From patchwork Mon Aug 10 15:21:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 266619 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95314C433DF for ; Mon, 10 Aug 2020 15:39:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6458E22D6F for ; Mon, 10 Aug 2020 15:39:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597073976; bh=kfezLy7BHksJ+DhKywSCaSISLD3lx0y6THaBhBWV3RE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IxzDC96Ug5TaOM31UfZvWrmRYqkUAjnVYsrmJDrnfR+HQGhbRqEREPhFZXKC4Jg9j 7gFOSn+hRXOogTl6GWEQhaNrv25L11xNeazvWOr3Ryk81LB3xxgLQez+uycm2q3M3s FJGvmsreWcweEBJaNBI2L0AEJ8/t5tG6ELRTIz44= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727799AbgHJPjf (ORCPT ); Mon, 10 Aug 2020 11:39:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:57992 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728115AbgHJPYl (ORCPT ); Mon, 10 Aug 2020 11:24:41 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7AB1220772; Mon, 10 Aug 2020 15:24:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597073080; bh=kfezLy7BHksJ+DhKywSCaSISLD3lx0y6THaBhBWV3RE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZWni3k6W+s8yH2sQWtWjWYiFz9Ua676+mGWSQSqDiglYTPBMzMNuBn6JkJcaH8+G+ FThVoF8+m4bl8q0JnUvtt/3X3cGvnsLC6/NgcfV7mjUZ3+VG4YauDGyHWCNKawrvY3 MLhUeWvrX/oN5WK27uLQaO4rCQrJpxZkfAsEdhBk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ido Schimmel , Jiri Pirko , "David S. Miller" Subject: [PATCH 5.7 59/79] vxlan: Ensure FDB dump is performed under RCU Date: Mon, 10 Aug 2020 17:21:18 +0200 Message-Id: <20200810151815.164777566@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200810151812.114485777@linuxfoundation.org> References: <20200810151812.114485777@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ido Schimmel [ Upstream commit b5141915b5aec3b29a63db869229e3741ebce258 ] The commit cited below removed the RCU read-side critical section from rtnl_fdb_dump() which means that the ndo_fdb_dump() callback is invoked without RCU protection. This results in the following warning [1] in the VXLAN driver, which relied on the callback being invoked from an RCU read-side critical section. Fix this by calling rcu_read_lock() in the VXLAN driver, as already done in the bridge driver. [1] WARNING: suspicious RCU usage 5.8.0-rc4-custom-01521-g481007553ce6 #29 Not tainted ----------------------------- drivers/net/vxlan.c:1379 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 bridge/166: #0: ffffffff85a27850 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0xea/0x1090 stack backtrace: CPU: 1 PID: 166 Comm: bridge Not tainted 5.8.0-rc4-custom-01521-g481007553ce6 #29 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x100/0x184 lockdep_rcu_suspicious+0x153/0x15d vxlan_fdb_dump+0x51e/0x6d0 rtnl_fdb_dump+0x4dc/0xad0 netlink_dump+0x540/0x1090 __netlink_dump_start+0x695/0x950 rtnetlink_rcv_msg+0x802/0xbd0 netlink_rcv_skb+0x17a/0x480 rtnetlink_rcv+0x22/0x30 netlink_unicast+0x5ae/0x890 netlink_sendmsg+0x98a/0xf40 __sys_sendto+0x279/0x3b0 __x64_sys_sendto+0xe6/0x1a0 do_syscall_64+0x54/0xa0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fe14fa2ade0 Code: Bad RIP value. RSP: 002b:00007fff75bb5b88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00005614b1ba0020 RCX: 00007fe14fa2ade0 RDX: 000000000000011c RSI: 00007fff75bb5b90 RDI: 0000000000000003 RBP: 00007fff75bb5b90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00005614b1b89160 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Fixes: 5e6d24358799 ("bridge: netlink dump interface at par with brctl") Signed-off-by: Ido Schimmel Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/vxlan.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -1225,6 +1225,7 @@ static int vxlan_fdb_dump(struct sk_buff for (h = 0; h < FDB_HASH_SIZE; ++h) { struct vxlan_fdb *f; + rcu_read_lock(); hlist_for_each_entry_rcu(f, &vxlan->fdb_head[h], hlist) { struct vxlan_rdst *rd; @@ -1237,12 +1238,15 @@ static int vxlan_fdb_dump(struct sk_buff cb->nlh->nlmsg_seq, RTM_NEWNEIGH, NLM_F_MULTI, rd); - if (err < 0) + if (err < 0) { + rcu_read_unlock(); goto out; + } skip: *idx += 1; } } + rcu_read_unlock(); } out: return err;