Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753338Ab2EaFqW (ORCPT ); Thu, 31 May 2012 01:46:22 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:51948 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752446Ab2EaFqH (ORCPT ); Thu, 31 May 2012 01:46:07 -0400 X-AuditID: 9c930197-b7be2ae000000ebb-74-4fc7059a9b3c From: Namhyung Kim To: Arnaldo Carvalho de Melo Cc: Peter Zijlstra , Paul Mackerras , Ingo Molnar , Namhyung Kim , LKML , Sunjin Yang Subject: [PATCH/RFC 2/2] perf tools: Check callchain is corrupted Date: Thu, 31 May 2012 14:43:27 +0900 Message-Id: <1338443007-24857-2-git-send-email-namhyung.kim@lge.com> X-Mailer: git-send-email 1.7.10.2 In-Reply-To: <1338443007-24857-1-git-send-email-namhyung.kim@lge.com> References: <1338443007-24857-1-git-send-email-namhyung.kim@lge.com> X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2273 Lines: 74 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 --- 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 8adf70e9e3cc..0430ea6054ef 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 a7de2acac460..fa14e60ed459 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; } -- 1.7.10.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/