From patchwork Wed Mar 25 15:55:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qian Cai X-Patchwork-Id: 1261521 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=lca.pw header.i=@lca.pw header.a=rsa-sha256 header.s=google header.b=hUPBtEbE; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48nXlm1Yc5z9sQx for ; Thu, 26 Mar 2020 02:56:04 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727956AbgCYP4D (ORCPT ); Wed, 25 Mar 2020 11:56:03 -0400 Received: from mail-qt1-f195.google.com ([209.85.160.195]:33838 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727912AbgCYP4D (ORCPT ); Wed, 25 Mar 2020 11:56:03 -0400 Received: by mail-qt1-f195.google.com with SMTP id 10so2595568qtp.1 for ; Wed, 25 Mar 2020 08:56:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=5LjboPnDfMYr+D+3numlwyKRNovhORGQjxZDfSq6m9Y=; b=hUPBtEbERszA+YII5Yxm3jnhf4gWvrQeMIUx7nRUKWsaVY/hTEbkcVwZ824Se5rjur x16y9PSdBsh167UfAZB5rT8bdfE8B41JnUCsPalmpfBxfrdDF/j6w9juDr9y/qiY8f1h pNQfeGBclLRBzT/fGnw6z3HBUlqE3UAo1M36/bqz9zfViGSlGkvioTbJiS2pCU7VlNop OQdFs/PIbIFnGIxs+zlMC8scqnUkRuWE0TWt3fVrW/7JpC5dxhnn5niw6m4tH5ntSp8s qpps1r0bF2/oiW3GuFKkRAgQUlhbibiMzAZHDiUoxY2kjLYpzPOqOSgyvIRDqfhyupYy 4Vew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=5LjboPnDfMYr+D+3numlwyKRNovhORGQjxZDfSq6m9Y=; b=UHy0f7o5o4PutCCEi37fiA1KGz9cBLHCRuNzny0AQypUFrh1MaroIIPALlGc2moIkF Xslnq9bGiFvNc2TkaRKuJJZ+dmZNs0CqFZRiTkPVOHaTTTBwta3nALnhwC/rztXsw3Mu MnoZmtzXJD1VOOz8rp/DH+lHlLI9dEB9Lyhwj55M6UCxrc51kWDWEf878xB4ZqfQRMSj dyepueXePZYljaFuSQFf+CvXQYUjd3t96WVtCR8IP6yAcnQ6HUtRNxkNjHaV+yih7C+0 COTbdn0xiyoGyQxGVFwLPmmzhYGFMNr/i7/+7v+nsXOogjpoZ1VpuN/uXeEZVNEPLdUL /3pA== X-Gm-Message-State: ANhLgQ2trx0rM2gdytzVMmX3C5l8QIGZRHJZVeUqR2Dm/NZsUS+T8XFh Nr7Y/scKEMelpAoU+o2YTqRZbAIhFImngA== X-Google-Smtp-Source: ADFU+vsnGtXHOB3Q1SbOrengVFBDEEpEz+h2e/kMJ6fU6G+kU2YhLUoG6gF8c+vYKIE7feOWLDUscQ== X-Received: by 2002:ac8:346f:: with SMTP id v44mr3526427qtb.205.1585151761950; Wed, 25 Mar 2020 08:56:01 -0700 (PDT) Received: from ovpn-66-69.rdu2.redhat.com (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id t23sm17931750qtj.63.2020.03.25.08.55.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Mar 2020 08:55:47 -0700 (PDT) From: Qian Cai To: davem@davemloft.net Cc: kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH] ipv4: fix a RCU-list lock in fib_triestat_seq_show Date: Wed, 25 Mar 2020 11:55:32 -0400 Message-Id: <20200325155532.7238-1-cai@lca.pw> X-Mailer: git-send-email 2.21.0 (Apple Git-122.2) MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org fib_triestat_seq_show() calls hlist_for_each_entry_rcu(tb, head, tb_hlist) without rcu_read_lock() will trigger a warning, net/ipv4/fib_trie.c:2579 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 proc01/115277: #0: c0000014507acf00 (&p->lock){+.+.}-{3:3}, at: seq_read+0x58/0x670 Call Trace: dump_stack+0xf4/0x164 (unreliable) lockdep_rcu_suspicious+0x140/0x164 fib_triestat_seq_show+0x750/0x880 seq_read+0x1a0/0x670 proc_reg_read+0x10c/0x1b0 __vfs_read+0x3c/0x70 vfs_read+0xac/0x170 ksys_read+0x7c/0x140 system_call+0x5c/0x68 Signed-off-by: Qian Cai --- net/ipv4/fib_trie.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index ff0c24371e33..73fa37476f03 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -2577,6 +2577,7 @@ static int fib_triestat_seq_show(struct seq_file *seq, void *v) " %zd bytes, size of tnode: %zd bytes.\n", LEAF_SIZE, TNODE_SIZE(0)); + rcu_read_lock(); for (h = 0; h < FIB_TABLE_HASHSZ; h++) { struct hlist_head *head = &net->ipv4.fib_table_hash[h]; struct fib_table *tb; @@ -2597,6 +2598,7 @@ static int fib_triestat_seq_show(struct seq_file *seq, void *v) #endif } } + rcu_read_unlock(); return 0; }