[tip:perf/urgent] perf machine: Add missing dsos-> root rbtree root initialization

From: tip-bot for Arnaldo Carvalho de Melo
Date: Wed Oct 15 2014 - 06:06:30 EST

Commit-ID: e167f995e26249aa93708589c5eea539652351fa
Gitweb: http://git.kernel.org/tip/e167f995e26249aa93708589c5eea539652351fa
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 14 Oct 2014 15:07:48 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 14 Oct 2014 17:50:44 -0300

perf machine: Add missing dsos->root rbtree root initialization

A segfault happens on 'perf test hists_link' because we end up using a
struct machines on the stack, and then machines__init() was not
initializing the newly introduced rb_root, just the existing list_head.

When we introduced struct dsos, to group the two ways to store dsos,
i.e. the linked list and the rbtree, we didn't turned the initialization
done in:

machines__init(machines->host) ->
machine__init() ->

into a dsos__init() to keep on initializing the list_head but _as well_
initializing the rb_root, oops.

All worked because outside perf-test we probably zalloc the whole thing
which ends up initializing it in to NULL.

So the problem looks contained to 'perf test' that uses it on stack,

Reported-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Acked-by: Waiman Long <Waiman.Long@xxxxxx>,
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>,
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Douglas Hatch <doug.hatch@xxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Scott J Norton <scott.norton@xxxxxx>
Cc: Waiman Long <Waiman.Long@xxxxxx>,
Link: http://lkml.kernel.org/r/20141014180353.GF3198@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/util/machine.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index b7d477f..34fc7c8 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -13,12 +13,18 @@
#include <symbol/kallsyms.h>
#include "unwind.h"

+static void dsos__init(struct dsos *dsos)
+ INIT_LIST_HEAD(&dsos->head);
+ dsos->root = RB_ROOT;
int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
- INIT_LIST_HEAD(&machine->user_dsos.head);
- INIT_LIST_HEAD(&machine->kernel_dsos.head);
+ dsos__init(&machine->user_dsos);
+ dsos__init(&machine->kernel_dsos);

machine->threads = RB_ROOT;
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