perf tools: Check if callchain is corrupted

We faced segmentation fault on perf top -G at very high sampling rate
due to a corrupted callchain. While the root cause was not revealed (I
failed to figure it out), this patch tries to protect us from the
segfault on such cases.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sunjin Yang <fan4326@gmail.com>
Link: http://lkml.kernel.org/r/1338443007-24857-2-git-send-email-namhyung.kim@lge.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index f32578634d9d..1817d4015e5f 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -555,6 +555,8 @@ enum perf_event_type {
         PERF_RECORD_MAX,                        /* non-ABI */
 };
 
+#define PERF_MAX_STACK_DEPTH            255
+
 enum perf_callchain_context {
         PERF_CONTEXT_HV                 = (__u64)-32,
         PERF_CONTEXT_KERNEL             = (__u64)-128,
@@ -609,8 +611,6 @@ struct perf_guest_info_callbacks {
 #include <linux/sysfs.h>
 #include <asm/local.h>
 
-#define PERF_MAX_STACK_DEPTH            255
-
 struct perf_callchain_entry {
         __u64                           nr;
         __u64                           ip[PERF_MAX_STACK_DEPTH];