Subject: [PATCH 4.18 054/350] perf evsel: Store ids for events with their own cpus perf_event__synthesize_event_update_cpus

From: [email-masked] (Greg Kroah-Hartman)
Date: Sun, 11 Nov 2018 14:18:38 -0800

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Olsa <[email-masked]>

[ Upstream commit 4ab8455f8bd83298bf7f67ab9357e3b1cc765c7d ]

John reported crash when recording on an event under PMU with cpumask defined:

  root at localhost:~# ./perf_debug_ record -e armv8_pmuv3_0/br_mis_pred/ sleep 1
  perf: Segmentation fault
  Obtained 9 stack frames.
  ./perf_debug_() [0x4c5ef8]
  [0xffff82ba267c]
  ./perf_debug_() [0x4bc5a8]
  ./perf_debug_() [0x419550]
  ./perf_debug_() [0x41a928]
  ./perf_debug_() [0x472f58]
  ./perf_debug_() [0x473210]
  ./perf_debug_() [0x4070f4]
  /lib/aarch64-linux-gnu/libc.so.6(__libc_start_main+0xe0) [0xffff8294c8a0]
  Segmentation fault (core dumped)

We synthesize an update event that needs to touch the evsel id array, which is
not defined at that time. Fixing this by forcing the id allocation for events
with their own cpus.

Reported-by: John Garry <[email-masked]>
Signed-off-by: Jiri Olsa <[email-masked]>
Tested-by: John Garry <[email-masked]>
Cc: Alexander Shishkin <[email-masked]>
Cc: Andi Kleen <[email-masked]>
Cc: Mark Rutland <[email-masked]>
Cc: Namhyung Kim <[email-masked]>
Cc: Peter Zijlstra <[email-masked]>
Cc: Will Deacon <[email-masked]>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linuxarm at huawei.com
Fixes: bfd8f72c2778 ("perf record: Synthesize unit/scale/... in event update")
Link: http://lkml.kernel.org/r/20181003212052.GA32371 at krava
Signed-off-by: Arnaldo Carvalho de Melo <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>
---
 tools/perf/builtin-report.c |    1 +
 tools/perf/util/evsel.c     |    3 +++
 2 files changed, 4 insertions(+)

--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -981,6 +981,7 @@ int cmd_report(int argc, const char **ar
 			.id_index	 = perf_event__process_id_index,
 			.auxtrace_info	 = perf_event__process_auxtrace_info,
 			.auxtrace	 = perf_event__process_auxtrace,
+			.event_update	 = perf_event__process_event_update,
 			.feature	 = process_feature_event,
 			.ordered_events	 = true,
 			.ordering_requires_timestamps = true,
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1078,6 +1078,9 @@ void perf_evsel__config(struct perf_evse
 		attr->exclude_user   = 1;
 	}
 
+	if (evsel->own_cpus)
+		evsel->attr.read_format |= PERF_FORMAT_ID;
+
 	/*
 	 * Apply event specific term settings,
 	 * it overloads any global configuration.