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=-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 89CFAC433E0 for ; Mon, 10 Aug 2020 15:30:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5541C22D74 for ; Mon, 10 Aug 2020 15:30:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597073421; bh=MW7J+hsXgn9nQY2RcNiaq6t9NpgkfUGMv8o3WrLLBRI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MwElvZtAnaZq1Qbh/iEs5rJeGSl9PGxMJrZZa4AK4Px5At2JnBC7AGf5Wwe4dtvF6 knawawR24G24tKkdhRx+xF4ak8eZTgJh90d1UVu8RThkNBEHKmeFG1PIP9ugG7a9Hg WLh76iMWxVJxQ4xThI9ndCNK+QhkxCZRelLkH5bI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729065AbgHJPaS (ORCPT ); Mon, 10 Aug 2020 11:30:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:37064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729063AbgHJPaQ (ORCPT ); Mon, 10 Aug 2020 11:30:16 -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 B2DB620791; Mon, 10 Aug 2020 15:30:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597073416; bh=MW7J+hsXgn9nQY2RcNiaq6t9NpgkfUGMv8o3WrLLBRI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kEQe//z5f/BuDqgm4HpNEj8eAvYAGns5a610y+yPmAWptG1J+YnVSfms5u29WGuTJ jz8FqRx+7IrLE8rOfwz7OCbRHxPsjkyFGwVMVy8XKp0YHo0ISCOQaf1Q+DOKxdMcY6 c5M1eR/KecaPW114IKCsyKSP34aZ2NX9Rn3Q0Ygw= 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 4.19 32/48] ipv4: Silence suspicious RCU usage warning Date: Mon, 10 Aug 2020 17:21:54 +0200 Message-Id: <20200810151805.790694863@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200810151804.199494191@linuxfoundation.org> References: <20200810151804.199494191@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ido Schimmel [ Upstream commit 83f3522860f702748143e022f1a546547314c715 ] fib_trie_unmerge() is called with RTNL held, but not from an RCU read-side critical section. This leads to the following warning [1] when the FIB alias list in a leaf is traversed with hlist_for_each_entry_rcu(). Since the function is always called with RTNL held and since modification of the list is protected by RTNL, simply use hlist_for_each_entry() and silence the warning. [1] WARNING: suspicious RCU usage 5.8.0-rc4-custom-01520-gc1f937f3f83b #30 Not tainted ----------------------------- net/ipv4/fib_trie.c:1867 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/164: #0: ffffffff85a27850 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x49a/0xbd0 stack backtrace: CPU: 0 PID: 164 Comm: ip Not tainted 5.8.0-rc4-custom-01520-gc1f937f3f83b #30 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 fib_trie_unmerge+0x608/0xdb0 fib_unmerge+0x44/0x360 fib4_rule_configure+0xc8/0xad0 fib_nl_newrule+0x37a/0x1dd0 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+0x54/0xa0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fc80a234e97 Code: Bad RIP value. RSP: 002b:00007ffef8b66798 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc80a234e97 RDX: 0000000000000000 RSI: 00007ffef8b66800 RDI: 0000000000000003 RBP: 000000005f141b1c R08: 0000000000000001 R09: 0000000000000000 R10: 00007fc80a2a8ac0 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 00007ffef8b67008 R15: 0000556fccb10020 Fixes: 0ddcf43d5d4a ("ipv4: FIB Local/MAIN table collapse") Signed-off-by: Ido Schimmel Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/fib_trie.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -1749,7 +1749,7 @@ struct fib_table *fib_trie_unmerge(struc while ((l = leaf_walk_rcu(&tp, key)) != NULL) { struct key_vector *local_l = NULL, *local_tp; - hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) { + hlist_for_each_entry(fa, &l->leaf, fa_list) { struct fib_alias *new_fa; if (local_tb->tb_id != fa->tb_id)