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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 9A2F9C433E0 for ; Wed, 27 May 2020 13:41:18 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 651372078B for ; Wed, 27 May 2020 13:41:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="o7xnAVSt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 651372078B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=/FG+LbiDf1Hti5IBIjGQsMdTb6AxsvIq2F/5aWCJU0I=; b=o7xnAVStzUVNdj VcwhZ1Wur4DnIpUyUUf4R89hrOIbCZ8Vmz5DQs40Jx3gtCIWkSY0NgBlFmlUpBlecU9E0hoxNGHxU UBlg0xnehFTkWT5z5mJMJ0lVPB/ElK/cEMtv8pwsXCefUtP7IFgsEqT2Nq2v8boOKW2fa1X0AugnO tIXQR08qXdr+ynEDJLI6w0Oo6wQ0Voje6ywnoOb7k/FJcH2RLPwi28edMiDDPjA/fMA9W8v0z52oW 1K57IdgH/xIo19MExWovHBcd2rhn46MjSLmG9vKbdJYXFGCisGZtIp/O5IsDT2wM8aJVzqi+aRkEt iQ1JTxsrQT+pgFoWqctg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdwJ4-0006K1-0g; Wed, 27 May 2020 13:41:18 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdwJ0-0006Iu-OG for linux-arm-kernel@lists.infradead.org; Wed, 27 May 2020 13:41:16 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 163A755D; Wed, 27 May 2020 06:41:11 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id ECA433F305; Wed, 27 May 2020 06:41:09 -0700 (PDT) Date: Wed, 27 May 2020 14:41:04 +0100 From: Lorenzo Pieralisi To: Will Deacon Subject: Re: arm64/acpi: NULL dereference reports from UBSAN at boot Message-ID: <20200527134104.GA16115@e121166-lin.cambridge.arm.com> References: <20200521100952.GA5360@willie-the-truck> <20200521173738.GA29590@e121166-lin.cambridge.arm.com> <20200526202157.GE2206@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200526202157.GE2206@willie-the-truck> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200527_064114_834101_9545F2E4 X-CRM114-Status: GOOD ( 20.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, rjw@rjwysocki.net, ndesaulniers@google.com, linux-kernel@vger.kernel.org, guohanjun@huawei.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 26, 2020 at 09:21:57PM +0100, Will Deacon wrote: > Hi Lorenzo, Hanjun, [+Nick] > > On Thu, May 21, 2020 at 06:37:38PM +0100, Lorenzo Pieralisi wrote: > > On Thu, May 21, 2020 at 11:09:53AM +0100, Will Deacon wrote: > > > Hi folks, > > > > > > I just tried booting the arm64 for-kernelci branch under QEMU (version > > > 4.2.50 (v4.2.0-779-g4354edb6dcc7)) with UBSAN enabled, and I see a > > > couple of NULL pointer dereferences reported at boot. I think they're > > > both GIC related (log below). I don't see a panic with UBSAN disabled, > > > so something's fishy here. > > > > May I ask you the QEMU command line please - just to make sure I can > > replicate it. > > As it turns out, I'm only able to reproduce this when building with Clang, > but I don't know whether that's because GCC is missing something of Clang > is signalling a false positive. You also don't need all of those whacky > fuzzing options enabled. > > Anyway, to reproduce: > > $ git checkout for-next/kernelci > $ make ARCH=arm64 CC=clang CROSS_COMPILE=aarch64-linux-gnu- defconfig > > $ make ARCH=arm64 CC=clang CROSS_COMPILE=aarch64-linux-gnu- Image > > I throw that at QEMU using: > > qemu-system-aarch64 -M virt -machine virtualization=true \ > -machine virt,gic-version=3 \ > -cpu max,sve=off -smp 2 -m 4096 \ > -drive if=pflash,format=raw,file=efi.img,readonly \ > -drive if=pflash,format=raw,file=varstore.img \ > -drive if=virtio,format=raw,file=disk.img \ > -device virtio-scsi-pci,id=scsi0 \ > -device virtio-rng-pci \ > -device virtio-net-pci,netdev=net0 \ > -netdev user,id=net0,hostfwd=tcp::8222-:22 \ > -nographic \ > -kernel ~/work/linux/arch/arm64/boot/Image \ > -append "earlycon root=/dev/vda2" > > I built QEMU a while ago according to: > > https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/docs/qemu/qemu-arm64-howto.html > > and its version 4.2.50 (v4.2.0-779-g4354edb6dcc7). > > My clang is version 11.0.1. Thanks a lot Will. I *think* I was right - it is the ACPI_OFFSET() macro: #define ACPI_OFFSET(d, f) ACPI_PTR_DIFF (&(((d *) 0)->f), (void *) 0) that triggers the warnings (I suspected it because at least in one of the warnings I could not see any dereference of any dynamically allocated data). Now on what to do with it - thoughts welcome. Lorenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel