From owner-freebsd-current@FreeBSD.ORG Thu Mar 13 10:17:10 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 3C3AD6FA for ; Thu, 13 Mar 2014 10:17:10 +0000 (UTC) Received: from mail-we0-x235.google.com (mail-we0-x235.google.com [IPv6:2a00:1450:400c:c03::235]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id CB770245 for ; Thu, 13 Mar 2014 10:17:09 +0000 (UTC) Received: by mail-we0-f181.google.com with SMTP id q58so619079wes.26 for ; Thu, 13 Mar 2014 03:17:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:sender:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=/eiFP1aNzhBh95B4ccikgt9whEpBNRMQMvq/4K7bBqA=; b=FGo8BmIh51hd02DjLkleyG3aWUPZRNXcyDk8lfVgTxilYIrMnO1W4W7yfmarb2oC0x VyHq/285wwp/7H3Pjh4s2mFCg40boyimvP/8dYD1nqYr9Hxlb49r6+2+gJJcM+W9uNqe shZAoP/A1WHLYMMQEjndAPCJ1bZ+9U9DNhbiDkgt2AgrUkWTeXV+IhSPAmgi6HoRCo4+ YOPK7y8MAbgAITyCn7Rl8h92BM0MVLQbVLB6QnrnLCr2CfKt3W8XGR9ZBruJNsjLvsq6 q/Q/zvIsFLaeQuoVg1OD+9zc90f+PD0xvd4mSuY049+JXaUgJuWYeQZo/hCe2QV35Qw/ ZWEA== MIME-Version: 1.0 X-Received: by 10.180.12.233 with SMTP id b9mr944968wic.8.1394705828189; Thu, 13 Mar 2014 03:17:08 -0700 (PDT) Sender: asmrookie@gmail.com Received: by 10.217.61.196 with HTTP; Thu, 13 Mar 2014 03:17:08 -0700 (PDT) In-Reply-To: <532177E0.5010905@delphij.net> References: <531EBFDC.3010608@delphij.net> <532177E0.5010905@delphij.net> Date: Thu, 13 Mar 2014 11:17:08 +0100 X-Google-Sender-Auth: LhpQ60-bN9329NP_zUhuLbkFVZE Message-ID: Subject: Re: processes stuck in vmo_de state From: Attilio Rao To: Xin LI Content-Type: text/plain; charset=UTF-8 Cc: FreeBSD Current , Alexander Motin X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 13 Mar 2014 10:17:10 -0000 On Thu, Mar 13, 2014 at 10:18 AM, Xin Li wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 > > Hi, > > It looks like there is a regression (or a regression that gets exposed > by some new feature) that is related to time-keeping or timecounter, > although I'm not yet familiar with the related code to tell if my > conclusion was right or not. > > The problem I observed is that when system boots up, it sometimes > hangs and pressing ^T on console tells me that sleep(1) is running > with 0 second out of 1 second, but the 'real' part of the output is > smaller than 1 or sometimes negative. > > For some reason the console may stop giving any output, but trapping > into debugger would unblock it sometimes. > > When sh(1) stuck in 'vmo_de' state, it would never recover from that > and a hard reset is necessary. If sleeps are not being serviced 'vmo_de' "deadlocks" makes sense because it is a sleep(1) condition. What is softclock doing at the time the deadlock happens? Attilio -- Peace can only be achieved by understanding - A. Einstein