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perf record: Fix crash in pipe mode

PATCH In review Jiri Olsa 3 participants 4 messages Mar 2, 2018 – Mar 7, 2018 perf events

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Jiri Olsa

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#0 lore raw

PATCH 1/1 perf record: Fix crash in pipe mode

Currently we can crash perf record when running in pipe mode, like:

  $ perf record ls | perf report
  # To display the perf.data header info, please use --header/--header-only options.
  #
  perf: Segmentation fault
  Error:
  The - file has no samples!

The callstack of the crash is:

    0x0000000000515242 in perf_event__synthesize_event_update_name
  3513            ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
  (gdb) bt
  #0  0x0000000000515242 in perf_event__synthesize_event_update_name
  #1  0x00000000005158a4 in perf_event__synthesize_extra_attr
  #2  0x0000000000443347 in record__synthesize
  #3  0x00000000004438e3 in __cmd_record
  #4  0x000000000044514e in cmd_record
  #5  0x00000000004cbc95 in run_builtin
  #6  0x00000000004cbf02 in handle_internal_command
  #7  0x00000000004cc054 in run_argv
  #8  0x00000000004cc422 in main

The reason of the crash is that the evsel does not have ids array allocated and the pipe's synthesize code tries to access it.

We don't force evsel ids allocation when we have single event, because it's not needed. However we need it when we are in pipe mode even for single event as a key for evsel update event.

Fixing this by forcing evsel ids allocation event for single event, when we are in pipe mode.

---
 tools/perf/builtin-record.c | 9 +++++++++
 tools/perf/perf.h           | 1 +
 tools/perf/util/record.c    | 8 ++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)
tools/perf/builtin-record.c +9 -0
index a60f398cbc24..eeef1143bae3 100644
@@ -881,6 +881,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		}
 	}
 
+	/*
+	 * If we have just single event and are sending data
+	 * through pipe, we need to force the ids allocation,
+	 * because we synthesize event name through the pipe
+	 * and need the id for that.
+	 */
+	if (data->is_pipe && rec->evlist->nr_entries == 1)
+		rec->opts.sample_id = true;
+
 	if (record__open(rec) != 0) {
 		err = -1;
 		goto out_child;
tools/perf/perf.h +1 -0
index 007e0dfd5ce3..8fec1abd0f1f 100644
@@ -62,6 +62,7 @@ struct record_opts {
 	bool	     overwrite;
 	bool	     ignore_missing_thread;
 	bool	     strict_freq;
+	bool	     sample_id;
 	unsigned int freq;
 	unsigned int mmap_pages;
 	unsigned int auxtrace_mmap_pages;
tools/perf/util/record.c +6 -2
index 3878c503f464..867f5937ebb7 100644
@@ -138,6 +138,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 	struct perf_evsel *evsel;
 	bool use_sample_identifier = false;
 	bool use_comm_exec;
+	bool sample_id = opts->sample_id;
 
 	/*
 	 * Set the evsel leader links before we configure attributes,
@@ -164,8 +165,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 		 * match the id.
 		 */
 		use_sample_identifier = perf_can_sample_identifier();
-		evlist__for_each_entry(evlist, evsel)
-			perf_evsel__set_sample_id(evsel, use_sample_identifier);
+		sample_id = true;
 	} else if (evlist->nr_entries > 1) {
 		struct perf_evsel *first = perf_evlist__first(evlist);
 
@@ -175,6 +175,10 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 			use_sample_identifier = perf_can_sample_identifier();
 			break;
 		}
+		sample_id = true;
+	}
+
+	if (sample_id) {
 		evlist__for_each_entry(evlist, evsel)
 			perf_evsel__set_sample_id(evsel, use_sample_identifier);
 	}
Signature · 1 line
2.13.6
#1 lore raw

Em Fri, Mar 02, 2018 at 05:13:54PM +0100, Jiri Olsa escreveu:

Quoted 10 lines

Currently we can crash perf record when running in pipe mode, like:

  $ perf record ls | perf report
  # To display the perf.data header info, please use --header/--header-only options.
  #
  perf: Segmentation fault
  Error:
  The - file has no samples!

The callstack of the crash is:

Thanks, reproduced the problem, applied the patch, tested, fixed, simple enough, applied.

- Arnaldo

Quoted 98 lines
    0x0000000000515242 in perf_event__synthesize_event_update_name
  3513            ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
  (gdb) bt
  #0  0x0000000000515242 in perf_event__synthesize_event_update_name
  #1  0x00000000005158a4 in perf_event__synthesize_extra_attr
  #2  0x0000000000443347 in record__synthesize
  #3  0x00000000004438e3 in __cmd_record
  #4  0x000000000044514e in cmd_record
  #5  0x00000000004cbc95 in run_builtin
  #6  0x00000000004cbf02 in handle_internal_command
  #7  0x00000000004cc054 in run_argv
  #8  0x00000000004cc422 in main

The reason of the crash is that the evsel does not have ids array allocated and the pipe's synthesize code tries to access it.

We don't force evsel ids allocation when we have single event, because it's not needed. However we need it when we are in pipe mode even for single event as a key for evsel update event.

