Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030213AbcJZMyo (ORCPT ); Wed, 26 Oct 2016 08:54:44 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55900 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966792AbcJZMdp (ORCPT ); Wed, 26 Oct 2016 08:33:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Adrian Hunter , Jiri Olsa , Masami Hiramatsu , Mathieu Poirier , Arnaldo Carvalho de Melo Subject: [PATCH 4.4 019/112] perf intel-pt: Fix snapshot overlap detection decoder errors Date: Wed, 26 Oct 2016 14:22:02 +0200 Message-Id: <20161026122305.602302057@linuxfoundation.org> X-Mailer: git-send-email 2.10.1 In-Reply-To: <20161026122304.797016625@linuxfoundation.org> References: <20161026122304.797016625@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2302 Lines: 70 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Adrian Hunter commit 810c398bc09b2f2dfde52a7d2483a710612c5fb8 upstream. Fix occasional decoder errors decoding trace data collected in snapshot mode. Snapshot mode can take successive snapshots of trace which might overlap. The decoder checks whether there is an overlap but only looks at the current and previous buffer. However buffers that do not contain synchronization (i.e. PSB) packets cannot be decoded or used for overlap checking. That means the decoder actually needs to check overlaps between the current buffer and the previous buffer that contained usable data. Make that change. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Mathieu Poirier Link: http://lkml.kernel.org/r/1474641528-18776-10-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman --- tools/perf/util/intel-pt.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) --- a/tools/perf/util/intel-pt.c +++ b/tools/perf/util/intel-pt.c @@ -238,7 +238,7 @@ static int intel_pt_get_trace(struct int } queue = &ptq->pt->queues.queue_array[ptq->queue_nr]; - +next: buffer = auxtrace_buffer__next(queue, buffer); if (!buffer) { if (old_buffer) @@ -261,9 +261,6 @@ static int intel_pt_get_trace(struct int intel_pt_do_fix_overlap(ptq->pt, old_buffer, buffer)) return -ENOMEM; - if (old_buffer) - auxtrace_buffer__drop_data(old_buffer); - if (buffer->use_data) { b->len = buffer->use_size; b->buf = buffer->use_data; @@ -273,6 +270,16 @@ static int intel_pt_get_trace(struct int } b->ref_timestamp = buffer->reference; + /* + * If in snapshot mode and the buffer has no usable data, get next + * buffer and again check overlap against old_buffer. + */ + if (ptq->pt->snapshot_mode && !b->len) + goto next; + + if (old_buffer) + auxtrace_buffer__drop_data(old_buffer); + if (!old_buffer || ptq->pt->sampling_mode || (ptq->pt->snapshot_mode && !buffer->consecutive)) { b->consecutive = false;