From patchwork Wed Apr 22 09:57:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 227067 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 CB745C5518A for ; Wed, 22 Apr 2020 10:54:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1CE52076E for ; Wed, 22 Apr 2020 10:54:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587552878; bh=nCa1oM8XT517eLWFGFsYd+m5KajbIUI2sv+i1okp1tE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=va9sw4Lt607ShX7uIRoM4YuD5JQaegy7YvOISO5YlZ5jXMSK0W/ayusmpXsB2Ic2y Q79Br1o/nzt2Iac97DZn6eJspAt9J4nQDow/0MT08zU5JMRx193Z00H/hYYOptc5WV 8VMwPeq65ffhRVrWz4fI1FSrK+d2CzIWZ2XipQU8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728575AbgDVKHt (ORCPT ); Wed, 22 Apr 2020 06:07:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:60602 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728572AbgDVKHp (ORCPT ); Wed, 22 Apr 2020 06:07:45 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 60DC320774; Wed, 22 Apr 2020 10:07:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587550064; bh=nCa1oM8XT517eLWFGFsYd+m5KajbIUI2sv+i1okp1tE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FN7cwchqOcT23rLt3Qbdr7ARjz7U30/uBI9OuGKBki6e2B8cTiqoTxXrqVwnKNEtt d+Ru693W9e+YXmOQRvqr8UhxWUUkmmHxu0Ht8Gp5GripqEkr1AvHZ5/yH1bfZkRRiP R4QZSuBxYJRpG0Eu7dNwtjhKvrTyjx7604tldmOI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Will Deacon , "Paul E. McKenney" , Davidlohr Bueso , Josh Triplett , Peter Zijlstra Subject: [PATCH 4.9 120/125] locktorture: Print ratio of acquisitions, not failures Date: Wed, 22 Apr 2020 11:57:17 +0200 Message-Id: <20200422095051.906433563@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200422095032.909124119@linuxfoundation.org> References: <20200422095032.909124119@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paul E. McKenney commit 80c503e0e68fbe271680ab48f0fe29bc034b01b7 upstream. The __torture_print_stats() function in locktorture.c carefully initializes local variable "min" to statp[0].n_lock_acquired, but then compares it to statp[i].n_lock_fail. Given that the .n_lock_fail field should normally be zero, and given the initialization, it seems reasonable to display the maximum and minimum number acquisitions instead of miscomputing the maximum and minimum number of failures. This commit therefore switches from failures to acquisitions. And this turns out to be not only a day-zero bug, but entirely my own fault. I hate it when that happens! Fixes: 0af3fe1efa53 ("locktorture: Add a lock-torture kernel module") Reported-by: Will Deacon Signed-off-by: Paul E. McKenney Acked-by: Will Deacon Cc: Davidlohr Bueso Cc: Josh Triplett Cc: Peter Zijlstra Signed-off-by: Greg Kroah-Hartman --- kernel/locking/locktorture.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -649,10 +649,10 @@ static void __torture_print_stats(char * if (statp[i].n_lock_fail) fail = true; sum += statp[i].n_lock_acquired; - if (max < statp[i].n_lock_fail) - max = statp[i].n_lock_fail; - if (min > statp[i].n_lock_fail) - min = statp[i].n_lock_fail; + if (max < statp[i].n_lock_acquired) + max = statp[i].n_lock_acquired; + if (min > statp[i].n_lock_acquired) + min = statp[i].n_lock_acquired; } page += sprintf(page, "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",