From patchwork Wed Jul 6 05:21:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12907340 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF8CDC43334 for ; Wed, 6 Jul 2022 05:25:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231836AbiGFFZy (ORCPT ); Wed, 6 Jul 2022 01:25:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231768AbiGFFZn (ORCPT ); Wed, 6 Jul 2022 01:25:43 -0400 Received: from smtp-fw-33001.amazon.com (smtp-fw-33001.amazon.com [207.171.190.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F94B21832; Tue, 5 Jul 2022 22:25:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1657085143; x=1688621143; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=aSdAx0KuWXnaOkgg5DfAI7gMMzKgwpL+M2P/sHv7FF0=; b=gcEciW5vV//+qqFkrrSSwJjEo2LM+czRIEMAuiMLAd8ldLUt/amVLSuZ q3AR+9qpYlXDGFkNokX8ubo1mTOLenrYPXkq34a5A3tSEw0Z/P92XNuiX Ly2z3pffMXwpttOfveuEQ+1Lw6+HUJU20PdUiRUgFokwFnGT8z5v4U4ng 4=; X-IronPort-AV: E=Sophos;i="5.92,249,1650931200"; d="scan'208";a="207627662" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-pdx-2c-b09ea7fa.us-west-2.amazon.com) ([10.43.8.2]) by smtp-border-fw-33001.sea14.amazon.com with ESMTP; 06 Jul 2022 05:25:41 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2c-b09ea7fa.us-west-2.amazon.com (Postfix) with ESMTPS id 8A9C143019; Wed, 6 Jul 2022 05:25:39 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.207) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Wed, 6 Jul 2022 05:25:38 +0000 Received: from 88665a182662.ant.amazon.com (10.43.162.55) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.9; Wed, 6 Jul 2022 05:25:36 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Luis Chamberlain , Kees Cook , Iurii Zaikin CC: Kuniyuki Iwashima , Kuniyuki Iwashima , , , David Ahern Subject: [PATCH v1 net 16/16] ipv4: Fix a data-race around sysctl_fib_sync_mem. Date: Tue, 5 Jul 2022 22:21:30 -0700 Message-ID: <20220706052130.16368-17-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220706052130.16368-1-kuniyu@amazon.com> References: <20220706052130.16368-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.162.55] X-ClientProxiedBy: EX13D18UWA004.ant.amazon.com (10.43.160.45) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org While reading sysctl_fib_sync_mem, it can be changed concurrently. So, we need to add READ_ONCE(). Then we can set proc_douintvec_minmax_lockless() as the handler to mark it safe. Fixes: 9ab948a91b2c ("ipv4: Allow amount of dirty memory from fib resizing to be controllable") Signed-off-by: Kuniyuki Iwashima --- CC: David Ahern --- net/ipv4/fib_trie.c | 2 +- net/ipv4/sysctl_net_ipv4.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index 2734c3af7e24..46e8a5125853 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -498,7 +498,7 @@ static void tnode_free(struct key_vector *tn) tn = container_of(head, struct tnode, rcu)->kv; } - if (tnode_free_size >= sysctl_fib_sync_mem) { + if (tnode_free_size >= READ_ONCE(sysctl_fib_sync_mem)) { tnode_free_size = 0; synchronize_rcu(); } diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 3b1d18be0857..7ea681df37c4 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -578,7 +578,7 @@ static struct ctl_table ipv4_table[] = { .data = &sysctl_fib_sync_mem, .maxlen = sizeof(sysctl_fib_sync_mem), .mode = 0644, - .proc_handler = proc_douintvec_minmax, + .proc_handler = proc_douintvec_minmax_lockless, .extra1 = &sysctl_fib_sync_mem_min, .extra2 = &sysctl_fib_sync_mem_max, },