From patchwork Thu Aug 20 09:20:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 265511 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=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 3DD96C433E1 for ; Thu, 20 Aug 2020 11:59:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EBD6214F1 for ; Thu, 20 Aug 2020 11:59:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597924754; bh=ZGfKLK7QDF6UKIB9ZK1taXhdAkb39nAqHSWRWISVJDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sfcrcK+yyASdkFFX3EGolEgu/ldIXAF7vQrAeh2J0vI87deY4DfalyhVh9QsEZlvG xHiMLdWRaNkz5BlVM/+s0ELouZTv024M97gqIwJQxmHsAtTXvQ96t/7NfVAn9g7/Qs U9Q7RwkiYw3UjFbxmtC+CPWVr0mTXh3W7JOydye4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728211AbgHTL7N (ORCPT ); Thu, 20 Aug 2020 07:59:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:48998 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730191AbgHTKAi (ORCPT ); Thu, 20 Aug 2020 06:00:38 -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 A10C9207FB; Thu, 20 Aug 2020 10:00:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597917637; bh=ZGfKLK7QDF6UKIB9ZK1taXhdAkb39nAqHSWRWISVJDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sPKxxlGeiKgz3oMq2pCZv/ndhJkdWXH2vOrvUFsTkvP93mYpLAzndPOlk5+/t3nsw s5CrAwrbuj8XdMX/X528NUP8kMi3i0is11QwfoQHRV4dkfAwFl8/vBMXAfTN2CDrfJ Gopzw76fFp2iV2/+4IlNr7Ai2LYzSoUReuwQYICo= 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 4.9 072/212] ipv4: Silence suspicious RCU usage warning Date: Thu, 20 Aug 2020 11:20:45 +0200 Message-Id: <20200820091605.997432275@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091602.251285210@linuxfoundation.org> References: <20200820091602.251285210@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 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 @@ -1719,7 +1719,7 @@ 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)