This is a note to let you know that I've just added the patch titled perf intel-pt: Fix snapshot overlap detection decoder errors to the 4.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: perf-intel-pt-fix-snapshot-overlap-detection-decoder-errors.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 810c398bc09b2f2dfde52a7d2483a710612c5fb8 Mon Sep 17 00:00:00 2001 From: Adrian Hunter <adrian.hunter@xxxxxxxxx> Date: Fri, 23 Sep 2016 17:38:41 +0300 Subject: perf intel-pt: Fix snapshot overlap detection decoder errors From: Adrian Hunter <adrian.hunter@xxxxxxxxx> 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 <adrian.hunter@xxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Link: http://lkml.kernel.org/r/1474641528-18776-10-git-send-email-adrian.hunter@xxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -241,7 +241,7 @@ 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) @@ -264,9 +264,6 @@ 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; @@ -276,6 +273,16 @@ 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; Patches currently in stable-queue which might be from adrian.hunter@xxxxxxxxx are queue-4.8/mmc-sdhci-cast-unsigned-int-to-unsigned-long-long-to-avoid-unexpeted-error.patch queue-4.8/perf-intel-pt-fix-estimated-timestamps-for-cycle-accurate-mode.patch queue-4.8/perf-intel-pt-fix-mtc-timestamp-calculation-for-large-mtc-periods.patch queue-4.8/perf-intel-pt-fix-snapshot-overlap-detection-decoder-errors.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html