Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754985AbbFKPCg (ORCPT ); Thu, 11 Jun 2015 11:02:36 -0400 Received: from mga11.intel.com ([192.55.52.93]:22505 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754843AbbFKPCf (ORCPT ); Thu, 11 Jun 2015 11:02:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,595,1427785200"; d="scan'208";a="586082231" From: kan.liang@intel.com To: acme@kernel.org Cc: linux-kernel@vger.kernel.org, ying.huang@intel.com, andi@firstfloor.org, Kan Liang Subject: [PATCH V2 1/1] perf,tools: add time out to force stop endless mmap processing Date: Thu, 11 Jun 2015 03:49:04 -0400 Message-Id: <1434008944-10042-1-git-send-email-kan.liang@intel.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2042 Lines: 70 From: Kan Liang perf top reads all threads' /proc/xxx/maps. If there is any threads which generating a keeping growing huge /proc/xxx/maps, perf will do infinite loop in perf_event__synthesize_mmap_events. This patch fixes this issue by adding a time out to force stop this kind of endless mmap processing. Reported-by: Huang, Ying Signed-off-by: Kan Liang --- Changes since V1 - Add warning message for time out. tools/perf/util/event.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 793b150..b4dccf2 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -213,6 +213,8 @@ static int perf_event__synthesize_fork(struct perf_tool *tool, return 0; } +#define MMAP_TIMEOUT (50 * 1000000ULL) + int perf_event__synthesize_mmap_events(struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, @@ -222,6 +224,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, { char filename[PATH_MAX]; FILE *fp; + unsigned long long t; int rc = 0; if (machine__is_default_guest(machine)) @@ -240,6 +243,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, } event->header.type = PERF_RECORD_MMAP2; + t = rdclock(); while (1) { char bf[BUFSIZ]; @@ -253,6 +257,13 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, if (fgets(bf, sizeof(bf), fp) == NULL) break; + if ((rdclock() - t) > MMAP_TIMEOUT) { + pr_warning("Reading %s time out." + "The file may be too huge or keep growing.\n", + filename); + break; + } + /* ensure null termination since stack will be reused. */ strcpy(execname, ""); -- 1.8.3.1 -- 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/