From 114067b69e7b2c691faace0e33db2f04096f668d Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Thu, 31 May 2012 14:43:27 +0900 Subject: 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 Signed-off-by: Namhyung Kim Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Sunjin Yang Link: http://lkml.kernel.org/r/1338443007-24857-2-git-send-email-namhyung.kim@lge.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 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 #include -#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 3b6f8e460a31..04d1e33f4592 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; } -- cgit v1.2.1