues_empty(ssk)) { - mptcp_pm_subflow_chk_stale(msk, ssk); min_stale_count =3D min_t(int, min_stale_count, subflow->stale_count); continue; } @@ -2803,9 +2802,10 @@ static void __mptcp_retrans(struct sock *sk) int ret, err; u16 len =3D 0; =20 + mptcp_pm_chk_stale(msk); + mptcp_clean_una_wakeup(sk); =20 - /* first check ssk: need to kick "stale" logic */ err =3D mptcp_sched_get_retrans(msk); dfrag =3D mptcp_rtx_head(sk); if (!dfrag) { diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index dbb40295165b..825533614468 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -581,12 +581,11 @@ struct mptcp_subflow_context { remote_key_valid : 1, /* received the peer key from */ disposable : 1, /* ctx can be free at ulp release time */ closing : 1, /* must not pass rx data to msk anymore */ - stale : 1, /* unable to snd/rcv data, do not use for xmit */ 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 */ - __unused : 8; + __unused : 9; bool data_avail; bool scheduled; bool pm_listener; /* a listener managed by the kernel PM? */ @@ -605,7 +604,11 @@ struct mptcp_subflow_context { u8 reset_seen:1; u8 reset_transient:1; u8 reset_reason:4; - u8 stale_count; + u8 stale_count; /* Protected by the msk socket lock */ + u8 stale; /* Protected by the msk socket lock, + * if set the subflow is unable to snd/rcv + * data, the schedule should skip it + */ =20 u32 subflow_id; =20 @@ -1104,7 +1107,7 @@ int mptcp_pm_parse_entry(struct nlattr *attr, struct = genl_info *info, bool mptcp_pm_addr_families_match(const struct sock *sk, const struct mptcp_addr_info *loc, const struct mptcp_addr_info *rem); -void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock = *ssk); +void mptcp_pm_chk_stale(const struct mptcp_sock *msk); void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ss= k, int server_side); void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock = *ssk); bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk); --=20 2.55.0 From nobody Fri Sep 25 10:03:49 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 D424A35FF6C; Sat, 19 Sep 2026 19:36:08 +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=1789846570; cv=none; b=Q0tdP9Ui3MTYVMF/XTH4PGsT5Wgkal93DFu2/b4/7OUNHZAZkWJOs0NEevssL4JX7pwX8+kzLDs9KfXc1XAjtLLraSDeyE0vxtTTALWxp632ZxAHD1GRAVquZ0cXulrRysJORl81yj03dDtzJ75GqemhUxFE1/N2aM3qVzq53TI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789846570; c=relaxed/simple; bh=/zyBhep2tMYKrPaNAHIGYIl40eFmKLj8No/Z6mxW1N8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CKnVHpBPGIVABn8i8ZkOwyPFunPwQbG8TlxmgHwUd3O0ae/iQSzXLGzUoRSVghcl8ySUsEmgasO3GdB9PJ+76Td0b2bkt75QXnPAC8KytGge2sTOXVtO/6HPoZyabLHtoGIf2CLNheris3GHm4O9/W4vxy7T3hLux5cXURD0kmI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Lg09bk/E; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Lg09bk/E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3E231F00898; Sat, 19 Sep 2026 19:36:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789846568; bh=c4TeFYzXb2H8L3hwwqpe+jEoL2EFuS6ojdVr9hrJqFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Lg09bk/Ew8KwRVHgDLE12V/2UYWpipQKKA9W6t7vyo/6il9DtIg8qECX1kIDkfSbB p3+BGx/KgWJR9X448+aHi7K+O+4EQqkHLn+QlNOF/b2ugIGXJlhV5MyAacDUgiN73Z NzFJe/A3KLDz1uYjN+I/Up/y/68UtDF10Xq97aP3+jFMV+bZrc8MsNcj+jfNhDJJYO aeasneBGk4Sfs/R6xk8M0jD68IC60aL7LzLABEqi8y7sf3QKfSd+u2UwQBV/IybCZC PpRRXXNriVBiQVN3YyIyQfNUKbqisx5Vol+VAO1dFXwosziur3Ln5mc6ueNHjVyElW YH6l9Pv8Q9WYA== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, Xinyang Ge , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 7.2.y 2/4] mptcp: avoid unneeded actions on subflow reset Date: Sat, 19 Sep 2026 21:35:44 +0200 Message-ID: <20260919193541.1915297-8-matttbe@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260919193541.1915297-6-matttbe@kernel.org> References: <20260919193541.1915297-6-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3752; i=matttbe@kernel.org; h=from:subject; bh=AVrDwnrVWRrcQWUftTQ0Y0xp0+rHHcsERJzquA85cwI=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGLLWPRFwsdI43n67s2u6QHOUQnbSv/W/Im4FKn534SvjU WVa7Dulo5SFQYyLQVZMkUW6LTJ/5vMq3hIvPwuYOaxMIEMYuDgFYCLy8xj+J0XN2rNvxiu5sDf2 