From patchwork Thu Feb 27 12:24:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taehee Yoo X-Patchwork-Id: 1245797 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=WNdIZwGH; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48SsLc1v0vz9sNg for ; Thu, 27 Feb 2020 23:24:56 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729004AbgB0MYz (ORCPT ); Thu, 27 Feb 2020 07:24:55 -0500 Received: from mail-pj1-f65.google.com ([209.85.216.65]:55580 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728953AbgB0MYz (ORCPT ); Thu, 27 Feb 2020 07:24:55 -0500 Received: by mail-pj1-f65.google.com with SMTP id a18so1063619pjs.5 for ; Thu, 27 Feb 2020 04:24:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=Hd0ZbJ/jgoPIR1VF33oaTk0U4UZku3XF23faOWf/9E8=; b=WNdIZwGHv/QtXB7dvkDaM4+iQhWGGVwkQ4aba/0Iy6Gio2/6Aq1JqhkHLVQNuSlt7a +/kf0JmIU3iz77ebS+JWP+zWORCg1UsfwW2N8ctf50PAGIgGJChKm2gbra6HhbsyXH4e Cib/P0NKXTOwZ3zzZMpTu1GzW91p19RleSbNbnuVRRr1bbBoagi2pmN9EobOEFuXmQ4i vXr65iC6u8kmEGnVwKlCh11ikx1uTvFZTKx88ClQKOvPeGvDUjOvffRII1Rwr0XPSS0Y hsmPxE7AtzSphm15M30wjIVzk79tZnvGHSfgeABcMB65jf0ezU9eNaYTdjL6gVma/Dzm oC2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=Hd0ZbJ/jgoPIR1VF33oaTk0U4UZku3XF23faOWf/9E8=; b=ED4PoiPQyFyVbdxaZpslyIJS8owtzAIc24FOK5X8I/pT24Ki606uUGLgznVNDvIVaW GTlKVHiwHyE9XzQH4EnAAvcHlImj2fVpvq4cmWm0PlhAWi882zDWNBV3N79bzNfN1sjc wwFly/1zJ2yQY8I6Oj4uDp4cn3150TVil1LNSB7ieZew2jylpbDEWKTko08bbm9rU6rq 2h4pIyeRtBOwbsWr/aVGiajz2AteQ02FWyvejhmNzaEhfkCC3oWIYjZ+jBpfuPmBTMtX GAUHX3DtwM2nHqzvjrmIkOqzMGbX7Vqwhal5ng9P4ZA95x1+/tj0/Rs+BIxIzKKei853 aLAg== X-Gm-Message-State: APjAAAUiA3XrEn7tHozaiRPia+cfYjGNdFiIsbqxlmN6Y6OGQndmCP42 E0Tqz3hBs0WWEOdwrAMstt4= X-Google-Smtp-Source: APXvYqzN9SqtyJrW3QTaJTUDfCjSwFewpoMcpHLTTl+xdZur25uGIccKMg7fbI+zaYorXmh+1M00JA== X-Received: by 2002:a17:90a:bd89:: with SMTP id z9mr4521141pjr.13.1582806293369; Thu, 27 Feb 2020 04:24:53 -0800 (PST) Received: from localhost.localdomain ([180.70.143.152]) by smtp.gmail.com with ESMTPSA id 190sm6590913pga.85.2020.02.27.04.24.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Feb 2020 04:24:52 -0800 (PST) From: Taehee Yoo To: davem@davemloft.net, kuba@kernel.org, subashab@codeaurora.org, stranche@codeaurora.org, netdev@vger.kernel.org Cc: ap420073@gmail.com Subject: [PATCH net v2 3/8] net: rmnet: fix suspicious RCU usage Date: Thu, 27 Feb 2020 12:24:45 +0000 Message-Id: <20200227122445.19169-1-ap420073@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org rmnet_get_port() internally calls rcu_dereference_rtnl(), which checks RTNL. But rmnet_get_port() could be called by packet path. The packet path is not protected by RTNL. So, the suspicious RCU usage problem occurs. Test commands: modprobe rmnet ip netns add nst ip link add veth0 type veth peer name veth1 ip link set veth1 netns nst ip link add rmnet0 link veth0 type rmnet mux_id 1 ip netns exec nst ip link add rmnet1 link veth1 type rmnet mux_id 1 ip netns exec nst ip link set veth1 up ip netns exec nst ip link set rmnet1 up ip netns exec nst ip a a 192.168.100.2/24 dev rmnet1 ip link set veth0 up ip link set rmnet0 up ip a a 192.168.100.1/24 dev rmnet0 ping 192.168.100.2 Splat looks like: [ 146.630958][ T1174] WARNING: suspicious RCU usage [ 146.631735][ T1174] 5.6.0-rc1+ #447 Not tainted [ 146.632387][ T1174] ----------------------------- [ 146.633151][ T1174] drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c:386 suspicious rcu_dereference_check() ! [ 146.634742][ T1174] [ 146.634742][ T1174] other info that might help us debug this: [ 146.634742][ T1174] [ 146.645992][ T1174] [ 146.645992][ T1174] rcu_scheduler_active = 2, debug_locks = 1 [ 146.646937][ T1174] 5 locks held by ping/1174: [ 146.647609][ T1174] #0: ffff8880c31dea70 (sk_lock-AF_INET){+.+.}, at: raw_sendmsg+0xab8/0x2980 [ 146.662463][ T1174] #1: ffffffff93925660 (rcu_read_lock_bh){....}, at: ip_finish_output2+0x243/0x2150 [ 146.671696][ T1174] #2: ffffffff93925660 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x213/0x2940 [ 146.673064][ T1174] #3: ffff8880c19ecd58 (&dev->qdisc_running_key#7){+...}, at: ip_finish_output2+0x714/0x2150 [ 146.690358][ T1174] #4: ffff8880c5796898 (&dev->qdisc_xmit_lock_key#3){+.