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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 DCA12C433E6 for ; Wed, 27 Jan 2021 17:16:35 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 8EAED64DAD for ; Wed, 27 Jan 2021 17:16:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8EAED64DAD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.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=bd/VkjA16ERKrRKhJHIhDPThfeLI28wWkARXCpc/dCc=; b=neNgNFf61HkKfrKR250HViTTB Y3efcAhFVu+O4jHUjRoXpvGYucK/FnOQ44IFPKb8Yg/sUG9YZE/jyZzKp4jAHjG6A/l/2DzpgEjsh mHhwwau9koG3Gwkb9BMX/rj+Jq/Cidv9yWLVwuuZA6dPVirzLFcWvZaxljfycT847vEJQ1SE3qNzV YFbwLVYaIa9f67vrIELnfdOXZsXPOzxqzWRPAFn8YB4iO97Vrl6rgmfDjBEkL1X3Zbv693wKtPYC2 psIFXiK9Aw0PXIgGELhfsHMDLyB28ngrXiDOnO4NcJA3m+Kx7mO8cyfjx0YypvYtXXBuw5hZQLLZL fLeNoMUjw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4oPb-0002pa-1h; Wed, 27 Jan 2021 17:15:23 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4oPD-0002iK-Ic for linux-arm-kernel@lists.infradead.org; Wed, 27 Jan 2021 17:15:00 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1064364DA9; Wed, 27 Jan 2021 17:14:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611767698; bh=kYY8ilRGfiiSF/WUBVz8wEgrDLz0uywZZmaL40DCVmU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rmFeI+W6PrYomXlVvbXIZRka5UDciU8i6Vx7xWEcLi6pyr5uXzaoYiB3AnLF3QUJD IgU2BFmPJzoBQmiSRsvl60CU8vs3Nl6Jlm+uGxtdprMMBrdn+CY3fXCtUdhmSuD1S1 wlEKhgrjMmLDctSaEbaI/MvRpiCDpWBuzS6kav9YAJTxVOat2ppXKQSVnhXtqbRd29 fqtTWVDxX2mOyaKZT7BAoathVnvzEyYmlY1NDqTAVcNR6tGWC2IneqzfDjYsmv6WDK JTEgrgNi76WNDbETWUIy3PXjyGc8xKBCp7ew1QSEQG8s/voaE/qA43wD4v4uAUsb0n Z1RVa+dpyElvQ== Date: Wed, 27 Jan 2021 17:14:53 +0000 From: Will Deacon To: Dmitry Vyukov Subject: Re: WARNING in __do_kernel_fault Message-ID: <20210127171453.GC358@willie-the-truck> References: <0000000000009bbb7905b9e4a624@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210127_121459_738001_45EBB8D0 X-CRM114-Status: GOOD ( 16.76 ) 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 , syzbot , Catalin Marinas , syzkaller-bugs , LKML , Andrey Konovalov , Dave Martin , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jan 27, 2021 at 06:00:30PM +0100, Dmitry Vyukov wrote: > On Wed, Jan 27, 2021 at 5:56 PM syzbot > wrote: > > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 2ab38c17 mailmap: remove the "repo-abbrev" comment > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=15a25264d00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=ad43be24faf1194c > > dashboard link: https://syzkaller.appspot.com/bug?extid=45b6fce29ff97069e2c5 > > userspace arch: arm64 > > > > Unfortunately, I don't have any reproducer for this issue yet. > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+45b6fce29ff97069e2c5@syzkaller.appspotmail.com > > This happens on arm64 instance with mte enabled. > There is a GPF in reiserfs_xattr_init on x86_64 reported: > https://syzkaller.appspot.com/bug?id=8abaedbdeb32c861dc5340544284167dd0e46cde > so I would assume it's just a plain NULL deref. Is this WARNING not > indicative of a kernel bug? Or there is something special about this > particular NULL deref? Congratulations, you're the first person to trigger this warning! This fires if we take an unexpected data abort in the kernel but when we get into the fault handler the page-table looks ok (according to the CPU via an 'AT' instruction). Are you using QEMU system emulation? Perhaps its handling of AT isn't quite right. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel