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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 84506C48BD4 for ; Tue, 25 Jun 2019 14:01:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32BC7213F2 for ; Tue, 25 Jun 2019 14:01:38 +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="RRdkM+k8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727975AbfFYOBg (ORCPT ); Tue, 25 Jun 2019 10:01:36 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:43260 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726532AbfFYOBg (ORCPT ); Tue, 25 Jun 2019 10:01:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=3PwAJTk+sBAtZBFdoInQvViDTwMss4ggvuDLkO528o0=; b=RRdkM+k8boZ+7CU1YF7K5iZbr NbapzGr+V4hA8g0ypn2aLr7G4woPUR7CB6AC2XW6Q9jhCJdsFbhgnnId0OZI4NCf+eQtE1DSZ47Fs SeKtO1sT3k+Co4WIUOA+2K3y0Ff0ckmHJksEVk/qIc0rxFzc8+Ngt4lgo7nIR8tav8gFRc3Dp3kGO BFQY19wvdnxhLuEhl/ke6dEnTiQDdCuuaiI46ARZHLooqCfrhLuHdwB/2F3gtxnFk4Xzw0lErOdp9 dZTcNQRNZQ48xY0ko2kpezSMMzLbdP/cX6VMCh7Ox3WFKWJAwoAzIAyEswpEQ8kZ444zYzPvP+Hh0 rhcuizvgw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hfm0p-0006aX-27; Tue, 25 Jun 2019 14:01:31 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 65DCF202B4821; Tue, 25 Jun 2019 16:01:29 +0200 (CEST) Date: Tue, 25 Jun 2019 16:01:29 +0200 From: Peter Zijlstra To: Dmitry Vyukov Cc: Thomas Gleixner , syzbot , LKML , syzkaller-bugs Subject: Re: WARNING in mark_lock Message-ID: <20190625140129.GB3419@hirez.programming.kicks-ass.net> References: <0000000000005aedf1058c1bf7e8@google.com> <20190625110301.GX3419@hirez.programming.kicks-ass.net> <20190625110609.GA3463@hirez.programming.kicks-ass.net> 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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 25, 2019 at 02:07:42PM +0200, Dmitry Vyukov wrote: > On Tue, Jun 25, 2019 at 1:06 PM Peter Zijlstra wrote: > > > > On Tue, Jun 25, 2019 at 01:03:01PM +0200, Peter Zijlstra wrote: > > > On Tue, Jun 25, 2019 at 08:20:56AM +0200, Thomas Gleixner wrote: > > > > On Mon, 24 Jun 2019, syzbot wrote: > > > > > > > > syzbot found the following crash on: > > > > > > > > > > HEAD commit: dc636f5d Add linux-next specific files for 20190620 > > > > > git tree: linux-next > > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=162b68b1a00000 > > > > syzcaller folks; why doesn't the above link include the actual kernel > > boot, but only the userspace bits starting at syzcaller start? > > > > I was trying to figure out the setup, but there's not enough information > > here. > > Hi Peter, > > Usually there is too much after-boot output, so boot output is evicted > anyway even if was preserved initially. Also usually it's not > important (this is the first time this comes up). And also > structurally boot is a separate procedure in syzkaller VM abstraction, > a machine is booted, output is analyzed for potential crashes, then > the machine is considered in a known good state and then some workload > is started as a separate procedure and new output capturing starts > from this point again. Ah, for my own machines I spool all serial console output to a file, everything is preserved until logrotate kills it after a week or so. There is no distinction between boot and anything else, everything that goes to serial (and I make sure everything does) lands together. > What info are you interested in? Can if be obtained after boot? I was interested in the kernel commandline; and in particular the nohz_full configuration if any.