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=-10.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 A4EB7C433E0 for ; Fri, 19 Mar 2021 10:11:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5E62464E20 for ; Fri, 19 Mar 2021 10:11:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230096AbhCSKLI (ORCPT ); Fri, 19 Mar 2021 06:11:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229447AbhCSKLC (ORCPT ); Fri, 19 Mar 2021 06:11:02 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEE4AC06174A for ; Fri, 19 Mar 2021 03:10:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=KdBbV8/OXWtTCcyd1IKKVkbLO4A09JYxnlTNuWCStG4=; b=VeLnxRR/h1WJz4HSq3i94YtI2 nFJG+kq846qcwC1V/Gz8Z+p4etwrafqoDtXTjLCWhtRvtRSGCh3yD9kpPsJl91OJy7w8C6kPI6xCr P8b3urGPiSgOWfFiu49lol13VD1pM4U/k2p8ZIdrWacwpJEKEz7WfHl+Xu8NR/r6QQhTiOu4hJmc0 eL4j3TIzjt7+mb8jInW7ezhTWyQHKn3iSo88D7EU7PEhddtYwl9CL42hYUZ388YOf3ivV0NFQ0CQO 24fzhwUEk4pvsI/sDC7gA/0mFuL6FT6HnDCjgmRzxC12XPGseZcf9jprql1PZn53VZCICRkDRqMGc n9m0R2IOA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:51474) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lNC5e-0004HU-S1; Fri, 19 Mar 2021 10:10:46 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1lNC5b-0000Ue-8W; Fri, 19 Mar 2021 10:10:43 +0000 Date: Fri, 19 Mar 2021 10:10:43 +0000 From: Russell King - ARM Linux admin To: Dmitry Vyukov Cc: syzbot , Mark Rutland , Arnd Bergmann , Linux ARM , Alexandre Chartre , LKML , Masami Hiramatsu , Peter Zijlstra , syzkaller-bugs , Thomas Gleixner Subject: Re: [syzbot] upstream boot error: WARNING in __context_tracking_enter Message-ID: <20210319101043.GU1463@shell.armlinux.org.uk> References: <0000000000004f14c105bde08f75@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: Russell King - ARM Linux admin Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 19, 2021 at 10:54:48AM +0100, Dmitry Vyukov wrote: > .On Fri, Mar 19, 2021 at 10:44 AM syzbot > wrote: > > syzbot found the following issue on: > > > > HEAD commit: 8b12a62a Merge tag 'drm-fixes-2021-03-19' of git://anongit.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=17e815aed00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=cfeed364fc353c32 > > dashboard link: https://syzkaller.appspot.com/bug?extid=f09a12b2c77bfbbf51bd > > userspace arch: arm > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+f09a12b2c77bfbbf51bd@syzkaller.appspotmail.com > > > +Mark, arm > It did not get far with CONFIG_CONTEXT_TRACKING_FORCE (kernel doesn't boot). It seems that the path: context_tracking_user_enter() user_enter() context_tracking_enter() __context_tracking_enter() vtime_user_enter() expects preemption to be disabled. It effectively is, because local interrupts are disabled by context_tracking_enter(). However, the requirement for preemption to be disabled is not documented... so shrug. Maybe someone can say what the real requirements are here. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!