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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A95CECAAD5 for ; Fri, 2 Sep 2022 12:40:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237215AbiIBMkp (ORCPT ); Fri, 2 Sep 2022 08:40:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237177AbiIBMim (ORCPT ); Fri, 2 Sep 2022 08:38:42 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A35F32EE2; Fri, 2 Sep 2022 05:30:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id ED79862192; Fri, 2 Sep 2022 12:29:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA119C433C1; Fri, 2 Sep 2022 12:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1662121770; bh=FufMUVUaQh+PDh29tlw9bNgetLwgT2UPVsGlg+Vo9Jk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qK8r1vH/U8TlQCH0Ar9MeVidJCO/LVGAkqh1n+wBg1Cz1JOwhqNv0htF9cb5EBPG7 DjJYFEOmXfmjBUTbLiXR73K6hKiBwS13RLR+/ZrktTnMl9JesbNcvznFs7E3Tag0gu 6+caHst0t3DEVuTS5pSnzO9lJE4VmdohPi6Je4uw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 28/77] ratelimit: Fix data-races in ___ratelimit(). Date: Fri, 2 Sep 2022 14:18:37 +0200 Message-Id: <20220902121404.582894486@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220902121403.569927325@linuxfoundation.org> References: <20220902121403.569927325@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuniyuki Iwashima [ Upstream commit 6bae8ceb90ba76cdba39496db936164fa672b9be ] While reading rs->interval and rs->burst, they can be changed concurrently via sysctl (e.g. net_ratelimit_state). Thus, we need to add READ_ONCE() to their readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- lib/ratelimit.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/lib/ratelimit.c b/lib/ratelimit.c index e01a93f46f833..ce945c17980b9 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -26,10 +26,16 @@ */ int ___ratelimit(struct ratelimit_state *rs, const char *func) { + /* Paired with WRITE_ONCE() in .proc_handler(). + * Changing two values seperately could be inconsistent + * and some message could be lost. (See: net_ratelimit_state). + */ + int interval = READ_ONCE(rs->interval); + int burst = READ_ONCE(rs->burst); unsigned long flags; int ret; - if (!rs->interval) + if (!interval) return 1; /* @@ -44,7 +50,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func) if (!rs->begin) rs->begin = jiffies; - if (time_is_before_jiffies(rs->begin + rs->interval)) { + if (time_is_before_jiffies(rs->begin + interval)) { if (rs->missed) { if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) { printk_deferred(KERN_WARNING @@ -56,7 +62,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func) rs->begin = jiffies; rs->printed = 0; } - if (rs->burst && rs->burst > rs->printed) { + if (burst && burst > rs->printed) { rs->printed++; ret = 1; } else { -- 2.35.1