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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 34AFEC433B4 for ; Tue, 11 May 2021 13:40:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02B8561480 for ; Tue, 11 May 2021 13:40:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230494AbhEKNly (ORCPT ); Tue, 11 May 2021 09:41:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:48528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229921AbhEKNly (ORCPT ); Tue, 11 May 2021 09:41:54 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 85AC76134F; Tue, 11 May 2021 13:40:47 +0000 (UTC) Date: Tue, 11 May 2021 09:40:45 -0400 From: Steven Rostedt To: Yordan Karadzhov Cc: Linux Trace Devel Subject: Re: [PATCH] kernel-shark: Add check for return of ksmodel_get_cpu_front() Message-ID: <20210511094045.1673b76a@gandalf.local.home> In-Reply-To: <2bc740d1-e093-17d1-a9ba-b4319e0ebbfa@gmail.com> References: <20210507093848.72bf0bed@gandalf.local.home> <2bc740d1-e093-17d1-a9ba-b4319e0ebbfa@gmail.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Tue, 11 May 2021 16:25:35 +0300 Yordan Karadzhov wrote: > > You can reproduce this with: > > > > http://rostedt.org/private/trace-no-map.tar.bz2 > > > > diff --git a/src/KsPlotTools.cpp b/src/KsPlotTools.cpp > > index 225dc34..abef5f8 100644 > > --- a/src/KsPlotTools.cpp > > +++ b/src/KsPlotTools.cpp > > @@ -1280,7 +1280,7 @@ void Graph::fillTaskGraph(int sd, int pid) > > false, > > _collectionPtr, > > &index); > > I wonder why this fails? Is it because "pid" is negative? The fix below > is appropriate, however we should detect negative PIDs and abort > plotting much earlier. I believe the issue is that we failed to map which host task goes with which guest vCPUU, and just randomly picked one (or none). I fixed trace-cmd to get the mappings when qemu is not found, and KernelShark works fine on that case. This bug only appears when it can't find the host thread that corresponds to the guest vCPU. -- Steve