From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 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=unavailable 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 88D11C433E2 for ; Fri, 11 Sep 2020 14:30:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A6DC22286 for ; Fri, 11 Sep 2020 14:30:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599834619; bh=9FMYo2bufVujsHw85HNr708jaQ3F376AuTAIpj9bjuQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZRsvOekuiXun9vhxiWBRPgHk7gaR8CVw8dPSAHhfWo0zMnzP8XfMV9h8+J0n6UUZJ FxiYhBZlp7tS8PRhWLRRe6wn1A7ucLYINmxicHoVXaP6XJ/M4D0zAqs6CWY8ccOwuz w4GWzVBjOARI6k5KHk9iCMAtNeG8aOtkXguEw7j0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726253AbgIKOaJ (ORCPT ); Fri, 11 Sep 2020 10:30:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:56036 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726101AbgIKNMA (ORCPT ); Fri, 11 Sep 2020 09:12:00 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 B992D2245F; Fri, 11 Sep 2020 13:00:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599829233; bh=9FMYo2bufVujsHw85HNr708jaQ3F376AuTAIpj9bjuQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WNWME/k1O/d7VwmZGjF8r4hGgwpjLbu41LG+SFXxc5JnKEBJr/UPOjx7v2knLvZv7 5LLL09ilmh5MaHgEdOfJniDWbjCTp7TtqCKv2/DDFI3XWIP4DGpnjg01ZeGM3YKM7E +w2qi1kLWm1PkdjBPnBBBUpsKwK2U0aVKYKNF1ZE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ido Schimmel , David Ahern , "David S. Miller" Subject: [PATCH 5.4 1/8] ipv4: Silence suspicious RCU usage warning Date: Fri, 11 Sep 2020 14:54:39 +0200 Message-Id: <20200911125420.653876365@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200911125420.580564179@linuxfoundation.org> References: <20200911125420.580564179@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ido Schimmel [ Upstream commit 7f6f32bb7d3355cd78ebf1dece9a6ea7a0ca8158 ] fib_info_notify_update() is always called with RTNL held, but not from an RCU read-side critical section. This leads to the following warning [1] when the FIB table list is traversed with hlist_for_each_entry_rcu(), but without a proper lockdep expression. Since modification of the list is protected by RTNL, silence the warning by adding a lockdep expression which verifies RTNL is held. [1] ============================= WARNING: suspicious RCU usage 5.9.0-rc1-custom-14233-g2f26e122d62f #129 Not tainted ----------------------------- net/ipv4/fib_trie.c:2124 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/834: #0: ffffffff85a3b6b0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x49a/0xbd0 stack backtrace: CPU: 0 PID: 834 Comm: ip Not tainted 5.9.0-rc1-custom-14233-g2f26e122d62f #129 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+0x143/0x14d fib_info_notify_update+0x8d1/0xa60 __nexthop_replace_notify+0xd2/0x290 rtm_new_nexthop+0x35e2/0x5946 rtnetlink_rcv_msg+0x4f7/0xbd0 netlink_rcv_skb+0x17a/0x480 rtnetlink_rcv+0x22/0x30 netlink_unicast+0x5ae/0x890 netlink_sendmsg+0x98a/0xf40 ____sys_sendmsg+0x879/0xa00 ___sys_sendmsg+0x122/0x190 __sys_sendmsg+0x103/0x1d0 __x64_sys_sendmsg+0x7d/0xb0 do_syscall_64+0x32/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fde28c3be57 Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 RSP: 002b:00007ffc09330028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fde28c3be57 RDX: 0000000000000000 RSI: 00007ffc09330090 RDI: 0000000000000003 RBP: 000000005f45f911 R08: 0000000000000001 R09: 00007ffc0933012c R10: 0000000000000076 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc09330290 R14: 00007ffc09330eee R15: 00005610e48ed020 Fixes: 1bff1a0c9bbd ("ipv4: Add function to send route updates") Signed-off-by: Ido Schimmel Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/fib_trie.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -2010,7 +2010,8 @@ void fib_info_notify_update(struct net * struct hlist_head *head = &net->ipv4.fib_table_hash[h]; struct fib_table *tb; - hlist_for_each_entry_rcu(tb, head, tb_hlist) + hlist_for_each_entry_rcu(tb, head, tb_hlist, + lockdep_rtnl_is_held()) __fib_info_notify_update(net, tb, info); } }