Received: by 2002:ac0:a5a6:0:0:0:0:0 with SMTP id m35-v6csp7203102imm; Tue, 28 Aug 2018 08:02:17 -0700 (PDT) X-Google-Smtp-Source: ANB0VdY9eX7w044GPydWA8wVWa5eZO3m97QYyB7F4jq3NmXeURFfYD4QC+Ko9ZKdCvE9V+lzbiYc X-Received: by 2002:a63:5660:: with SMTP id g32-v6mr1887267pgm.227.1535468537796; Tue, 28 Aug 2018 08:02:17 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1535468537; cv=none; d=google.com; s=arc-20160816; b=DOd+LHV9ISa3H3aIhUWFBbiDrIv2yw75KdDEFV5ngHvSUk/tSywTlOUF2D44ecynOc 8qAqPgOUkW7Q50T7lpNAOqIQKhy82NowS8qdHClillGTzupQammyAK94nw37xYLFsuwp xKaUlhUPmbJY3gFkuNuywE8o8Ovg8DfHNQwRos5FkOuuNn/Kyn1bSpgfeX6IDM+SnIbG etpxVEgpJnlQtzQxnX/CRNQniexUI8mTp8ocdu2/ETGpD5g1mD/7bGRmHUTcXMhiz8j3 glBAT4ybbgyv4Ct0tyemh94qXHegvb0vMQVszMLTP6lP6Njzkvj0NMSfxj4D1d8gN6uQ HJuw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:arc-authentication-results; bh=JTR3gH8z8SC06c4kMY4Fd2WJpM8bsrnkCJ/+KBawQs4=; b=IWrAJPd0vTSoxPUeEnfpJrLbQCSgLYUNO4CPQKDl6Raqm1uvD+uOnjf19ddXL1z0UV UpwloMvonb8HOAGFlzynJY2Eegi2rl8Udkh4ZOpQCNkeLZcu4eX7rvC2RT1yhqs6PfMA 6XXNdqOWKR7FARFOzAK4mWMKDALnROdzEy+3Oid0zJaeYcuFHqX3HBRthbAZ15PAdp7f d8E6l1GzsrH4BCzZObRfnH7CD+tDiWyL51dgqE1dWFFjVQUX3iUFNvqsGKf9M3eEksev Y9MsdhVTA10WS5z3v9zjRVS1iAn4M78a9Va47SfyuheMH1Ckt+P0eVMrceLQRkc5VuOy PPsw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id z71-v6si1166244pff.223.2018.08.28.08.02.01; Tue, 28 Aug 2018 08:02:17 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727124AbeH1Sw4 (ORCPT + 99 others); Tue, 28 Aug 2018 14:52:56 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:47047 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726807AbeH1Sw4 (ORCPT ); Tue, 28 Aug 2018 14:52:56 -0400 Received: by mail-lj1-f193.google.com with SMTP id 203-v6so1673906ljj.13 for ; Tue, 28 Aug 2018 08:00:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JTR3gH8z8SC06c4kMY4Fd2WJpM8bsrnkCJ/+KBawQs4=; b=Dzr8fUvpYdpbEGKUTP6eCLE7hXX27l2dCvVPmWdycDvzjg6YswCJEzXaYlw4ynFBM8 15Z9v3omzdJoE7KtyiAwIia2T0Z2dHpVr89YD8W9VeRgi+tWZKGf5dy0FQO1EEVMp8Xl pYQcbilIZy0W+gKPOCgXHpQFfSdUkMCDV4BI1LsL3UWuGJiqgMaJXtdlBiOEOSKIp+Kd SUPXDDvS4UZp0OeXq66BC6+4c47DYjbXwUArnO6OJ29cPPeoVoOiUgtSsut64RaasH02 QjLFmuA9F/Cf3emFnzZZ8FOnRB5B+OWvatT/1SOv/o+mYG005gMZeIxQ7/6ZHuS9tMxB wiLA== X-Gm-Message-State: APzg51DRAWswfR2F8gLsLguOCNewgBn0E6tr5KVKBLYcH/a11FqkALbY SlbDmD0ivqi7R9LS3994aRLUjfmrV//TcT71sJgawA== X-Received: by 2002:a2e:9b04:: with SMTP id u4-v6mr1540858lji.78.1535468450561; Tue, 28 Aug 2018 08:00:50 -0700 (PDT) MIME-Version: 1.0 References: <20180829003539.668e514c@roar.ozlabs.ibm.com> In-Reply-To: <20180829003539.668e514c@roar.ozlabs.ibm.com> From: Matteo Croce Date: Tue, 28 Aug 2018 15:00:14 +0000 Message-ID: Subject: Re: VirtIO console hangs To: Nicholas Piggin Cc: Greg Kroah-Hartman , Jiri Slaby , Michael Ellerman , Benjamin Herrenschmidt , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 28, 2018 at 2:35 PM Nicholas Piggin wrote: > > On Tue, 28 Aug 2018 12:54:08 +0000 > Matteo Croce wrote: > > > With kernel 4.19.0-rc1 virtio_console hangs very often. > > I can always trigger the bug by pasting some characters in the > > terminal window, the console will stop receiving keypresses, but I can > > still see output from the console. > > Stangely, logging in the VM via SSH and sending lot of data to hvc0, > > like 'dmesg >/dev/hvc0' will fix the issue until the next paste. > > > > I did a git bisect and I've found that this is the offending commit, > > reverting it fixes it. > > > > Cheers, > > > > commit ec97eaad1383ab2500fcf9a07ade6044fbcc67f5 > > Author: Nicholas Piggin > > Date: Tue May 1 00:55:54 2018 +1000 > > > > tty: hvc: hvc_poll() break hv read loop > > Thanks for the report. I can't immediately see what the problem > is. Can you try get a stack trace of where it is stuck? > I tried but didn't get one. > Perhaps try this patch if you have time (it's a bit of a shot > in the dark). > Yes it seems to fix. Thanks! -- Matteo Croce per aspera ad upstream