[tip:perf/core] perf tools: Fix perf script python database export crash

[tip-bot for Chris Phlipot]

Commit-ID:  616df645d7238e45d3b369933a30fee4e4e305e2
Gitweb:     http://git.kernel.org/tip/616df645d7238e45d3b369933a30fee4e4e305e2
Author:     Chris Phlipot <cphlipot0@xxxxxxxxx>
AuthorDate: Tue, 8 Mar 2016 21:11:54 -0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 9 Mar 2016 10:31:02 -0300

perf tools: Fix perf script python database export crash

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 efad78f..501ea6e 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;