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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>
This commit is contained in:
Namhyung Kim 2012-05-31 14:43:27 +09:00 committed by Arnaldo Carvalho de Melo
parent 472606458f
commit 114067b69e
2 changed files with 15 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/perf_event.h
View File

@ -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];

14
tools/perf/util/session.c
View File

@ -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;
}