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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 9380BC3A5A9 for ; Mon, 4 May 2020 20:00:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6EB9A20707 for ; Mon, 4 May 2020 20:00:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726410AbgEDUAM (ORCPT ); Mon, 4 May 2020 16:00:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:53890 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726111AbgEDUAM (ORCPT ); Mon, 4 May 2020 16:00:12 -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 55496206A5; Mon, 4 May 2020 20:00:11 +0000 (UTC) Date: Mon, 4 May 2020 16:00:09 -0400 From: Steven Rostedt To: "Tzvetomir Stoyanov (VMware)" Cc: linux-trace-devel@vger.kernel.org Subject: Re: [PATCH v2 1/4] trace-cmd: Fix trace-cmd report crash while displaying trace.dat in specific use case Message-ID: <20200504160009.2223160a@gandalf.local.home> In-Reply-To: <20200504062711.107867-2-tz.stoyanov@gmail.com> References: <20200504062711.107867-1-tz.stoyanov@gmail.com> <20200504062711.107867-2-tz.stoyanov@gmail.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Mon, 4 May 2020 09:27:08 +0300 "Tzvetomir Stoyanov (VMware)" wrote: > The trace-cmd report command crashes while displaying a file recorded with "--proc-map" and "-B" options: > #trace-cmd record --proc-map -B test -e sched -F sleep 1 > The "--proc-map" options saves the address map of "sleep" into the trace.dat file. This > information is used by KernelShark. The "-B" options traces the specified events into a > ftrace instance "test". > When such file is opened using libtracecmd APIs, the proc-map is parsed and saved into > a tracecmd_input handler, as linked list "pid_maps". Later, when the ftrace instance > "test" is parsed, a copy of this handler is used to fill it with the instance's trace data. > Both tracecmd_input handlers share the same "pid_maps" list, thus leads to a double > free of the list, when handlers are destroyed. > As this "pid_maps" is not used in ftrace buffers, the "pid_maps" list of the copy can be > initialized to NULL. > > Signed-off-by: Tzvetomir Stoyanov (VMware) FYI, I changed the subject and body to this: trace-cmd: Fix trace-cmd report crash while displaying trace.dat with --proc-map and -B options The trace-cmd report command crashes while displaying a file recorded with "--proc-map" and "-B" options: # trace-cmd record --proc-map -B test -e sched -F sleep 1 The "--proc-map" options saves the address map of "sleep" into the trace.dat file. This information is used by KernelShark. The "-B" option traces the specified events into a ftrace instance "test". When such a file is opened using libtracecmd APIs, the proc-map is parsed and saved into a tracecmd_input handler, as linked list "pid_maps". Later, when the ftrace instance "test" is parsed, a copy of this handler is used to fill it with the instance's trace data. Both tracecmd_input handlers share the same "pid_maps" list, thus leads to a double free of the list when the handlers are destroyed. As this "pid_maps" is not used in ftrace buffers, the "pid_maps" list of the copy can be initialized to NULL. -- Steve