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=-0.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 48E9CC3A59F for ; Sat, 17 Aug 2019 16:59:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 05CBC2086C for ; Sat, 17 Aug 2019 16:59:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="IpKtW8Cq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 05CBC2086C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8E9236B0008; Sat, 17 Aug 2019 12:59:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 899AE6B000A; Sat, 17 Aug 2019 12:59:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 787986B000C; Sat, 17 Aug 2019 12:59:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0187.hostedemail.com [216.40.44.187]) by kanga.kvack.org (Postfix) with ESMTP id 508576B0008 for ; Sat, 17 Aug 2019 12:59:42 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 04A72180AD808 for ; Sat, 17 Aug 2019 16:59:42 +0000 (UTC) X-FDA: 75832531404.15.trick50_1a493a4670c42 X-HE-Tag: trick50_1a493a4670c42 X-Filterd-Recvd-Size: 7874 Received: from mail-ot1-f65.google.com (mail-ot1-f65.google.com [209.85.210.65]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Sat, 17 Aug 2019 16:59:40 +0000 (UTC) Received: by mail-ot1-f65.google.com with SMTP id j7so12402246ota.9 for ; Sat, 17 Aug 2019 09:59:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=4ctyW3Vi5Ibh5x2BY4buy9E2tmdYqlztCCfXF658lFw=; b=IpKtW8Cqml+i67WZioOBoS6hJ3Dk8T2l5C48IQHH7rT1sBA07Wda3g+B+J25rzmOed 9Qx2i000i+5Sq8rRYp2vbAoHZE02XNiTKcz/Au13aqzY9/pa7rFnoBfLd7B9nuB26GLq Y+BS4/6zRbLUvO1tOztSOjj4MBm4CQPn594UOZNJLi7bFtGBP1rj9+VwthDzYY8VVyOR UjPwA88/cVR/IQrgHEBKjDnQnFfVVKXL+DJl9I8Xuyb3TQxcwwobRlwgCjpm8tFraLxG 77Qi/VbdlEFve00vn0i/pN1lTppPcFegYQlKHrgYu35UQxOCShgs1a8NfxLtFqTSool1 L+8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=4ctyW3Vi5Ibh5x2BY4buy9E2tmdYqlztCCfXF658lFw=; b=Jp4Wp3m4l3p44+rf1xl1ZtCYVWpXYjE9t+n4XzuWVLSOFiHj+uC8wkLIM2dYZDXeOM +7DlqFueGP7Cz5siLY1vM15UItUqVMrgtCH1UpCWmNnhpbO1F9ry1CcbEPiCZ+VV2dDC 8Km6UdROb747/k4qUDPGeULkLWZ12OcHN0rOVEHdFKY19npPx65PWb3VWQuBqNlthnTJ AFrr7YYuM7JUeHIrai6baKqXFO3MtWEsQGy//mm/noesxqhnuHAaeeTBJ6X7Q+HPD8ue 1q3CNE+FJngZaVdsSCsk81pPPSdHQhPyjIZ4XvzjrsyfhJffHYFrGdalJfnj7DWjjTxU fPgg== X-Gm-Message-State: APjAAAUv+7xAjj4hOePBMunxdiKJuw/Q6jwI16dpI+9ZZNUAIkguvCzb a8p5PQ4/eSRRJioInH8QNWi31rSG3W4Hsr9UiAkWLnSv X-Google-Smtp-Source: APXvYqwHO8+aAVXPABURvgARXdHStxxHwkXAid2VAmlQqyuHa2oaAaLpAIKTgUvAj3/gNFVxCv21xdrPhnmQrGwBvxA= X-Received: by 2002:a05:6830:1e05:: with SMTP id s5mr11126021otr.247.1566061179762; Sat, 17 Aug 2019 09:59:39 -0700 (PDT) MIME-Version: 1.0 References: <1565991345.8572.28.camel@lca.pw> <0FB85A78-C2EE-4135-9E0F-D5623CE6EA47@lca.pw> In-Reply-To: From: Dan Williams Date: Sat, 17 Aug 2019 09:59:27 -0700 Message-ID: Subject: Re: devm_memremap_pages() triggers a kasan_add_zero_shadow() warning To: Qian Cai Cc: Linux MM , linux-nvdimm , Linux Kernel Mailing List , Andrey Ryabinin , kasan-dev@googlegroups.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Aug 17, 2019 at 4:13 AM Qian Cai wrote: > > > > > On Aug 16, 2019, at 11:57 PM, Dan Williams w= rote: > > > > On Fri, Aug 16, 2019 at 8:34 PM Qian Cai wrote: > >> > >> > >> > >>> On Aug 16, 2019, at 5:48 PM, Dan Williams = wrote: > >>> > >>> On Fri, Aug 16, 2019 at 2:36 PM Qian Cai wrote: > >>>> > >>>> Every so often recently, booting Intel CPU server on linux-next trig= gers this > >>>> warning. Trying to figure out if the commit 7cc7867fb061 > >>>> ("mm/devm_memremap_pages: enable sub-section remap") is the culprit = here. > >>>> > >>>> # ./scripts/faddr2line vmlinux devm_memremap_pages+0x894/0xc70 > >>>> devm_memremap_pages+0x894/0xc70: > >>>> devm_memremap_pages at mm/memremap.c:307 > >>> > >>> Previously the forced section alignment in