-.}, at: sch_direct_xmit+0x1e2/0x1020 [ 146.699875][ T1174] [ 146.699875][ T1174] stack backtrace: [ 146.701091][ T1174] CPU: 0 PID: 1174 Comm: ping Not tainted 5.6.0-rc1+ #447 [ 146.705215][ T1174] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 146.706565][ T1174] Call Trace: [ 146.707102][ T1174] dump_stack+0x96/0xdb [ 146.708007][ T1174] rmnet_get_port.part.9+0x76/0x80 [rmnet] [ 146.709233][ T1174] rmnet_egress_handler+0x107/0x420 [rmnet] [ 146.710492][ T1174] ? sch_direct_xmit+0x1e2/0x1020 [ 146.716193][ T1174] rmnet_vnd_start_xmit+0x3d/0xa0 [rmnet] [ 146.717012][ T1174] dev_hard_start_xmit+0x160/0x740 [ 146.717854][ T1174] sch_direct_xmit+0x265/0x1020 [ 146.718577][ T1174] ? register_lock_class+0x14d0/0x14d0 [ 146.719429][ T1174] ? dev_watchdog+0xac0/0xac0 [ 146.723738][ T1174] ? __dev_queue_xmit+0x15fd/0x2940 [ 146.724469][ T1174] ? lock_acquire+0x164/0x3b0 [ 146.725172][ T1174] __dev_queue_xmit+0x20c7/0x2940 [ ... ] Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation") Signed-off-by: Taehee Yoo --- v1 -> v2: - update commit log. - remove unnecessary rcu_read_lock(). - use rcu_dereference_bh() instead of rcu_dereference(). drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c | 13 ++++++------- drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h | 2 +- .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c | 4 ++-- 3 files changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c index ac58f584190b..fc68ecdd804b 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c @@ -382,11 +382,10 @@ struct rtnl_link_ops rmnet_link_ops __read_mostly = { .fill_info = rmnet_fill_info, }; -/* Needs either rcu_read_lock() or rtnl lock */ -struct rmnet_port *rmnet_get_port(struct net_device *real_dev) +struct rmnet_port *rmnet_get_port_rcu(struct net_device *real_dev) { if (rmnet_is_real_dev_registered(real_dev)) - return rcu_dereference_rtnl(real_dev->rx_handler_data); + return rcu_dereference_bh(real_dev->rx_handler_data); else return NULL; } @@ -412,7 +411,7 @@ int rmnet_add_bridge(struct net_device *rmnet_dev, struct rmnet_port *port, *slave_port; int err; - port = rmnet_get_port(real_dev); + port = rmnet_get_port_rtnl(real_dev); /* If there is more than one rmnet dev attached, its probably being * used for muxing. Skip the briding in that case @@ -427,7 +426,7 @@ int rmnet_add_bridge(struct net_device *rmnet_dev, if (err) return -EBUSY; - slave_port = rmnet_get_port(slave_dev); + slave_port = rmnet_get_port_rtnl(slave_dev); slave_port->rmnet_mode = RMNET_EPMODE_BRIDGE; slave_port->bridge_ep = real_dev; @@ -445,11 +444,11 @@ int rmnet_del_bridge(struct net_device *rmnet_dev, struct net_device *real_dev = priv->real_dev; struct rmnet_port *port, *slave_port; - port = rmnet_get_port(real_dev); + port = rmnet_get_port_rtnl(real_dev); port->rmnet_mode = RMNET_EPMODE_VND; port->bridge_ep = NULL; - slave_port = rmnet_get_port(slave_dev); + slave_port = rmnet_get_port_rtnl(slave_dev); rmnet_unregister_real_device(slave_dev, slave_port); netdev_dbg(slave_dev, "removed from rmnet as slave\n"); diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h index cd0a6bcbe74a..0d568dcfd65a 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h @@ -65,7 +65,7 @@ struct rmnet_priv { struct rmnet_priv_stats stats; }; -struct rmnet_port *rmnet_get_port(struct net_device *real_dev); +struct rmnet_port *rmnet_get_port_rcu(struct net_device *real_dev); struct rmnet_endpoint *rmnet_get_endpoint(struct rmnet_port *port, u8 mux_id); int rmnet_add_bridge(struct net_device *rmnet_dev, struct net_device *slave_dev, diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c index 1b74bc160402..074a8b326c30 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c @@ -184,7 +184,7 @@ rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb) return RX_HANDLER_PASS; dev = skb->dev; - port = rmnet_get_port(dev); + port = rmnet_get_port_rcu(dev); switch (port->rmnet_mode) { case RMNET_EPMODE_VND: @@ -217,7 +217,7 @@ void rmnet_egress_handler(struct sk_buff *skb) skb->dev = priv->real_dev; mux_id = priv->mux_id; - port = rmnet_get_port(skb->dev); + port = rmnet_get_port_rcu(skb->dev); if (!port) goto drop;