From owner-svn-src-all@freebsd.org Sun Feb 10 23:07:47 2019 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B1D0A14E07B8; Sun, 10 Feb 2019 23:07:47 +0000 (UTC) (envelope-from cem@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 5702D70AD1; Sun, 10 Feb 2019 23:07:47 +0000 (UTC) (envelope-from cem@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4BC801F3FE; Sun, 10 Feb 2019 23:07:47 +0000 (UTC) (envelope-from cem@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x1AN7leg011618; Sun, 10 Feb 2019 23:07:47 GMT (envelope-from cem@FreeBSD.org) Received: (from cem@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x1AN7lj8011617; Sun, 10 Feb 2019 23:07:47 GMT (envelope-from cem@FreeBSD.org) Message-Id: <201902102307.x1AN7lj8011617@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: cem set sender to cem@FreeBSD.org using -f From: Conrad Meyer Date: Sun, 10 Feb 2019 23:07:47 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r343985 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: cem X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 343985 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 5702D70AD1 X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-2.97 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_HAM_MEDIUM(-1.00)[-0.996,0]; NEURAL_HAM_SHORT(-0.98)[-0.976,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 10 Feb 2019 23:07:47 -0000 Author: cem Date: Sun Feb 10 23:07:46 2019 New Revision: 343985 URL: https://svnweb.freebsd.org/changeset/base/343985 Log: Prevent overflow for usertime/systime in caclru1 PR: 76972 and duplicates Reported by: Dr. Christopher Landauer , Steinar Haug Submitted by: Andrey Zonov (earlier version) MFC after: 2 weeks Modified: head/sys/kern/kern_resource.c Modified: head/sys/kern/kern_resource.c ============================================================================== --- head/sys/kern/kern_resource.c Sun Feb 10 22:33:41 2019 (r343984) +++ head/sys/kern/kern_resource.c Sun Feb 10 23:07:46 2019 (r343985) @@ -863,6 +863,15 @@ rufetchtd(struct thread *td, struct rusage *ru) calcru1(p, &td->td_rux, &ru->ru_utime, &ru->ru_stime); } +static uint64_t +mul64_by_fraction(uint64_t a, uint64_t b, uint64_t c) +{ + /* + * Compute floor(a * (b / c)) without overflowing, (b / c) <= 1.0. + */ + return ((a / c) * b + (a % c) * (b / c) + (a % c) * (b % c) / c); +} + static void calcru1(struct proc *p, struct rusage_ext *ruxp, struct timeval *up, struct timeval *sp) @@ -892,10 +901,10 @@ calcru1(struct proc *p, struct rusage_ext *ruxp, struc * The normal case, time increased. * Enforce monotonicity of bucketed numbers. */ - uu = (tu * ut) / tt; + uu = mul64_by_fraction(tu, ut, tt); if (uu < ruxp->rux_uu) uu = ruxp->rux_uu; - su = (tu * st) / tt; + su = mul64_by_fraction(tu, st, tt); if (su < ruxp->rux_su) su = ruxp->rux_su; } else if (tu + 3 > ruxp->rux_tu || 101 * tu > 100 * ruxp->rux_tu) { @@ -924,8 +933,8 @@ calcru1(struct proc *p, struct rusage_ext *ruxp, struc "to %ju usec for pid %d (%s)\n", (uintmax_t)ruxp->rux_tu, (uintmax_t)tu, p->p_pid, p->p_comm); - uu = (tu * ut) / tt; - su = (tu * st) / tt; + uu = mul64_by_fraction(tu, ut, tt); + su = mul64_by_fraction(tu, st, tt); } ruxp->rux_uu = uu;