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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 4644FC433B4 for ; Thu, 13 May 2021 12:57:46 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8A32661421 for ; Thu, 13 May 2021 12:57:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A32661421 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55008 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lhAuO-0002Te-FM for qemu-devel@archiver.kernel.org; Thu, 13 May 2021 08:57:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38050) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lhAse-0000Vq-Uw for qemu-devel@nongnu.org; Thu, 13 May 2021 08:55:57 -0400 Received: from indium.canonical.com ([91.189.90.7]:50306) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lhAsa-0004TH-0g for qemu-devel@nongnu.org; Thu, 13 May 2021 08:55:55 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.93 #5 (Debian)) id 1lhAsV-0003yT-C1 for ; Thu, 13 May 2021 12:55:47 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id B25CC2E8198 for ; Thu, 13 May 2021 12:55:44 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Thu, 13 May 2021 12:49:42 -0000 From: Richard Henderson <1898011@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=Confirmed; importance=Undecided; assignee=None; X-Launchpad-Bug-Tags: linux-user mmap tcg X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: ksserebr rth th-huth ubuntu-weilnetz X-Launchpad-Bug-Reporter: Kostya Serebryany (ksserebr) X-Launchpad-Bug-Modifier: Richard Henderson (rth) References: <160153380394.6201.10648910301442382269.malonedeb@soybean.canonical.com> Message-Id: <162091018252.1097.5933051084788333980.malone@wampee.canonical.com> Subject: [Bug 1898011] Re: mmap MAP_NORESERVE of 2^42 bytes consumes 16Gb of actual RAM X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="6b3403d85f09252210977b936e821c0b00dbe016"; Instance="production" X-Launchpad-Hash: 926c3070090d04af2db98ebcf3068d672372a677 Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-Spam_score_int: -65 X-Spam_score: -6.6 X-Spam_bar: ------ X-Spam_report: (-6.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.248, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1898011 <1898011@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Still an issue, yes. ** Changed in: qemu Status: Incomplete =3D> Confirmed -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1898011 Title: mmap MAP_NORESERVE of 2^42 bytes consumes 16Gb of actual RAM Status in QEMU: Confirmed Bug description: Run this program: #include #include int main() { for (int i =3D 30; i <=3D 44; i++) { fprintf(stderr, "trying 2**%d\n", i); mmap((void*)0x600000000000,1ULL << i, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_NORESERVE= ,-1,0); } } (tried qemu-x86_64 and qemu-aarch64, 4.2.1 and trunk/5.1.50) On each iteration qemu will consume 2x more physical RAM, = e.g. when mapping 2^42 it will have RSS of 16Gb. On normal linux it works w/o consuming much RAM, due to MAP_NORESERVE. Also: qemu -strace prints 0 instead of the correct size starting from siz= e=3D2^32 and prints -2147483648 for size=3D2^31. = mmap(0x0000600000000000,1073741824,PROT_NONE,MAP_PRIVATE|MAP_ANONYMOUS|MA= P_FIXED|MAP_NORESERVE,-1,0) =3D 0x0000600000000000 mmap(0x0000600000000000,-2147483648,PROT_NONE,MAP_PRIVATE|MAP_ANONYMOUS|M= AP_FIXED|MAP_NORESERVE,-1,0) =3D 0x0000600000000000 mmap(0x0000600000000000,0,PROT_NONE,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|M= AP_NORESERVE,-1,0) =3D 0x0000600000000000 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1898011/+subscriptions