[PATCH 04/10] perf report: Fix a bug on "--call-graph none" option

From	Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups	linux.kernel
Subject	[PATCH 04/10] perf report: Fix a bug on "--call-graph none" option
Date	2015-10-02 22:30 +0200
Message-ID	<qff7P-5Cf-7@gated-at.bofh.it> (permalink)
References	<qff7P-5Cf-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Namhyung Kim <namhyung@kernel.org>

The patch f9db0d0f1b2c ("perf callchain: Allow disabling call graphs
per event") added an ability to enable/disable callchain recording per
event.  But it had a problem when the enablement setting is changed at
'perf report' time using -g/--call-graph option.

For example, the following scenario will get a segfault.

  $ perf record -ag sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.500 MB perf.data (2555 samples) ]

  $ perf report -g none
  perf: Segmentation fault
  -------- backtrace --------
  perf[0x53a98a]
  /usr/lib/libc.so.6(+0x335af)[0x7f4e91df95af]

This is because callchain_param.sort() callback was not set but it
tried to call the function as it had the PERF_SAMPLE_CALLCHAIN bit.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Fixes: f9db0d0f1b2c ("perf callchain: Allow disabling call graphs per event")
Link: http://lkml.kernel.org/r/1443587640-24242-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/hist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 0cad9e07c5b4..c346b331b892 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -1151,7 +1151,7 @@ void hists__output_resort(struct hists *hists, struct ui_progress *prog)
 	struct perf_evsel *evsel = hists_to_evsel(hists);
 	bool use_callchain;
 
-	if (evsel && !symbol_conf.show_ref_callgraph)
+	if (evsel && symbol_conf.use_callchain && !symbol_conf.show_ref_callgraph)
 		use_callchain = evsel->attr.sample_type & PERF_SAMPLE_CALLCHAIN;
 	else
 		use_callchain = symbol_conf.use_callchain;
-- 
2.1.0

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[PATCH 04/10] perf report: Fix a bug on "--call-graph none" option Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-02 22:30 +0200

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