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,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 A3420C28CC0 for ; Thu, 30 May 2019 04:15:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 798C92522E for ; Thu, 30 May 2019 04:15:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559189704; bh=Npxmw6nnvgD0ZjvtCKn1B+RkWhFeIgCUudF25HHwcB4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RJJOrRAtublArDtrP2Sg6Va1nWZlOI0VI1crOzcxd9+PLhQTnr+PCfeZ/Ui603BOn 5dbjZnqP+idyfQQoVBNQR7lYhDWuDiNfpE1ve+X4emF9RFvhpbjnyZUl5O1IULZmX9 nSverzx9uVoZwSu/RReHzP+Sz0W0akF+L7eUlpbg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726910AbfE3EPD (ORCPT ); Thu, 30 May 2019 00:15:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:41234 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728628AbfE3DQF (ORCPT ); Wed, 29 May 2019 23:16:05 -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 EB89923D83; Thu, 30 May 2019 03:16:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559186165; bh=Npxmw6nnvgD0ZjvtCKn1B+RkWhFeIgCUudF25HHwcB4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZwNGn9KmjlB+H4NtfHGoV4IB4DRBck9PytKnowuKSlLOGCiRgIh2TYKSvNAOVT5bs UCOxmyQhPWd0kU/z1QGs6wvqTENid0ASV8aEbWeZyOQqf9vxTANbqz9WJvy3H8dFfs WqarAjnlHNAmS73qXG6c3Apuns30DbWxUcNuHj4Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Gruenbacher Subject: [PATCH 4.19 016/276] gfs2: Fix sign extension bug in gfs2_update_stats Date: Wed, 29 May 2019 20:02:54 -0700 Message-Id: <20190530030524.947342987@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030523.133519668@linuxfoundation.org> References: <20190530030523.133519668@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; } /**