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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_MUTT 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 8CC92C4321D for ; Wed, 22 Aug 2018 09:08:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E4AC214DD for ; Wed, 22 Aug 2018 09:08:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="XVm80Tbv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E4AC214DD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728574AbeHVMcd (ORCPT ); Wed, 22 Aug 2018 08:32:33 -0400 Received: from merlin.infradead.org ([205.233.59.134]:48482 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728208AbeHVMcc (ORCPT ); Wed, 22 Aug 2018 08:32:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender: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=2MlIghxPQNJMxSSvYcJQ6trD5NkfV7M80jjYoTVNm1k=; b=XVm80Tbv0ALcd0XUwYMtmRmWR 3QXLNvlPIBBwbxoKRPeugLbDxPOWJ0qp8cBMXWy4k8SIu2HQl7kEL2ikye5jMZxJJu8K/RtFVcvUY Nu9W5GMNJFDe7i5ESrjoV1PDaZnr7g46L7JRq0NzhAZA3uP2A0oHRxcFxQAdbU0FVdrMmyh9zU7OT mNFWL2/P/B+QJYv6QmxqRdguMfTMAxWpYEt0AeIjC6Mv0CdfKeSdFWs81aQNa5hJpCx8J/TH1neeP OCQRkcYDoGFifXylADdq3j30/SFYpJnPkuG/5t/A17O1qIW3HOPAQFSx6HdDCd6/TdCE4JtFtSQL7 7w0vdWaDw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fsP7p-0007D0-AZ; Wed, 22 Aug 2018 09:08:25 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id EF2622025D75D; Wed, 22 Aug 2018 11:08:23 +0200 (CEST) Date: Wed, 22 Aug 2018 11:08:23 +0200 From: Peter Zijlstra To: syzbot Cc: dvhart@infradead.org, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, pbonzini@redhat.com, rkrcmar@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org Subject: Re: general protection fault in finish_task_switch (2) Message-ID: <20180822090823.GT24124@hirez.programming.kicks-ass.net> References: <00000000000035c2ed057315bf85@google.com> <0000000000006e87360573f8b328@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0000000000006e87360573f8b328@google.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 21, 2018 at 02:28:02PM -0700, syzbot wrote: > syzbot has found a reproducer for the following crash on: > > HEAD commit: 778a33959a8a Merge tag 'please-pull-noboot' of git://git.k.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=14a5385a400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=214e4990bd49329f > dashboard link: https://syzkaller.appspot.com/bug?extid=1f56df64bfb3c29dde6f > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > userspace arch: i386 > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=13ffa561400000 FWIW the lack of whitespace between "repro:" and the URL makes it hard to copy paste. > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10023961400000 > RIP: 0010:__fire_sched_in_preempt_notifiers kernel/sched/core.c:2481 That repro thing does something dodgy with KVM, which then corrupts the premption notifier thing. I'm sufficiently KVM clueless to not really know where to start looking though..