tXHNr5Vfht2Rbnn+7DhXkKFi/qYETkaGzTNSf21/cytp6m1jz4MfvsisPbfRunBvyKzA1zvea/z K4QIA X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 4 ++-- net/mptcp/protocol.h | 3 ++- net/mptcp/subflow.c | 11 +++++++++++ 3 files changed, 15 insertions(+), 3 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 6db944b5c423..b6581858979d 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -773,12 +773,12 @@ static bool __mptcp_move_skbs_from_subflow(struct mpt= cp_sock *msk, mptcp_dss_corruption(msk, ssk); } } else { + sk_eat_skb(ssk, skb); + if (unlikely(!fin)) { DEBUG_NET_WARN_ON_ONCE(1); mptcp_dss_corruption(msk, ssk); } - - sk_eat_skb(ssk, skb); } =20 WRITE_ONCE(tp->copied_seq, seq); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 825533614468..d44aaa783c22 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -585,7 +585,8 @@ struct mptcp_subflow_context { 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 */ - __unused : 9; + resetting : 1, /* subflow is resetting */ + __unused : 8; bool data_avail; bool scheduled; bool pm_listener; /* a listener managed by the kernel PM? */ diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index bde79720098a..edd33dc9367f 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -436,6 +436,10 @@ void mptcp_subflow_reset(struct sock *ssk) /* 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); mptcp_send_active_reset_reason(ssk); tcp_done(ssk); if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags)) @@ -1873,6 +1877,13 @@ static void subflow_state_change(struct sock *sk) =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; + /* as recvmsg() does not acquire the subflow socket for ssk selection * a fin packet carrying a DSS can be unnoticed if we don't trigger * the data available machinery here. --=20 2.55.0 From nobody Fri Sep 25 10:03:49 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 2987137C923; Sat, 19 Sep 2026 19:36:10 +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=1789846572; cv=none; b=LRK7heq/4+Fx/YBpF6eYfRaPCG/ePXLeT20fzMY07pq5RlMsBfZQLV2pQsPAOTPJjYHksWX/kb1v47fX4VnMKcfIh0LHCHQvsJs0VGbv20fI8Y3Rw5ZnnlnemYzUfbLe8/RAIlKlGUB5jvMpbCMJa4De63JmFMMN1scrapUoO4Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789846572; c=relaxed/simple; bh=CN1/SK+Y8yFbsameLPvNWaUmOIDS2T5f+NmuRjL+7hc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Bwj3VIEnl0MCvSxmgjqt8wavJqnW8zJwxE/BQGLY0KFfouE4INrzvH4NTBbzuu4FFKxZOj/nZzyz1R/LqsNVks4IsQrQg92CWY/T4PclCLXoiIjFUq9w2hfI9TD+UjYjhdk1IbHKIwff09pGMFwLB+8fMH2DAoap+3kSb5oUDGE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kz85fqWn; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kz85fqWn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D89AF1F000FF; Sat, 19 Sep 2026 19:36:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789846570; bh=5xA+FJH7GWS4YusAZCGPKyUllf//BAWDWX7tMuc6SeE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kz85fqWnWw6OCA4hFNZA1BvCgQNmnt1kpGJu7R5DgixImfLhdokvhMg6cP6DLp0ht ZVwqsWD7zpdDFGj9kKWxwpLfYkEZdYMYIbD/fEoLPpdpoA8ufxbVQj6uBWUHTtyvCl 0f2jzmeJK/rItfHUekuGVAE6pJUcPpgSA6MKEc+fTjkg5zPX2H4bAV2+A9mdQCeXwz BO/66qGm34QbETdgnYhOVTq1f22o+WRLvG0n4eLnFtQqTMiNHRrdPBFuqGrjrzJulk xaaiqE5k+Ly455NCG5Q9/KDj/ecasy0M796UTGO9GcOGYBon/diaYlEQHnic09jJsv FKNGzzOhafaKw== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, Shardul Bankar , Xinyang Ge , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 7.2.y 3/4] mptcp: close race between scheduler and state change Date: Sat, 19 Sep 2026 21:35:45 +0200 Message-ID: <20260919193541.1915297-9-matttbe@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260919193541.1915297-6-matttbe@kernel.org> References: <20260919193541.1915297-6-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1636; i=matttbe@kernel.org; h=from:subject; bh=+/aiUzZzfqJ31ICMVpIbl3dR0DbObCOaPqDPmlz8uUU=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGLLWPRH8p3ek5VnAc6kdx3tXr19TxLud4TDD7H+rpm7N5 83by/Rco6OUhUGMi0FWTJFFui0yf+bzKt4SLz8LmDmsTCBDGLg4BWAiJ8QYGRbW51fn9W0ovxn8 5rBGtQS33DK9KQXGpYuOpfntf2rjX83IcIfjVOtN7Y4ngnctRSbOeXcj8N2Vqnk1tixrc6YxhrN q8wMA X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni commit 