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Groups > linux.kernel > #1621722

[PATCH 12/18] perf inject: Copy events when reordering events in pipe mode

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From: David Carrillo-Cisneros <davidcc@google.com>

__perf_session__process_pipe_events reuses the same memory buffer to
process all events in the pipe.

When reordering is needed (e.g. -b option), events are not immediately
flushed, but kept around until reordering is possible, causing
memory corruption.

The problem is usually observed by a "Unknown sample error" output. It
can easily be reproduced by:

  perf record -o - noploop | perf inject -b > output

Committer testing:

Before:

  $ perf record -o - stress -t 2 -c 2 | perf inject -b > /dev/null
  stress: info: [8297] dispatching hogs: 2 cpu, 0 io, 0 vm, 0 hdd
  stress: info: [8297] successful run completed in 2s
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB - ]
  Warning:
  Found 1 unknown events!

  Is this an older tool processing a perf.data file generated by a more recent tool?

  If that is not the case, consider reporting to linux-kernel@vger.kernel.org.

  $

After:

  $ perf record -o - stress -t 2 -c 2 | perf inject -b > /dev/null
  stress: info: [9027] dispatching hogs: 2 cpu, 0 io, 0 vm, 0 hdd
  stress: info: [9027] successful run completed in 2s
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB - ]
  no symbols found in /usr/bin/stress, maybe install a debug package?
  no symbols found in /usr/bin/stress, maybe install a debug package?
  $

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170410201432.24807-3-davidcc@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/ordered-events.c | 3 ++-
 tools/perf/util/session.c        | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/ordered-events.c b/tools/perf/util/ordered-events.c
index fe84df1875aa..e70e935b1841 100644
--- a/tools/perf/util/ordered-events.c
+++ b/tools/perf/util/ordered-events.c
@@ -79,7 +79,7 @@ static union perf_event *dup_event(struct ordered_events *oe,
 
 static void free_dup_event(struct ordered_events *oe, union perf_event *event)
 {
-	if (oe->copy_on_queue) {
+	if (event && oe->copy_on_queue) {
 		oe->cur_alloc_size -= event->header.size;
 		free(event);
 	}
@@ -150,6 +150,7 @@ void ordered_events__delete(struct ordered_events *oe, struct ordered_event *eve
 	list_move(&event->list, &oe->cache);
 	oe->nr_events--;
 	free_dup_event(oe, event->event);
+	event->event = NULL;
 }
 
 int ordered_events__queue(struct ordered_events *oe, union perf_event *event,
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 24259bc2c598..a25302bc55a8 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1656,6 +1656,7 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
 	buf = malloc(cur_size);
 	if (!buf)
 		return -errno;
+	ordered_events__set_copy_on_queue(oe, true);
 more:
 	event = buf;
 	err = readn(fd, event, sizeof(struct perf_event_header));
-- 
2.9.3

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[GIT PULL 00/18] perf/core improvements and fixes Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 09/18] perf annotate s390: Fix perf annotate error -95 (4.10 regression) Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 03/18] perf evsel: Return exact sub event which failed with EPERM for wildcards Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 14/18] perf annotate: Process attr and build_id records Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 16/18] perf tools: Do not print missing features in pipe-mode Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 07/18] perf tools: Refactor the code to strip command name with {l,r}trim() Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 12/18] perf inject: Copy events when reordering events in pipe mode Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 08/18] perf string: Simplify ltrim() implementation Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 01/18] perf callchains: Switch from strtok() to strtok_r() when parsing options Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 17/18] perf annotate: Refactor the code to parse disassemble lines with {l,r}trim() Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 10/18] perf annotate s390: Implement jump types for perf annotate Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 06/18] perf pmu: Refactor wordwrap() with ltrim() Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 13/18] perf tools: Describe pipe mode in perf.data-file-fomat.txt Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 15/18] perf session: Don't rely on evlist in pipe mode Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 18/18] perf annotate: Use stripped line instead of raw disassemble line Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 05/18] perf ui browser: Refactor the code to parse color configs with ltrim() Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  [PATCH 02/18] perf script: Use strtok_r() when parsing output field list Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-04-12 03:00 +0200
  Re: [GIT PULL 00/18] perf/core improvements and fixes Ingo Molnar <mingo@kernel.org> - 2017-04-12 07:40 +0200
    Re: [GIT PULL 00/18] perf/core improvements and fixes Christian Borntraeger <borntraeger@de.ibm.com> - 2017-04-12 09:20 +0200
      Re: [GIT PULL 00/18] perf/core improvements and fixes Ingo Molnar <mingo@kernel.org> - 2017-04-12 09:30 +0200

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