Fixing this by forcing evsel ids allocation event for single event, when we are in pipe mode.

---
 tools/perf/builtin-record.c | 9 +++++++++
 tools/perf/perf.h           | 1 +
 tools/perf/util/record.c    | 8 ++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)
tools/perf/builtin-record.c +9 -0
index a60f398cbc24..eeef1143bae3 100644
@@ -881,6 +881,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		}
 	}
 
+	/*
+	 * If we have just single event and are sending data
+	 * through pipe, we need to force the ids allocation,
+	 * because we synthesize event name through the pipe
+	 * and need the id for that.
+	 */
+	if (data->is_pipe && rec->evlist->nr_entries == 1)
+		rec->opts.sample_id = true;
+
 	if (record__open(rec) != 0) {
 		err = -1;
 		goto out_child;
tools/perf/perf.h +1 -0
index 007e0dfd5ce3..8fec1abd0f1f 100644
@@ -62,6 +62,7 @@ struct record_opts {
 	bool	     overwrite;
 	bool	     ignore_missing_thread;
 	bool	     strict_freq;
+	bool	     sample_id;
 	unsigned int freq;
 	unsigned int mmap_pages;
 	unsigned int auxtrace_mmap_pages;
tools/perf/util/record.c +6 -2
index 3878c503f464..867f5937ebb7 100644
@@ -138,6 +138,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 	struct perf_evsel *evsel;
 	bool use_sample_identifier = false;
 	bool use_comm_exec;
+	bool sample_id = opts->sample_id;
 
 	/*
 	 * Set the evsel leader links before we configure attributes,
@@ -164,8 +165,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 		 * match the id.
 		 */
 		use_sample_identifier = perf_can_sample_identifier();
-		evlist__for_each_entry(evlist, evsel)
-			perf_evsel__set_sample_id(evsel, use_sample_identifier);
+		sample_id = true;
 	} else if (evlist->nr_entries > 1) {
 		struct perf_evsel *first = perf_evlist__first(evlist);
 
@@ -175,6 +175,10 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 			use_sample_identifier = perf_can_sample_identifier();
 			break;
 		}
+		sample_id = true;
+	}
+
+	if (sample_id) {
 		evlist__for_each_entry(evlist, evsel)
 			perf_evsel__set_sample_id(evsel, use_sample_identifier);
 	}
Signature · 1 line
2.13.6
#2 lore raw
In reply to Jiri Olsa
perf record: Fix crash in pipe mode
Commit-ID:  ad46e48c65fa1f204fa29eaff1b91174d314a94b
Gitweb:     https://git.kernel.org/tip/ad46e48c65fa1f204fa29eaff1b91174d314a94b
Author:     Jiri Olsa <[email protected]>
AuthorDate: Fri, 2 Mar 2018 17:13:54 +0100
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Mon, 5 Mar 2018 09:58:45 -0300

perf record: Fix crash in pipe mode

Currently we can crash perf record when running in pipe mode, like:

  $ perf record ls | perf report
  # To display the perf.data header info, please use --header/--header-only options.
  #
  perf: Segmentation fault
  Error:
  The - file has no samples!

The callstack of the crash is:

    0x0000000000515242 in perf_event__synthesize_event_update_name
  3513            ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
  (gdb) bt
  #0  0x0000000000515242 in perf_event__synthesize_event_update_name
  #1  0x00000000005158a4 in perf_event__synthesize_extra_attr
  #2  0x0000000000443347 in record__synthesize
  #3  0x00000000004438e3 in __cmd_record
  #4  0x000000000044514e in cmd_record
  #5  0x00000000004cbc95 in run_builtin
  #6  0x00000000004cbf02 in handle_internal_command
  #7  0x00000000004cc054 in run_argv
  #8  0x00000000004cc422 in main

The reason of the crash is that the evsel does not have ids array allocated and the pipe's synthesize code tries to access it.

We don't force evsel ids allocation when we have single event, because it's not needed. However we need it when we are in pipe mode even for single event as a key for evsel update event.

Fixing this by forcing evsel ids allocation event for single event, when we are in pipe mode.

---
 tools/perf/builtin-record.c | 9 +++++++++
 tools/perf/perf.h           | 1 +
 tools/perf/util/record.c    | 8 ++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)
tools/perf/builtin-record.c +9 -0
index 62387942a1d5..12230ddb6506 100644
@@ -882,6 +882,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		}
 	}
 
+	/*
+	 * If we have just single event and are sending data
+	 * through pipe, we need to force the ids allocation,
+	 * because we synthesize event name through the pipe
+	 * and need the id for that.
+	 */
+	if (data->is_pipe && rec->evlist->nr_entries == 1)
+		rec->opts.sample_id = true;
+
 	if (record__open(rec) != 0) {
 		err = -1;
 		goto out_child;
tools/perf/perf.h +1 -0
index 007e0dfd5ce3..8fec1abd0f1f 100644
@@ -62,6 +62,7 @@ struct record_opts {
 	bool	     overwrite;
 	bool	     ignore_missing_thread;
 	bool	     strict_freq;
+	bool	     sample_id;
 	unsigned int freq;
 	unsigned int mmap_pages;
 	unsigned int auxtrace_mmap_pages;
tools/perf/util/record.c +6 -2
index 4f1a82e76d39..9cfc7bf16531 100644
@@ -138,6 +138,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 	struct perf_evsel *evsel;
 	bool use_sample_identifier = false;
 	bool use_comm_exec;
+	bool sample_id = opts->sample_id;
 
 	/*
 	 * Set the evsel leader links before we configure attributes,
@@ -164,8 +165,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 		 * match the id.
 		 */
 		use_sample_identifier = perf_can_sample_identifier();
-		evlist__for_each_entry(evlist, evsel)
-			perf_evsel__set_sample_id(evsel, use_sample_identifier);
+		sample_id = true;
 	} else if (evlist->nr_entries > 1) {
 		struct perf_evsel *first = perf_evlist__first(evlist);
 
@@ -175,6 +175,10 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 			use_sample_identifier = perf_can_sample_identifier();
 			break;
 		}
+		sample_id = true;
+	}
+
+	if (sample_id) {
 		evlist__for_each_entry(evlist, evsel)
 			perf_evsel__set_sample_id(evsel, use_sample_identifier);
 	}
#3 lore raw
In reply to Jiri Olsa
perf record: Fix crash in pipe mode
Commit-ID:  cfacbabd1d9c35d2a179650b2911f17a8d8620b8
Gitweb:     https://git.kernel.org/tip/cfacbabd1d9c35d2a179650b2911f17a8d8620b8
Author:     Jiri Olsa <[email protected]>
AuthorDate: Fri, 2 Mar 2018 17:13:54 +0100
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Mon, 5 Mar 2018 11:52:41 -0300

perf record: Fix crash in pipe mode

Currently we can crash perf record when running in pipe mode, like:

  $ perf record ls | perf report
  # To display the perf.data header info, please use --header/--header-only options.
  #
  perf: Segmentation fault
  Error:
  The - file has no samples!

The callstack of the crash is:

    0x0000000000515242 in perf_event__synthesize_event_update_name
  3513            ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
  (gdb) bt
  #0  0x0000000000515242 in perf_event__synthesize_event_update_name
  #1  0x00000000005158a4 in perf_event__synthesize_extra_attr
  #2  0x0000000000443347 in record__synthesize
  #3  0x00000000004438e3 in __cmd_record
  #4  0x000000000044514e in cmd_record
  #5  0x00000000004cbc95 in run_builtin
  #6  0x00000000004cbf02 in handle_internal_command
  #7  0x00000000004cc054 in run_argv
  #8  0x00000000004cc422 in main

The reason of the crash is that the evsel does not have ids array allocated and the pipe's synthesize code tries to access it.

We don't force evsel ids allocation when we have single event, because it's not needed. However we need it when we are in pipe mode even for single event as a key for evsel update event.

Fixing this by forcing evsel ids allocation event for single event, when we are in pipe mode.

---
 tools/perf/builtin-record.c | 9 +++++++++
 tools/perf/perf.h           | 1 +
 tools/perf/util/record.c    | 8 ++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)
tools/perf/builtin-record.c +9 -0
index bf4ca749d1ac..a217623fec2e 100644
@@ -881,6 +881,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		}
 	}
 
+	/*
+	 * If we have just single event and are sending data
+	 * through pipe, we need to force the ids allocation,
+	 * because we synthesize event name through the pipe
+	 * and need the id for that.
+	 */
+	if (data->is_pipe && rec->evlist->nr_entries == 1)
+		rec->opts.sample_id = true;
+
 	if (record__open(rec) != 0) {
 		err = -1;
 		goto out_child;
tools/perf/perf.h +1 -0
index cfe46236a5e5..57b9b342d533 100644
@@ -61,6 +61,7 @@ struct record_opts {
 	bool	     tail_synthesize;
 	bool	     overwrite;
 	bool	     ignore_missing_thread;
+	bool	     sample_id;
 	unsigned int freq;
 	unsigned int mmap_pages;
 	unsigned int auxtrace_mmap_pages;
tools/perf/util/record.c +6 -2
index 1e97937b03a9..6f09e4962dad 100644
@@ -137,6 +137,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 	struct perf_evsel *evsel;
 	bool use_sample_identifier = false;
 	bool use_comm_exec;
+	bool sample_id = opts->sample_id;
 
 	/*
 	 * Set the evsel leader links before we configure attributes,
@@ -163,8 +164,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 		 * match the id.
 		 */
 		use_sample_identifier = perf_can_sample_identifier();
-		evlist__for_each_entry(evlist, evsel)
-			perf_evsel__set_sample_id(evsel, use_sample_identifier);
+		sample_id = true;
 	} else if (evlist->nr_entries > 1) {
 		struct perf_evsel *first = perf_evlist__first(evlist);
 
@@ -174,6 +174,10 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
 			use_sample_identifier = perf_can_sample_identifier();
 			break;
 		}
+		sample_id = true;
+	}
+
+	if (sample_id) {
 		evlist__for_each_entry(evlist, evsel)
 			perf_evsel__set_sample_id(evsel, use_sample_identifier);
 	}