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=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 31E36C282DB for ; Mon, 21 Jan 2019 09:26:01 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 647FA20989 for ; Mon, 21 Jan 2019 09:26:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="FspUHSpg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 647FA20989 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43jmPd1m6JzDqXK for ; Mon, 21 Jan 2019 20:25:57 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=google.com (client-ip=2607:f8b0:4864:20::d43; helo=mail-io1-xd43.google.com; envelope-from=dvyukov@google.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="FspUHSpg"; dkim-atps=neutral Received: from mail-io1-xd43.google.com (mail-io1-xd43.google.com [IPv6:2607:f8b0:4864:20::d43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43jmMf6wvzzDqTC for ; Mon, 21 Jan 2019 20:24:14 +1100 (AEDT) Received: by mail-io1-xd43.google.com with SMTP id s8so3541056iob.13 for ; Mon, 21 Jan 2019 01:24:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=OL2n5Xw7y8Ptr0DjBBqoBVn5ATX7sgHlxy4qXLn+gjs=; b=FspUHSpgPEzwu1muclAAi7XviMZms13m3cDHuKxYXJ1txn+rRvpIutGfSdYUg7uztB xf0plqq0jVHk+Pma9VT7cern26/a8LJVbBatAa3FYL3i5PBIOHtm56/rU9RGR2aoG+aS qBasWBA/Rf93rMpK4ZyhYU2beT1DCU5/OgeFih4+RDeMdtTAkWX5eF2E5Fg9/bp2jwy5 l02kCcVUVVtUEnM85o34JZc0TVb8sMXotrDgNecM1ButMpxJXVUpMt8ZVp2txQ+dq65o X6EDHO4CRm8RBQwadx4ejWA7kEK1d/UA6v3wT6M+YKVf2K1mmZn6ypDjll8rRH1v6BaZ DqYQ== 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=OL2n5Xw7y8Ptr0DjBBqoBVn5ATX7sgHlxy4qXLn+gjs=; b=jPEIkmsHXNM+qYiMIswY0ya8eB2XicLgnr/eSYjLDV5iPthaLLZLg1Tl3r32rsyRX3 /mXIYAVPLUqBbnJa0lPi09bHl9tuK+yQfsY/PN117sUTo8LwSzGycjeAnBW+/LXzJxOZ 7xRWM/0fO3TJpDRtEmxk7mVfO0OddPniiJUrOsU9L+VWFr6rg2fKaROFKPKqEaXjAU8B Kk+6Kfckd61n2g5+QjdEvou4ClSQ/q7TA9ZPZr6rN7DOfl5ctV2O8t+1izgBUcyEky/h 8G5Hh5ss7kYmeh3JOx1kZj7LqqYwave7/6ooSu2MpS8U3klxgnAU4WxdLmmUGEYsH9w+ oMQA== X-Gm-Message-State: AJcUukeZzUadGPivQy/gHKq9uI4Yo4w5JJON7+915PTLnUWDLJE4b1hA MsGotmAoGpzcP4APOWrur5TIjsnqCSiQ+nnjk80KRw== X-Google-Smtp-Source: ALg8bN6493yX5n0Sowdnesa/q/XbYafkPUw9euh9B+RBhmtez05eHYlS1J4VDNJ67eWt65/+x40iKxqMYkrOW49HbY0= X-Received: by 2002:a5d:8491:: with SMTP id t17mr16118491iom.11.1548062652245; Mon, 21 Jan 2019 01:24:12 -0800 (PST) MIME-Version: 1.0 References: <935f9f83393affb5d55323b126468ecb90373b88.1547289808.git.christophe.leroy@c-s.fr> <8d433501-a5a7-8e3b-03f7-ccdd0f8622e1@c-s.fr>

In-Reply-To: From: Dmitry Vyukov Date: Mon, 21 Jan 2019 10:24:01 +0100 Message-ID: Subject: Re: [PATCH v3 3/3] powerpc/32: Add KASAN support To: Christophe Leroy Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Aneesh Kumar K.V" , LKML , Nicholas Piggin , Linux-MM , Paul Mackerras , kasan-dev , Andrey Ryabinin , Alexander Potapenko , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Jan 21, 2019 at 9:37 AM Christophe Leroy wrote: > > > > Le 21/01/2019 =C3=A0 09:30, Dmitry Vyukov a =C3=A9crit : > > On Mon, Jan 21, 2019 at 8:17 AM Christophe Leroy > > wrote: > >> > >> > >> > >> Le 15/01/2019 =C3=A0 18:23, Andrey Ryabinin a =C3=A9crit : > >>> > >>> > >>> On 1/12/19 2:16 PM, Christophe Leroy wrote: > >>> > >>>> +KASAN_SANITIZE_early_32.o :=3D n > >>>> +KASAN_SANITIZE_cputable.o :=3D n > >>>> +KASAN_SANITIZE_prom_init.o :=3D n > >>>> + > >>> > >>> Usually it's also good idea to disable branch profiling - define DISA= BLE_BRANCH_PROFILING > >>> either in top of these files or via Makefile. Branch profiling redefi= nes if() statement and calls > >>> instrumented ftrace_likely_update in every if(). > >>> > >>> > >>> > >>>> diff --git a/arch/powerpc/mm/kasan_init.c b/arch/powerpc/mm/kasan_in= it.c > >>>> new file mode 100644 > >>>> index 000000000000..3edc9c2d2f3e > >>> > >>>> +void __init kasan_init(void) > >>>> +{ > >>>> + struct memblock_region *reg; > >>>> + > >>>> + for_each_memblock(memory, reg) > >>>> + kasan_init_region(reg); > >>>> + > >>>> + pr_info("KASAN init done\n"); > >>> > >>> Without "init_task.kasan_depth =3D 0;" kasan will not repot bugs. > >>> > >>> There is test_kasan module. Make sure that it produce reports. > >>> > >> > >> Thanks for the review. > >> > >> Now I get the following very early in boot, what does that mean ? > > > > This looks like an instrumented memset call before kasan shadow is > > mapped, or kasan shadow is not zeros. Does this happen before or after > > mapping of kasan_early_shadow_page? > > This is after the mapping of kasan_early_shadow_page. > > > This version seems to miss what x86 code has to clear the early shadow: > > > > /* > > * kasan_early_shadow_page has been used as early shadow memory, thus > > * it may contain some garbage. Now we can clear and write protect it, > > * since after the TLB flush no one should write to it. > > */ > > memset(kasan_early_shadow_page, 0, PAGE_SIZE); > > In the early part, kasan_early_shadow_page is mapped read-only so I > assumed this reset of its content was unneccessary. > > I'll try with it. > > Christophe As far as I understand machine memory contains garbage after boot, and that page needs to be all 0's so we need to explicitly memset it. > >> [ 0.000000] KASAN init done > >> [ 0.000000] > >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > >> [ 0.000000] BUG: KASAN: unknown-crash in memblock_alloc_try_nid+0xd= 8/0xf0 > >> [ 0.000000] Write of size 68 at addr c7ff5a90 by task swapper/0 > >> [ 0.000000] > >> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted > >> 5.0.0-rc2-s3k-dev-00559-g88aa407c4bce #772 > >> [ 0.000000] Call Trace: > >> [ 0.000000] [c094ded0] [c016c7e4] > >> print_address_description+0x1a0/0x2b8 (unreliable) > >> [ 0.000000] [c094df00] [c016caa0] kasan_report+0xe4/0x168 > >> [ 0.000000] [c094df40] [c016b464] memset+0x2c/0x4c > >> [ 0.000000] [c094df60] [c08731f0] memblock_alloc_try_nid+0xd8/0xf0 > >> [ 0.000000] [c094df90] [c0861f20] mmu_context_init+0x58/0xa0 > >> [ 0.000000] [c094dfb0] [c085ca70] start_kernel+0x54/0x400 > >> [ 0.000000] [c094dff0] [c0002258] start_here+0x44/0x9c > >> [ 0.000000] > >> [ 0.000000] > >> [ 0.000000] Memory state around the buggy address: > >> [ 0.000000] c7ff5980: e2 a1 87 81 bd d4 a5 b5 f8 8d 89 e7 72 bc 20= 24 > >> [ 0.000000] c7ff5a00: e7 b9 c1 c7 17 e9 b4 bd a4 d0 e7 a0 11 15 a5= b5 > >> [ 0.000000] >c7ff5a80: b5 e1 83 a5 2d 65 31 3f f3 e5 a7 ef 34 b5 69= b5 > >> [ 0.000000] ^ > >> [ 0.000000] c7ff5b00: 21 a5 c1 c1 b4 bf 2d e5 e5 c3 f5 91 e3 b8 a1= 34 > >> [ 0.000000] c7ff5b80: ad ef 23 87 3d a6 ad b5 c3 c3 80 b7 ac b1 1f= 37 > >> [ 0.000000] > >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > >> [ 0.000000] Disabling lock debugging due to kernel taint > >> [ 0.000000] MMU: Allocated 76 bytes of context maps for 16 contexts > >> [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: = 8176 > >> [ 0.000000] Kernel command line: console=3DttyCPM0,115200N8 > >> ip=3D192.168.2.7:192.168.2.2::255.0.0.0:vgoip:eth0:off kgdboc=3DttyCPM= 0 > >> [ 0.000000] Dentry cache hash table entries: 16384 (order: 2, 65536 > >> bytes) > >> [ 0.000000] Inode-cache hash table entries: 8192 (order: 1, 32768 b= ytes) > >> [ 0.000000] Memory: 99904K/131072K available (7376K kernel code, 52= 8K > >> rwdata, 1168K rodata, 576K init, 4623K bss, 31168K reserved, 0K > >> cma-reserved) > >> [ 0.000000] Kernel virtual memory layout: > >> [ 0.000000] * 0xffefc000..0xffffc000 : fixmap > >> [ 0.000000] * 0xf7c00000..0xffc00000 : kasan shadow mem > >> [ 0.000000] * 0xf7a00000..0xf7c00000 : consistent mem > >> [ 0.000000] * 0xf7a00000..0xf7a00000 : early ioremap > >> [ 0.000000] * 0xc9000000..0xf7a00000 : vmalloc & ioremap > >> > >> > >> Christophe