From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:34523) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIrwn-0000JA-6q for qemu-devel@nongnu.org; Tue, 23 Apr 2019 05:42:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hIrwd-0007lB-T9 for qemu-devel@nongnu.org; Tue, 23 Apr 2019 05:42:35 -0400 Date: Tue, 23 Apr 2019 10:42:17 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Message-ID: <20190423094217.GC6022@redhat.com> Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] =?utf-8?q?question=EF=BC=9A_Does_qemu-pr-helper_hav?= =?utf-8?q?e_its_own_log_files=EF=BC=9F?= List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jie Wang Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, "Zhangbo (Oscar)" , "Fangyi (C)" On Tue, Apr 23, 2019 at 11:12:40AM +0800, Jie Wang wrote: > =C2=A0Does qemu-pr-helper have its own log files=EF=BC=9F When QEMU launches it, i think it just inherits stdout/err from QEMU itself, so errors appear mixed into QEMU's stdout output. When libvirt launches it, there stdout is connected to /dev/null and stderr is connected to a pipe which libvirt closes almost immediately. This means any errors are lost as any attempt to write to stderr will get EPIPE :-( Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :| 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=-2.3 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 C53FEC10F14 for ; Tue, 23 Apr 2019 09:43:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 96244206BA for ; Tue, 23 Apr 2019 09:43:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 96244206BA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:50800 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIrxY-0000Zz-CU for qemu-devel@archiver.kernel.org; Tue, 23 Apr 2019 05:43:28 -0400 Received: from eggs.gnu.org ([209.51.188.92]:34523) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIrwn-0000JA-6q for qemu-devel@nongnu.org; Tue, 23 Apr 2019 05:42:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hIrwd-0007lB-T9 for qemu-devel@nongnu.org; Tue, 23 Apr 2019 05:42:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50110) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hIrwX-0007jX-Ac; Tue, 23 Apr 2019 05:42:25 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 03F8EC02E60C; Tue, 23 Apr 2019 09:42:23 +0000 (UTC) Received: from redhat.com (ovpn-112-50.ams2.redhat.com [10.36.112.50]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 27C6B1A913; Tue, 23 Apr 2019 09:42:20 +0000 (UTC) Date: Tue, 23 Apr 2019 10:42:17 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Jie Wang Message-ID: <20190423094217.GC6022@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Tue, 23 Apr 2019 09:42:23 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] =?utf-8?q?question=EF=BC=9A_Does_qemu-pr-helper_hav?= =?utf-8?q?e_its_own_log_files=EF=BC=9F?= X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: "Zhangbo \(Oscar\)" , qemu-devel@nongnu.org, qemu-block@nongnu.org, "Fangyi \(C\)" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190423094217.W_4TDnxtNXR9K5GJeAOPNpawSpYBRQIhbpFj2dOZtrE@z> On Tue, Apr 23, 2019 at 11:12:40AM +0800, Jie Wang wrote: > =C2=A0Does qemu-pr-helper have its own log files=EF=BC=9F When QEMU launches it, i think it just inherits stdout/err from QEMU itself, so errors appear mixed into QEMU's stdout output. When libvirt launches it, there stdout is connected to /dev/null and stderr is connected to a pipe which libvirt closes almost immediately. This means any errors are lost as any attempt to write to stderr will get EPIPE :-( Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :|