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=-6.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 07193C433E0 for ; Fri, 22 Jan 2021 15:33:17 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 87169206A4 for ; Fri, 22 Jan 2021 15:33:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 87169206A4 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=xenproject.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.72882.131369 (Exim 4.92) (envelope-from ) id 1l2yQs-0002VP-04; Fri, 22 Jan 2021 15:33:06 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 72882.131369; Fri, 22 Jan 2021 15:33:05 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l2yQr-0002VI-TJ; Fri, 22 Jan 2021 15:33:05 +0000 Received: by outflank-mailman (input) for mailman id 72882; Fri, 22 Jan 2021 15:33:04 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l2yQq-0002VD-BE for xen-devel@lists.xenproject.org; Fri, 22 Jan 2021 15:33:04 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l2yQp-000219-Sg for xen-devel@lists.xenproject.org; Fri, 22 Jan 2021 15:33:03 +0000 Received: from iwj (helo=mariner.uk.xensource.com) by xenbits.xenproject.org with local-bsmtp (Exim 4.92) (envelope-from ) id 1l2yQp-0007HN-Rt for xen-devel@lists.xenproject.org; Fri, 22 Jan 2021 15:33:03 +0000 Received: from iwj by mariner.uk.xensource.com with local (Exim 4.89) (envelope-from ) id 1l2yQm-000462-Ll; Fri, 22 Jan 2021 15:33:00 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xenproject.org; s=20200302mail; h=References:In-Reply-To:Subject:Cc:To:Date :Message-ID:Content-Transfer-Encoding:Content-Type:MIME-Version:From; bh=baHlpmCM+7LXwEs3U+LjvwJddk49UkxH33O3v3qMIbY=; b=lWQgxKSasa2UpD/MI4HM33IeUD l7+wCZjmUia/Hmvc2JXUrEam30lL2RQo5ENkEkGDGJT73Ep9Ka++6xYpIpePLZ44KdE0VGFcpAfXn 1LK1SPutjdkXTy/pO9r5rh/D1gxKYzL6iVzKH9wS4Ejg2WCuVqB7dVHYRYxs7Fc1y4xU=; From: Ian Jackson MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 Content-Transfer-Encoding: 8bit Message-ID: <24586.61484.451595.44272@mariner.uk.xensource.com> Date: Fri, 22 Jan 2021 15:33:00 +0000 To: Andrew Cooper Cc: Xen-devel , =?iso-8859-2?Q?Micha=B3_Leszczy=F1ski?= , Wei Liu , Tamas K Lengyel Subject: Re: [PATCH v7 08/10] tools/misc: Add xen-vmtrace tool In-Reply-To: <20210121212718.2441-9-andrew.cooper3@citrix.com> References: <20210121212718.2441-1-andrew.cooper3@citrix.com> <20210121212718.2441-9-andrew.cooper3@citrix.com> X-Mailer: VM 8.2.0b under 24.5.1 (i686-pc-linux-gnu) Andrew Cooper writes ("[PATCH v7 08/10] tools/misc: Add xen-vmtrace tool"): > From: Michał Leszczyński ... > + if ( signal(SIGINT, int_handler) == SIG_ERR ) > + err(1, "Failed to register signal handler\n"); How bad is it if this signal handler is not effective ? > + if ( xc_vmtrace_disable(xch, domid, vcpu) ) > + perror("xc_vmtrace_disable()"); I guess the tracing will remain on, pointlessly, which has a perf impact but nothing else ? How is it possible for the user to clean this up ? Also: at the very least, you need to trap SIGTERM SIGHUP SIGPIPE. It would be good to exit with the right signal by re-raising it. > +static volatile int interrupted = 0; sig_atomic_t Ian.