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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 8DF79C33CB1 for ; Thu, 16 Jan 2020 05:53:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5605420730 for ; Thu, 16 Jan 2020 05:53:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="FqKdsNN0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726982AbgAPFxy (ORCPT ); Thu, 16 Jan 2020 00:53:54 -0500 Received: from ozlabs.org ([203.11.71.1]:41861 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726082AbgAPFxx (ORCPT ); Thu, 16 Jan 2020 00:53:53 -0500 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 47ytfm1x2Mz9sPW; Thu, 16 Jan 2020 16:53:52 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1579154032; bh=9RJsA4ixbU88RCAM8/QGkNN4hFo2PgW5OQD3mizTqI4=; h=From:To:Subject:In-Reply-To:References:Date:From; b=FqKdsNN0+BMLA/sv1/RKIUVNjSC86xzmMHFRbQrb//m3wbAbN4rnKXI9uln9OlG6o 5TlVgSy7N/4wJS42CWV1b2DqgfuWNNOAg9D2IDvHcioJiIYuaPbZHGMmTC+DYbj/Np ZX+/S7m/WmXN6ka4CEjNIYF0dVvZSEv5yMp2ooTpKtAqGPuvrTrjX6R97FYnJC/7d8 VHmD+JvS8o4D3g53Yb43H+3lA9R9U3fs+1+LVBrXTSiwkybYxVlDSinm6F7k5dVk+K JhXymh3j23dlNfXiEgcOfZQQnzvRDrXm8n9KZP5rPlvnfTz9ts+pKinLnyHlt5MbhP yj73JrISh1PRA== From: Michael Ellerman To: Michael Bringmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Gustavo Walbon , Paul Mackerras Subject: Re: [PATCH v2] Fix display of Maximum Memory In-Reply-To: <5577aef8-1d5a-ca95-ff0a-9c7b5977e5bf@linux.ibm.com> References: <5577aef8-1d5a-ca95-ff0a-9c7b5977e5bf@linux.ibm.com> Date: Thu, 16 Jan 2020 15:53:57 +1000 Message-ID: <8736cg9cay.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Michael Bringmann writes: > Correct overflow problem in calculation+display of Maximum Memory > value to syscfg where 32bits is insufficient. > > Signed-off-by: Michael Bringmann > --- > arch/powerpc/platforms/pseries/lparcfg.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c > index e33e8bc..f00411c 100644 > --- a/arch/powerpc/platforms/pseries/lparcfg.c > +++ b/arch/powerpc/platforms/pseries/lparcfg.c > @@ -433,12 +433,12 @@ static void parse_em_data(struct seq_file *m) > > static void maxmem_data(struct seq_file *m) > { > - unsigned long maxmem = 0; > + u64 maxmem = 0; This is 64-bit only code, so u64 == unsigned long. > - maxmem += drmem_info->n_lmbs * drmem_info->lmb_size; > - maxmem += hugetlb_total_pages() * PAGE_SIZE; > + maxmem += (u64)drmem_info->n_lmbs * drmem_info->lmb_size; The only problem AFAICS is n_lmbs is int and lmb_size is u32, so this multiplication will overflow. > + maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE; hugetlb_total_pages() already returns unsigned long. > - seq_printf(m, "MaxMem=%ld\n", maxmem); > + seq_printf(m, "MaxMem=%llu\n", maxmem); > } This should be sufficient? diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c index e33e8bc4b69b..38c306551f76 100644 --- a/arch/powerpc/platforms/pseries/lparcfg.c +++ b/arch/powerpc/platforms/pseries/lparcfg.c @@ -435,10 +435,10 @@ static void maxmem_data(struct seq_file *m) { unsigned long maxmem = 0; - maxmem += drmem_info->n_lmbs * drmem_info->lmb_size; + maxmem += (unsigned long)drmem_info->n_lmbs * drmem_info->lmb_size; maxmem += hugetlb_total_pages() * PAGE_SIZE; - seq_printf(m, "MaxMem=%ld\n", maxmem); + seq_printf(m, "MaxMem=%lu\n", maxmem); } static int pseries_lparcfg_data(struct seq_file *m, void *v) cheers