42064de57fb83231fcc89663a94885f228a1ee53 upstream. The mptcp scheduler may race with subflow sockets state change: data transmission on the selected socket may fail and a later release could try to use mss_now reset to 0 for a divide operation. Address the issue by explicitly checking for the critical scenario. Fixes: c886d70286bf ("mptcp: do not queue data on closed subflows") Cc: stable@vger.kernel.org Reported-by: Shardul Bankar Reported-by: Xinyang Ge Closes: https://lore.kernel.org/20260525194828.1137119-1-shardul.b@mpiricso= ftware.com 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-v2-2-0= cf5c72667c8@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index b6581858979d..99fd31036222 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1588,7 +1588,9 @@ struct sock *mptcp_subflow_get_send(struct mptcp_sock= *msk) =20 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info= *info) { - tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); + if (info->mss_now) + tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, + info->size_goal); release_sock(ssk); } =20 --=20 2.55.0 From nobody Fri Sep 25 10:03:49 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 D106337F8A5; Sat, 19 Sep 2026 19:36:12 +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=1789846573; cv=none; b=Zgqr4ZDle7Fzc4jy6cQAdkY/SXLMpQ3nOMIX94B42/WAKg4MRJk90DIrsGi35V7kpijfYnQ+ACpjPSPnrWj1sDGpzIyUC9KpglkItHu+FHneq4IYMYSFfZAeUoVF/+G3B6OY594ENlSsbSulfO+ZkzuKcn/NekzvDJRgLqLwwRw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789846573; c=relaxed/simple; bh=TfzeQIK27t9eTMvzel3SPQcHoJrIpYJUvNvHcZjvPX4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NbqnDuiWj0xaV+6J/9ha3JQOtaAvEnSM81na4C9p1CAevEd/gUAA2p5W3r9kOWxHco5S/csdCXIJ/HPUCh+ONUC/AMe3/XTloIOBXXI5X6WFOuvI27lsFCcRf+1NTGVAGkSRpZHZoEV5z2SdR/f0bWX+svXOg8sXP/qJr1zJwQw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WwagS/xv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WwagS/xv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E19AC1F00893; Sat, 19 Sep 2026 19:36:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789846572; bh=/dX5RDRjuPPB5D4Lt8fvfZHMKwejWXrmXHGsU3a20XQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WwagS/xvImXe2SocOgT6DkW1pafutUR0vXfX/UyyN80FuwI26YKk4YmKodBGR0lmn qHKg99hNz7WZjghe7zxfXr6oqouJBopQ3RRTmR1NZYbxkSdRK8zmGqOtRXuv2Ripbk vfBgVNITO8YEAb15JKI96N3+IWQzgVCdTe9HX682UB9L22PY9VhsQu8kJECXEynbR1 cuO8rsxFO0YLPc3WvYrEqdztWM2LnBCavhz3GZmQaexcBI56CCnWGNdMSKE22z2Mmz M0mUal7G5rS+cuvwTc1AS6B/8TCTFrE+1TSDTRHwwuTj5gsRB/Cc0bT5A79kHqV3dz TpXk4iRLqnOqA== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 7.2.y 4/4] mptcp: fix bad accounting in __mptcp_subflow_push_pending() Date: Sat, 19 Sep 2026 21:35:46 +0200 Message-ID: <20260919193541.1915297-10-matttbe@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260919193541.1915297-6-matttbe@kernel.org> References: <20260919193541.1915297-6-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1208; i=matttbe@kernel.org; h=from:subject; bh=CBGyH42FD8cIrT1KBwusD3qZxSa0CQyV0XC8tYc+c4Q=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGLLWPRH6ris2Xex2c82BPblHPxeWRDpffhcsNYf99dK4p pJFN9be7yhlYRDjYpAVU2SRbovMn/m8irfEy88CZg4rE8gQBi5OAZiIWQ3D/7AtdfvCHVP0WYX4 vuTMTSjfUz+va9KBneW/ktuWslr9msTwz6TNtaL+afK3i8n3SrdqSfjlfSuZtG3qHPs975ne/dn 8mwcA X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni commit f3ef03357396d4b147d8e76c75fb612c2f264ffc upstream. If __subflow_push_pending() errors out we should avoid updating the copied byte counters, to avoid mismatch push call later on. Fixes: 0fa1b3783a17 ("mptcp: use get_send wrapper") 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/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-3-0= cf5c72667c8@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 99fd31036222..49c46498af96 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1778,7 +1778,8 @@ static void __mptcp_subflow_push_pending(struct sock = *sk, struct sock *ssk, bool ret =3D __subflow_push_pending(sk, ssk, &info); if (ret <=3D 0) keep_pushing =3D false; - copied +=3D ret; + else + copied +=3D ret; } =20 mptcp_for_each_subflow(msk, subflow) { --=20 2.55.0