From nobody Sun Mar 22 10:12:07 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 5C58735A389 for ; Tue, 17 Mar 2026 09:13:42 +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=1773738822; cv=none; b=HjJwLJpNx/PjgQVLn/VEb6BqWIXZsg0Z66axJV+xkPRDLhE5Xy3K02vWaYjTYw6UWKN+jgFX5qw6CRsrUU/3LF0K2RN4kPZBH56ZfEMb91VzGVkTnzEi7IMEqv22tYao51eRBDUJZVd9P3Xv/1gzSGwyYEiniUNrABaUHL3ofqk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773738822; c=relaxed/simple; bh=+YJMWzBa+SbUbHxydiURNRfqH3ZTcgWPX4vlh9xC+/g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ULwUQccSghnMqNzzy5vBFVwSFUYxyLrHbP9OQdDWwVZ2qxZPhT0uSpV/CMDXPVo1+t6V5C4R0lXzxM69ExCzJNQiwLI1FB80Upt73UrHjku97DA+B7mttdtNyntfb9nhlMg2Anj9uJg5NpcTWtQzLYwqxnBkvGji5EheIwiI8Ns= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q7DHi0ZP; 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="q7DHi0ZP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18082C19425; Tue, 17 Mar 2026 09:13:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773738822; bh=+YJMWzBa+SbUbHxydiURNRfqH3ZTcgWPX4vlh9xC+/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q7DHi0ZPJgnS2vRk5QfUbUo0R+cwzu/6iw/uEb6D1Gqba3jHddS4iakB97k2JhvAM ePpN83nJdhGmPHKQX7h66aWqQihC3g7Uq/vB6t3g3Plbrvh29gdpZ98YXbkBNcD6h0 +3B1ZhU2KP5kEp6uE8aGxEiiJByrdNVseSTe0LviRh2XkL6Q92l+ikS012LuRL7frl OZCHrczKND4RcbIILwNmm0uyQpBdAbX2/zPLsf+Gp/+QsyEQYvviSO4MX/gbrjBC/h 3wD3+hOC+B0RuEBkSYiIdBWyyFyI1blaJ480BsUOSyaDsbzR+h0ls1XEMXpt0Kl452 Ysc0OS3tPNgFA== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang , Gang Yan Subject: [RFC mptcp-next v10 05/14] mptcp: avoid sleeping in read_sock path under softirq Date: Tue, 17 Mar 2026 17:12:41 +0800 Message-ID: X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Geliang Tang When mptcp_read_sock() is called from softirq context via TLS read_sock, lock_sock_fast() in mptcp_rcv_space_adjust() and mptcp_cleanup_rbuf() may trigger might_sleep() warnings or illegal sleeps, as softirq context cannot block. Replace lock_sock_fast() with spin_trylock_bh() to make locking non-blocking and context-safe. Skip operations if the lock cannot be acquired. Also introduce mptcp_data_trylock() in mptcp_move_skbs() to make data locking non-blocking in the read_sock path. Co-developed-by: Gang Yan Signed-off-by: Gang Yan Signed-off-by: Geliang Tang --- net/mptcp/protocol.c | 21 +++++++++++---------- net/mptcp/protocol.h | 1 + 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 5585f43cf879..1903f5b1fc44 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -561,12 +561,11 @@ static void mptcp_send_ack(struct mptcp_sock *msk) =20 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk, int copied) { - bool slow; - - slow =3D lock_sock_fast(ssk); - if (tcp_can_send_ack(ssk)) + if (!spin_trylock_bh(&ssk->sk_lock.slock)) + return; + if (!sock_owned_by_user(ssk) && tcp_can_send_ack(ssk)) tcp_cleanup_rbuf(ssk, copied); - unlock_sock_fast(ssk, slow); + spin_unlock_bh(&ssk->sk_lock.slock); } =20 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_em= pty) @@ -2194,14 +2193,15 @@ static void mptcp_rcv_space_adjust(struct mptcp_soc= k *msk, int copied) */ mptcp_for_each_subflow(msk, subflow) { struct sock *ssk; - bool slow; =20 ssk =3D mptcp_subflow_tcp_sock(subflow); - slow =3D lock_sock_fast(ssk); + if (!spin_trylock_bh(&ssk->sk_lock.slock)) + continue; /* subflows can be added before tcp_init_transfer() */ - if (tcp_sk(ssk)->rcvq_space.space) + if (!sock_owned_by_user(ssk) && + tcp_sk(ssk)->rcvq_space.space) tcp_rcvbuf_grow(ssk, copied); - unlock_sock_fast(ssk, slow); + spin_unlock_bh(&ssk->sk_lock.slock); } } =20 @@ -2299,7 +2299,8 @@ static bool mptcp_move_skbs(struct sock *sk) bool enqueued =3D false; u32 moved; =20 - mptcp_data_lock(sk); + if (!mptcp_data_trylock(sk)) + return false; while (mptcp_can_spool_backlog(sk, &skbs)) { mptcp_data_unlock(sk); enqueued |=3D __mptcp_move_skbs(sk, &skbs, &moved); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index f0eaba2c61fa..7d8531837736 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -378,6 +378,7 @@ struct mptcp_sock { }; =20 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock) +#define mptcp_data_trylock(sk) spin_trylock_bh(&(sk)->sk_lock.slock) #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock) =20 #define mptcp_for_each_subflow(__msk, __subflow) \ --=20 2.53.0