devm_memremap_pages() woul= d > >>> cause the implementation to never violate the KASAN_SHADOW_SCALE_SIZE > >>> (12K on x86) constraint. > >>> > >>> Can you provide a dump of /proc/iomem? I'm curious what resource is > >>> triggering such a small alignment granularity. > >> > >> This is with memmap=3D4G!4G , > >> > >> # cat /proc/iomem > > [..] > >> 100000000-155dfffff : Persistent Memory (legacy) > >> 100000000-155dfffff : namespace0.0 > >> 155e00000-15982bfff : System RAM > >> 155e00000-156a00fa0 : Kernel code > >> 156a00fa1-15765d67f : Kernel data > >> 157837000-1597fffff : Kernel bss > >> 15982c000-1ffffffff : Persistent Memory (legacy) > >> 200000000-87fffffff : System RAM > > > > Ok, looks like 4G is bad choice to land the pmem emulation on this > > system because it collides with where the kernel is deployed and gets > > broken into tiny pieces that violate kasan's. This is a known problem > > with memmap=3D. You need to pick an memory range that does not collide > > with anything else. See: > > > > https://nvdimm.wiki.kernel.org/how_to_choose_the_correct_memmap_kern= el_parameter_for_pmem_on_your_system > > > > ...for more info. > > Well, it seems I did exactly follow the information in that link, > > [ 0.000000] BIOS-provided physical RAM map: > [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x0000000000093fff] usa= ble > [ 0.000000] BIOS-e820: [mem 0x0000000000094000-0x000000000009ffff] res= erved > [ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] res= erved > [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000005a7a0fff] usa= ble > [ 0.000000] BIOS-e820: [mem 0x000000005a7a1000-0x000000005b5e0fff] res= erved > [ 0.000000] BIOS-e820: [mem 0x000000005b5e1000-0x00000000790fefff] usa= ble > [ 0.000000] BIOS-e820: [mem 0x00000000790ff000-0x00000000791fefff] res= erved > [ 0.000000] BIOS-e820: [mem 0x00000000791ff000-0x000000007b5fefff] ACP= I NVS > [ 0.000000] BIOS-e820: [mem 0x000000007b5ff000-0x000000007b7fefff] ACP= I data > [ 0.000000] BIOS-e820: [mem 0x000000007b7ff000-0x000000007b7fffff] usa= ble > [ 0.000000] BIOS-e820: [mem 0x000000007b800000-0x000000008fffffff] res= erved > [ 0.000000] BIOS-e820: [mem 0x00000000ff800000-0x00000000ffffffff] res= erved > [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000087fffffff] usa= ble > > Where 4G is good. Then, > > [ 0.000000] user-defined physical RAM map: > [ 0.000000] user: [mem 0x0000000000000000-0x0000000000093fff] usable > [ 0.000000] user: [mem 0x0000000000094000-0x000000000009ffff] reserved > [ 0.000000] user: [mem 0x00000000000e0000-0x00000000000fffff] reserved > [ 0.000000] user: [mem 0x0000000000100000-0x000000005a7a0fff] usable > [ 0.000000] user: [mem 0x000000005a7a1000-0x000000005b5e0fff] reserved > [ 0.000000] user: [mem 0x000000005b5e1000-0x00000000790fefff] usable > [ 0.000000] user: [mem 0x00000000790ff000-0x00000000791fefff] reserved > [ 0.000000] user: [mem 0x00000000791ff000-0x000000007b5fefff] ACPI NVS > [ 0.000000] user: [mem 0x000000007b5ff000-0x000000007b7fefff] ACPI dat= a > [ 0.000000] user: [mem 0x000000007b7ff000-0x000000007b7fffff] usable > [ 0.000000] user: [mem 0x000000007b800000-0x000000008fffffff] reserved > [ 0.000000] user: [mem 0x00000000ff800000-0x00000000ffffffff] reserved > [ 0.000000] user: [mem 0x0000000100000000-0x00000001ffffffff] persiste= nt (type 12) > [ 0.000000] user: [mem 0x0000000200000000-0x000000087fffffff] usable > > The doc did mention that =E2=80=9CThere seems to be an issue with CONFIG_= KSAN at the moment however.=E2=80=9D > without more detail though. Does disabling CONFIG_RANDOMIZE_BASE help? Maybe that workaround has regressed. Effectively we need to find what is causing the kernel to sometimes be placed in the middle of a custom reserved memmap=3D range.