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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,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 181BCC072B1 for ; Thu, 30 May 2019 03:59:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DBC4E24F29 for ; Thu, 30 May 2019 03:59:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559188782; bh=Npxmw6nnvgD0ZjvtCKn1B+RkWhFeIgCUudF25HHwcB4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=oMPUepV0/SOvTK6WmI9hezJ5gGYJKre/z/3ssarzKAQqrAoxGpDQRuEgalBwJR+zw VwAiRp7/G/7ca60Ki5/ui50X+2vw2lvnRbygBU++/yy7JVnMvrpwBczDK4lELX7gnh 2SWz/Zjgnjmq5AfdKX5b+on9dre8QHFXQ0Jujk2A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726743AbfE3D7l (ORCPT ); Wed, 29 May 2019 23:59:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:51776 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731585AbfE3DSd (ORCPT ); Wed, 29 May 2019 23:18:33 -0400 Received: from localhost (ip67-88-213-2.z213-88-67.customer.algx.net [67.88.213.2]) (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 E96C82475F; Thu, 30 May 2019 03:18:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559186313; bh=Npxmw6nnvgD0ZjvtCKn1B+RkWhFeIgCUudF25HHwcB4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vuDYpk/LUMqDsPLFXlQ4P45lDuzfzKIQfxAbuxTTyn5e2sqNB5ufhJZWDPLXqY7ng B2ajfskZAqL/h3ZpVyYKkzzjxej/JX9aIFztxoySOdU92JpphiSXfdDtx2rylM2q6F LlVcom8lFRD1mLjMo9EAzdh0JDG6zjoHMybYGpYk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Gruenbacher Subject: [PATCH 4.14 015/193] gfs2: Fix sign extension bug in gfs2_update_stats Date: Wed, 29 May 2019 20:04:29 -0700 Message-Id: <20190530030450.062891747@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030446.953835040@linuxfoundation.org> References: <20190530030446.953835040@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andreas Gruenbacher commit 5a5ec83d6ac974b12085cd99b196795f14079037 upstream. Commit 4d207133e9c3 changed the types of the statistic values in struct gfs2_lkstats from s64 to u64. Because of that, what should be a signed value in gfs2_update_stats turned into an unsigned value. When shifted right, we end up with a large positive value instead of a small negative value, which results in an incorrect variance estimate. Fixes: 4d207133e9c3 ("gfs2: Make statistics unsigned, suitable for use with do_div()") Signed-off-by: Andreas Gruenbacher Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Greg Kroah-Hartman --- fs/gfs2/lock_dlm.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/fs/gfs2/lock_dlm.c +++ b/fs/gfs2/lock_dlm.c @@ -31,9 +31,10 @@ * @delta is the difference between the current rtt sample and the * running average srtt. We add 1/8 of that to the srtt in order to * update the current srtt estimate. The variance estimate is a bit - * more complicated. We subtract the abs value of the @delta from - * the current variance estimate and add 1/4 of that to the running - * total. + * more complicated. We subtract the current variance estimate from + * the abs value of the @delta and add 1/4 of that to the running + * total. That's equivalent to 3/4 of the current variance + * estimate plus 1/4 of the abs of @delta. * * Note that the index points at the array entry containing the smoothed * mean value, and the variance is always in the following entry @@ -49,7 +50,7 @@ static inline void gfs2_update_stats(str s64 delta = sample - s->stats[index]; s->stats[index] += (delta >> 3); index++; - s->stats[index] += ((abs(delta) - s->stats[index]) >> 2); + s->stats[index] += (s64)(abs(delta) - s->stats[index]) >> 2; } /**