This is a note to let you know that I've just added the patch titled
perf tools: Handle old data in PERF_RECORD_ATTR
to the 6.1-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-tools-handle-old-data-in-perf_record_attr.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9bf63282ea77a531ea58acb42fb3f40d2d1e4497 Mon Sep 17 00:00:00 2001
From: Namhyung Kim <namhyung@xxxxxxxxxx>
Date: Fri, 25 Aug 2023 08:25:49 -0700
Subject: perf tools: Handle old data in PERF_RECORD_ATTR
From: Namhyung Kim <namhyung@xxxxxxxxxx>
commit 9bf63282ea77a531ea58acb42fb3f40d2d1e4497 upstream.
The PERF_RECORD_ATTR is used for a pipe mode to describe an event with
attribute and IDs. The ID table comes after the attr and it calculate
size of the table using the total record size and the attr size.
n_ids = (total_record_size - end_of_the_attr_field) / sizeof(u64)
This is fine for most use cases, but sometimes it saves the pipe output
in a file and then process it later. And it becomes a problem if there
is a change in attr size between the record and report.
$ perf record -o- > perf-pipe.data # old version
$ perf report -i- < perf-pipe.data # new version
For example, if the attr size is 128 and it has 4 IDs, then it would
save them in 168 byte like below:
8 byte: perf event header { .type = PERF_RECORD_ATTR, .size = 168 },
128 byte: perf event attr { .size = 128, ... },
32 byte: event IDs [] = { 1234, 1235, 1236, 1237 },
But when report later, it thinks the attr size is 136 then it only read
the last 3 entries as ID.
8 byte: perf event header { .type = PERF_RECORD_ATTR, .size = 168 },
136 byte: perf event attr { .size = 136, ... },
24 byte: event IDs [] = { 1235, 1236, 1237 }, // 1234 is missing
So it should use the recorded version of the attr. The attr has the
size field already then it should honor the size when reading data.
Fixes: 2c46dbb517a10b18 ("perf: Convert perf header attrs into attr events")
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Tom Zanussi <zanussi@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230825152552.112913-1-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/util/header.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -4331,7 +4331,8 @@ int perf_event__process_attr(struct perf
union perf_event *event,
struct evlist **pevlist)
{
- u32 i, ids, n_ids;
+ u32 i, n_ids;
+ u64 *ids;
struct evsel *evsel;
struct evlist *evlist = *pevlist;
@@ -4347,9 +4348,8 @@ int perf_event__process_attr(struct perf
evlist__add(evlist, evsel);
- ids = event->header.size;
- ids -= (void *)&event->attr.id - (void *)event;
- n_ids = ids / sizeof(u64);
+ n_ids = event->header.size - sizeof(event->header) - event->attr.attr.size;
+ n_ids = n_ids / sizeof(u64);
/*
* We don't have the cpu and thread maps on the header, so
* for allocating the perf_sample_id table we fake 1 cpu and
@@ -4358,8 +4358,9 @@ int perf_event__process_attr(struct perf
if (perf_evsel__alloc_id(&evsel->core, 1, n_ids))
return -ENOMEM;
+ ids = (void *)&event->attr.attr + event->attr.attr.size;
for (i = 0; i < n_ids; i++) {
- perf_evlist__id_add(&evlist->core, &evsel->core, 0, i, event->attr.id[i]);
+ perf_evlist__id_add(&evlist->core, &evsel->core, 0, i, ids[i]);
}
return 0;
Patches currently in stable-queue which might be from namhyung@xxxxxxxxxx are
queue-6.1/perf-hists-browser-fix-the-number-of-entries-for-e-key.patch
queue-6.1/perf-test-stat_bpf_counters_cgrp-fix-shellcheck-issu.patch
queue-6.1/perf-tools-handle-old-data-in-perf_record_attr.patch
queue-6.1/perf-test-stat_bpf_counters_cgrp-enhance-perf-stat-c.patch
queue-6.1/perf-hists-browser-fix-hierarchy-mode-header.patch
queue-6.1/perf-build-update-build-rule-for-generated-files.patch
queue-6.1/perf-top-don-t-pass-an-err_ptr-directly-to-perf_sess.patch
queue-6.1/perf-annotate-bpf-don-t-enclose-non-debug-code-with-.patch
queue-6.1/perf-trace-really-free-the-evsel-priv-area.patch
queue-6.1/perf-test-shell-stat_bpf_counters-fix-test-on-intel.patch
queue-6.1/perf-vendor-events-drop-stores_per_inst-metric-event.patch
queue-6.1/perf-vendor-events-drop-some-of-the-json-events-for-.patch
queue-6.1/perf-vendor-events-update-the-json-events-descriptio.patch
