Commit-ID: 114067b69e7b2c691faace0e33db2f04096f668d
Gitweb: http://git.kernel.org/tip/114067b69e7b2c691faace0e33db2f04096f668d
Author: Namhyung Kim <namhyung.kim@xxxxxxx>
AuthorDate: Thu, 31 May 2012 14:43:27 +0900
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 31 May 2012 11:20:34 -0300
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@xxxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung.kim@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Sunjin Yang <fan4326@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1338443007-24857-2-git-send-email-namhyung.kim@xxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
include/linux/perf_event.h | 4 ++--
tools/perf/util/session.c | 14 +++++++++++++-
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index f325786..1817d40 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];
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 3b6f8e4..04d1e33 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -300,6 +300,11 @@ int machine__resolve_callchain(struct machine *self,
callchain_cursor_reset(&callchain_cursor);
+ if (chain->nr > PERF_MAX_STACK_DEPTH) {
+ pr_warning("corrupted callchain. skipping...\n");
+ return 0;
+ }
+
for (i = 0; i < chain->nr; i++) {
u64 ip;
struct addr_location al;
@@ -318,7 +323,14 @@ int machine__resolve_callchain(struct machine *self,
case PERF_CONTEXT_USER:
cpumode = PERF_RECORD_MISC_USER; break;
default:
- break;
+ pr_debug("invalid callchain context: "
+ "%"PRId64"\n", (s64) ip);
+ /*
+ * It seems the callchain is corrupted.
+ * Discard all.
+ */
+ callchain_cursor_reset(&callchain_cursor);
+ return 0;
}
continue;
}
--
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