[tip:perf/core] perf stat: Fix saved values rbtree lookup

[tip-bot for Andi Kleen]

Commit-ID:  5e97665f91d343b5bcf1f92249e45e18987ffd00
Gitweb:     http://git.kernel.org/tip/5e97665f91d343b5bcf1f92249e45e18987ffd00
Author:     Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 24 Jul 2017 16:40:03 -0700
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 11 Aug 2017 10:42:52 -0300

perf stat: Fix saved values rbtree lookup

The stat shadow saved values rbtree is indexed by a pointer.  Fix the
comparison function:

- We cannot return a pointer delta as an int because that loses bits on
  64bit.

- Doing pointer arithmetic on the struct pointer only works if the
  objects are spaced by the multiple of the object size, which is not
  guaranteed for individual malloc'ed object

Replace it with a proper comparison.

This fixes various problems with values not being found.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170724234015.5165-4-andi@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/stat-shadow.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 719d6cb..a04cf56 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -70,7 +70,11 @@ static int saved_value_cmp(struct rb_node *rb_node, const void *entry)
 		return a->ctx - b->ctx;
 	if (a->cpu != b->cpu)
 		return a->cpu - b->cpu;
-	return a->evsel - b->evsel;
+	if (a->evsel == b->evsel)
+		return 0;
+	if ((char *)a->evsel < (char *)b->evsel)
+		return -1;
+	return +1;
 }
 
 static struct rb_node *saved_value_new(struct rblist *rblist __maybe_unused,