[PATCH 02/19] perf tools: Fix perf script python database export crash

From: Arnaldo Carvalho de Melo
Date: Thu Mar 10 2016 - 16:05:01 EST

From: Chris Phlipot <cphlipot0@xxxxxxxxx>

Remove the union in evsel so that the database id and priv pointer can
be used simultainously without conflicting and crashing.

Detailed Description for the fixed bug follows:

perf script crashes with a segmentation fault on user space tool version
4.5.rc7.ge2857b when using the python database export API. It works
properly in 4.4 and prior versions.

the crash fist appeared in:

cfc8874a4859 ("perf script: Process cpu/threads maps")

How to reproduce the bug:

Remove any temporary files left over from a previous crash (if you have
already attemped to reproduce the bug):

$ rm -r test_db-perf-data
$ dropdb test_db

$ perf record timeout 1 yes >/dev/null
$ perf script -s scripts/python/export-to-postgresql.py test_db

Stack Trace:
Program received signal SIGSEGV, Segmentation fault.
__GI___libc_free (mem=0x1) at malloc.c:2929
2929 malloc.c: No such file or directory.
(gdb) bt
at util/stat.c:122
argv=<optimized out>, prefix=<optimized out>) at builtin-script.c:2231
argc=argc@entry=4, argv=argv@entry=0x7fffffffdf70) at perf.c:390
at perf.c:451

Signed-off-by: Chris Phlipot <cphlipot0@xxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Fixes: cfc8874a4859 ("perf script: Process cpu/threads maps")
Link: http://lkml.kernel.org/r/1457500314-8912-1-git-send-email-cphlipot0@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/util/evsel.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index efad78f811ad..501ea6e565f1 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -93,10 +93,8 @@ struct perf_evsel {
const char *unit;
struct event_format *tp_format;
off_t id_offset;
- union {
- void *priv;
- u64 db_id;
- };
+ void *priv;
+ u64 db_id;
struct cgroup_sel *cgrp;
void *handler;
struct cpu_map *cpus;