From patchwork Wed Jul 6 23:39:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12908910 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 15F7AC433EF for ; Wed, 6 Jul 2022 23:42:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234819AbiGFXmB (ORCPT ); Wed, 6 Jul 2022 19:42:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234777AbiGFXlu (ORCPT ); Wed, 6 Jul 2022 19:41:50 -0400 Received: from smtp-fw-6001.amazon.com (smtp-fw-6001.amazon.com [52.95.48.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1CD262CE26; Wed, 6 Jul 2022 16:41:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1657150910; x=1688686910; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=/M11D+ZL2bejtlLvWMmLudSrsjwDj6P5JFV1eyWk4mc=; b=uvVUT/16UJD/CFq7vv1gPe7TksAY3tAXcFpoUEqDfw4inMA4dHmUv4PH IRBKMhCIscsA602kWAmEgEgEZd6MG1TzmIJOIH1KNDXp4M8a9/zqKw6nv C8vUlXYeNuY7IMizYnGTTEtze/Z6pYrYYHK26EQon1wtHYqLS2I+9G3kF Y=; Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-iad-1e-54c9d11f.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-6001.iad6.amazon.com with ESMTP; 06 Jul 2022 23:41:38 +0000 Received: from EX13MTAUWB001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan2.iad.amazon.com [10.40.163.34]) by email-inbound-relay-iad-1e-54c9d11f.us-east-1.amazon.com (Postfix) with ESMTPS id 68FFBC08C1; Wed, 6 Jul 2022 23:41:35 +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 23:41:34 +0000 Received: from 88665a182662.ant.amazon.com (10.43.160.106) 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 23:41:31 +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 , , Subject: [PATCH v2 net 04/12] sysctl: Fix data races in proc_douintvec_minmax(). Date: Wed, 6 Jul 2022 16:39:55 -0700 Message-ID: <20220706234003.66760-5-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220706234003.66760-1-kuniyu@amazon.com> References: <20220706234003.66760-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.160.106] X-ClientProxiedBy: EX13D36UWB001.ant.amazon.com (10.43.161.84) 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 A sysctl variable is accessed concurrently, and there is always a chance of data-race. So, all readers and writers need some basic protection to avoid load/store-tearing. This patch changes proc_douintvec_minmax() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_douintvec_minmax() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side. Fixes: 61d9b56a8920 ("sysctl: add unsigned int range support") Signed-off-by: Kuniyuki Iwashima --- kernel/sysctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 4d87832367f2..379721a03d41 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -923,7 +923,7 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp, (param->max && *param->max < tmp)) return -ERANGE; - *valp = tmp; + WRITE_ONCE(*valp, tmp); } return 0;