From nobody Wed Jun 24 09:24:50 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6A0B73D75C3 for ; Mon, 13 Apr 2026 14:12:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776089530; cv=none; b=hnOc0qe0bd98WwdFChFU6W2TEfaUK00usJNOAn2BPWKMdjxsE6IpaSZTSHKSn53oZxOFDD+Sr2u/c96GJrKe+3muvvFrjMWRO9NoCNYSdn08KN2OyEJNeqZKAgZ+GOvTTS0zFHcWlR61GeKav/gRY5dgCw5gu+QYH0XIh/VeQic= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776089530; c=relaxed/simple; bh=GnVcK+k6p55UYcQNlYBgs9oGPxvxqm9Qo+2p6Q0pZk4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=p8/ED6r4SkEl5Hn1WTE2XyYFEV93K6s5ORrc93JdSDtqlrFDln95eEDl7AuwRGPwRN4jwQkrxAxT6yULM5V7fAZwroquIOo132k4CWzRMeh1ApdXuAUkURR8uTHxU1mxtMhkm929Kz0sq7oquxIrNsGO60Cm4+7fAZQTIz8qm7A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pzr9WIjH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pzr9WIjH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC1FDC2BCB5; Mon, 13 Apr 2026 14:12:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776089530; bh=GnVcK+k6p55UYcQNlYBgs9oGPxvxqm9Qo+2p6Q0pZk4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=pzr9WIjH4IpdfbLzwB3ebofO9oG8BoeuHaZVLsUrc3iFEUcf4aGnaSdKBOF0DVOwX Wz971RssjvJUC48DpkxW6wKB9/KeDPYrGTzQtidyHT3kpTCn1vrF2CfyVR44HmVenV GbVcb9jGgRARH7V5Vz3jfTGuyK38JWzEy3RS9cjP4C91keovn8uhJ/w7w+NW0KMbpA zZE7N+JFsPB/L2sRaWbTSpCv1X0ipt0sV70rS1QbW0LArYl43zsP92o9KM5pOEam1d onIJwHMVtnCjv7FfrHCfoflBmsNBEPGvmJjc+MtiZEhEGvMLFEllfK8UG8tiWuOso5 4e4LEQaVSMVDQ== From: "Matthieu Baerts (NGI0)" Date: Mon, 13 Apr 2026 16:11:51 +0200 Subject: [PATCH mptcp-net v3 05/19] mptcp: pm: ADD_ADDR rtx: free sk if last Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260413-mptcp-inc-limits-v3-5-dd36c9360432@kernel.org> References: <20260413-mptcp-inc-limits-v3-0-dd36c9360432@kernel.org> In-Reply-To: <20260413-mptcp-inc-limits-v3-0-dd36c9360432@kernel.org> To: MPTCP Upstream Cc: "Matthieu Baerts (NGI0)" X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3597; i=matttbe@kernel.org; h=from:subject:message-id; bh=GnVcK+k6p55UYcQNlYBgs9oGPxvxqm9Qo+2p6Q0pZk4=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGDLv/FzN8tZps44tz4GrR5yE9J1eH7s5d8p37nUHg7d1L JK6qPO6saOUhUGMi0FWTJFFui0yf+bzKt4SLz8LmDmsTCBDGLg4BWAiHqEM/9QO2y1hORZ7Y++7 VX8KF5+3a1j42/Dd022/z9yPOPDk8ZrHDP8rTok9jbXXDFPunfAn8fVZiQmFcxV3d7UvyotV9Hg 1czYPAA== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 When an ADD_ADDR is retransmitted, the sk is held in sk_reset_timer(), and released at the end. If at that moment, it was the last reference being held, the sk would not be freed. sock_put() should then be called instead of __sock_put(). But that's not enough: if it is the last reference, sock_put() will call sk_free(), which will end up calling sk_stop_timer_sync() on the same timer, and waiting indefinitely to finish. So it is needed to mark that the timer is done, and no need to call sk_stop_timer_sync(). Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Signed-off-by: Matthieu Baerts (NGI0) --- v3: support calling sk_free() from the timer handler. Note: I'm not very happy with this patch, it looks too big. Did I miss a simpler way? --- net/mptcp/pm.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index d3fcf441b208..adbebf46dcce 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -16,6 +16,7 @@ struct mptcp_pm_add_entry { struct list_head list; struct mptcp_addr_info addr; u8 retrans_times; + bool timer_done; struct timer_list add_timer; struct mptcp_sock *sock; struct rcu_head rcu; @@ -327,22 +328,22 @@ static void mptcp_pm_add_timer(struct timer_list *tim= er) add_timer); struct mptcp_sock *msk =3D entry->sock; struct sock *sk =3D (struct sock *)msk; - unsigned int timeout; + unsigned int timeout =3D 0; =20 pr_debug("msk=3D%p\n", msk); =20 - if (unlikely(inet_sk_state_load(sk) =3D=3D TCP_CLOSE)) - goto exit; - bh_lock_sock(sk); + if (unlikely(inet_sk_state_load(sk) =3D=3D TCP_CLOSE)) + goto out; + if (sock_owned_by_user(sk)) { /* Try again later. */ - sk_reset_timer(sk, timer, jiffies + HZ / 20); + timeout =3D HZ / 20; goto out; } =20 if (mptcp_pm_should_add_signal_addr(msk)) { - sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8); + timeout =3D TCP_RTO_MAX / 8; goto out; } =20 @@ -360,8 +361,9 @@ static void mptcp_pm_add_timer(struct timer_list *timer) } =20 if (entry->retrans_times < ADD_ADDR_RETRANS_MAX) - sk_reset_timer(sk, timer, - jiffies + (timeout << entry->retrans_times)); + timeout <<=3D entry->retrans_times; + else + timeout =3D 0; =20 spin_unlock_bh(&msk->pm.lock); =20 @@ -369,9 +371,13 @@ static void mptcp_pm_add_timer(struct timer_list *time= r) mptcp_pm_subflow_established(msk); =20 out: + if (timeout) + sk_reset_timer(sk, timer, jiffies + timeout); + else + /* if sock_put calls sk_free: avoid waiting for this timer */ + entry->timer_done =3D true; bh_unlock_sock(sk); -exit: - __sock_put(sk); + sock_put(sk); } =20 struct mptcp_pm_add_entry * @@ -431,12 +437,15 @@ bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk, add_entry->addr =3D *addr; add_entry->sock =3D msk; add_entry->retrans_times =3D 0; + add_entry->timer_done =3D false; =20 timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0); reset_timer: timeout =3D mptcp_adjust_add_addr_timeout(msk); if (timeout) sk_reset_timer(sk, &add_entry->add_timer, jiffies + timeout); + else + add_entry->timer_done =3D true; =20 return true; } @@ -454,7 +463,8 @@ static void mptcp_pm_free_anno_list(struct mptcp_sock *= msk) spin_unlock_bh(&msk->pm.lock); =20 list_for_each_entry_safe(entry, tmp, &free_list, list) { - sk_stop_timer_sync(sk, &entry->add_timer); + if (!entry->timer_done) + sk_stop_timer_sync(sk, &entry->add_timer); kfree_rcu(entry, rcu); } } --=20 2.53.0