From mboxrd@z Thu Jan 1 00:00:00 1970 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 81A1A1ABECB; Wed, 23 Oct 2024 12:19:50 +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=1729685990; cv=none; b=KpNuaY1avgEzq9haPx3YPU32JrIb2iUy/15yQByjMRc6bBHj7aNQP6AiqmkRLrM/PVMmITfczLC4gg+zoRMsX2GStAlhhmg2c1eHpnTo5aX/07beQBaE8ZMG55CywH/4G5ljbE5jJY4qUnjVE2R5ZYf3Z42lj099NupEvyFzbMQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729685990; c=relaxed/simple; bh=bHmIRav5p78QXwL8NtAQtzKAhGl1hwjcHaW1KtdCIZE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fZcpK/0KlqvHETZ1nz7Qclhn4hNqfYfpouspeEDmVoYogmWkSqO8Glc7G+LBUUZFRyHAYNP96TzkMfb7LMa5cML/O6tzk34WKiPnZqZl/8dg6rHl8MK90qpuNxUkVK8TCVzp6bAYOOy/XWHv+yBpiueqEtA9B5Afj3YXTgxzepc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Jmv2n/8r; 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="Jmv2n/8r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 514EBC4CEC6; Wed, 23 Oct 2024 12:19:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729685990; bh=bHmIRav5p78QXwL8NtAQtzKAhGl1hwjcHaW1KtdCIZE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Jmv2n/8ryIThzxNHVTxpMfjpG8uVOugDTv0SpVyYn5mqpZFvF7ce5/ZtUjE1CK+kx F0jv8YvMQ0p+g6e4jZY9rpsYWSRkf8MoNq5yTl5PC5cXTsjDHxsaf5u01cJjNooJbl jiN7BmCwYcFVuBujNne6upnsofEAHEpMRXLMiYZ0Pn+ddLPVdBkBL9+kN3ca13ceOf j5tPtewiAotnsedeIezPj2n+y2X+WOWOKU+PxO1tiGMN9sIlkhwHezEynZry5giU+j Q6v1+7x/5BeaojvXFEqV7iDGYLvN9lhQWUq/7MqYBlCVlZJjinXrZGW8F0LU2sX12l qF1j/Jd+bpcuA== Date: Wed, 23 Oct 2024 13:19:45 +0100 From: Simon Horman To: "Matthieu Baerts (NGI0)" Cc: mptcp@lists.linux.dev, Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Gregory Detal , Shuah Khan , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH net 1/3] mptcp: init: protect sched with rcu_read_lock Message-ID: <20241023121945.GS402847@kernel.org> References: <20241021-net-mptcp-sched-lock-v1-0-637759cf061c@kernel.org> <20241021-net-mptcp-sched-lock-v1-1-637759cf061c@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241021-net-mptcp-sched-lock-v1-1-637759cf061c@kernel.org> On Mon, Oct 21, 2024 at 12:25:26PM +0200, Matthieu Baerts (NGI0) wrote: > Enabling CONFIG_PROVE_RCU_LIST with its dependence CONFIG_RCU_EXPERT > creates this splat when an MPTCP socket is created: > > ============================= > WARNING: suspicious RCU usage > 6.12.0-rc2+ #11 Not tainted > ----------------------------- > net/mptcp/sched.c:44 RCU-list traversed in non-reader section!! > > other info that might help us debug this: > > rcu_scheduler_active = 2, debug_locks = 1 > no locks held by mptcp_connect/176. > > stack backtrace: > CPU: 0 UID: 0 PID: 176 Comm: mptcp_connect Not tainted 6.12.0-rc2+ #11 > Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > Call Trace: > > dump_stack_lvl (lib/dump_stack.c:123) > lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822) > mptcp_sched_find (net/mptcp/sched.c:44 (discriminator 7)) > mptcp_init_sock (net/mptcp/protocol.c:2867 (discriminator 1)) > ? sock_init_data_uid (arch/x86/include/asm/atomic.h:28) > inet_create.part.0.constprop.0 (net/ipv4/af_inet.c:386) > ? __sock_create (include/linux/rcupdate.h:347 (discriminator 1)) > __sock_create (net/socket.c:1576) > __sys_socket (net/socket.c:1671) > ? __pfx___sys_socket (net/socket.c:1712) > ? do_user_addr_fault (arch/x86/mm/fault.c:1419 (discriminator 1)) > __x64_sys_socket (net/socket.c:1728) > do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1)) > entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) > > That's because when the socket is initialised, rcu_read_lock() is not > used despite the explicit comment written above the declaration of > mptcp_sched_find() in sched.c. Adding the missing lock/unlock avoids the > warning. > > Fixes: 1730b2b2c5a5 ("mptcp: add sched in mptcp_sock") > Cc: stable@vger.kernel.org > Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/523 > Reviewed-by: Geliang Tang > Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Simon Horman