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 1B11359B71 for ; Tue, 22 Oct 2024 15:44:05 +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=1729611846; cv=none; b=fyuyZCZJ/P9ms1JcwYfL/Oh39lURICk4V+qYUJ480jYdz6CfsW6X2CmxEI4i3LRoGymTQ9fM5AdxuyctHbekyJ84XbdVSRxdiKu0zbGe3xs2WNgSWK1wjg4yrVB9lQLg4Zf2FuRlnfTNuMZk4ajglqtNzM/3vypSSgpR75uCebk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729611846; c=relaxed/simple; bh=2n0DwXyfQztO24SkX/DpDvIgRxJaMfVCH8AFQ25yZEs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Gwi1OuGFJhCzQRyVQONTAPf8+LY/bs9hYlr4c/q0JYaqxal9PquTkZOPHRFTq6uQgAxMJz3R4uZOICAaGnYFe/PKgrE/NxEc2JIsXsdv/JGMLp95rVa/q2UlP+P9mkbtTBy+1mA+brznS8vgGp6dQ3LBfvYPnV5fjSSaOUstRvw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aTtejDMl; 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="aTtejDMl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51E6BC4CEC3; Tue, 22 Oct 2024 15:44:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729611845; bh=2n0DwXyfQztO24SkX/DpDvIgRxJaMfVCH8AFQ25yZEs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=aTtejDMl9IH5GqE/2GfEy1xvYR0fWXiXTYWZXCkv3AL6Ps+H04sAuJ2e1ck8dygLB dIYBZNPGeZQuIkkPkXAxMg95V8s7GMazus3Vlxk0vMrKMUrTc7KbFdgx0yAczYnIFA LY/iTi5rY+sisA38H8sQqFt2/8LVH+JT0lXGs1hDkhu6D3+QD/1tk0rtQp7IlBeIu/ iXVAOpvQMvUGj1QEClsdEAPxwLwWvDzpaSmiVPIkOVJ5sF6Wm+ToSzsIbi2xt8iNyY ACZgkbB9+92t5tUHAN5SJ22MkpUOQYK9pRR5V4KfhduPGiGAh1lfxcDJl+8pbR9Lbc rDNCYMSPgNyqA== Message-ID: <529331cf-4791-4e6c-ab67-89d6dde66f90@kernel.org> Date: Tue, 22 Oct 2024 09:44:04 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] ipv4: ip_tunnel: Fix suspicious RCU usage warning in ip_tunnel_init_flow() Content-Language: en-US To: Ido Schimmel , netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, horms@kernel.org References: <20241022063822.462057-1-idosch@nvidia.com> From: David Ahern In-Reply-To: <20241022063822.462057-1-idosch@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/22/24 12:38 AM, Ido Schimmel wrote: > There are code paths from which the function is called without holding > the RCU read lock, resulting in a suspicious RCU usage warning [1]. > > Fix by using l3mdev_master_upper_ifindex_by_index() which will acquire > the RCU read lock before calling > l3mdev_master_upper_ifindex_by_index_rcu(). > > [1] > WARNING: suspicious RCU usage > 6.12.0-rc3-custom-gac8f72681cf2 #141 Not tainted > ----------------------------- > net/core/dev.c:876 RCU-list traversed in non-reader section!! > > other info that might help us debug this: > > rcu_scheduler_active = 2, debug_locks = 1 > 1 lock held by ip/361: > #0: ffffffff86fc7cb0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x377/0xf60 > > stack backtrace: > CPU: 3 UID: 0 PID: 361 Comm: ip Not tainted 6.12.0-rc3-custom-gac8f72681cf2 #141 > Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > Call Trace: > > dump_stack_lvl+0xba/0x110 > lockdep_rcu_suspicious.cold+0x4f/0xd6 > dev_get_by_index_rcu+0x1d3/0x210 > l3mdev_master_upper_ifindex_by_index_rcu+0x2b/0xf0 > ip_tunnel_bind_dev+0x72f/0xa00 > ip_tunnel_newlink+0x368/0x7a0 > ipgre_newlink+0x14c/0x170 > __rtnl_newlink+0x1173/0x19c0 > rtnl_newlink+0x6c/0xa0 > rtnetlink_rcv_msg+0x3cc/0xf60 > netlink_rcv_skb+0x171/0x450 > netlink_unicast+0x539/0x7f0 > netlink_sendmsg+0x8c1/0xd80 > ____sys_sendmsg+0x8f9/0xc20 > ___sys_sendmsg+0x197/0x1e0 > __sys_sendmsg+0x122/0x1f0 > do_syscall_64+0xbb/0x1d0 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Fixes: db53cd3d88dc ("net: Handle l3mdev in ip_tunnel_init_flow") > Signed-off-by: Ido Schimmel > --- > include/net/ip_tunnels.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > Reviewed-by: David Ahern