From 930e6fcd2bcce9bcd9d4aa7e755678d33f3fe6f4 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Wed, 17 Jun 2015 09:51:10 -0400 Subject: perf tools: Add time out to force stop proc map processing System wide sampling like 'perf top' or 'perf record -a' read all threads /proc/xxx/maps before sampling. If there are any threads which generating a keeping growing huge maps, perf will do infinite loop during synthesizing. Nothing will be sampled. This patch fixes this issue by adding per-thread timeout to force stop this kind of endless proc map processing. PERF_RECORD_MISC_PROC_MAP_PARSE_TIME_OUT is introduced to indicate that the mmap record are truncated by time out. User will get warning notification when truncated mmap records are detected. Reported-by: Ying Huang Signed-off-by: Kan Liang Cc: Andi Kleen Cc: David Ahern Cc: Ying Huang Link: http://lkml.kernel.org/r/1434549071-25611-1-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/event.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'tools/perf/util/event.c') diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 793b1503d437..416ba80c628f 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 PROC_MAP_PARSE_TIMEOUT (500 * 1000000ULL) + int perf_event__synthesize_mmap_events(struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, @@ -222,6 +224,8 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, { char filename[PATH_MAX]; FILE *fp; + unsigned long long t; + bool truncation = false; int rc = 0; if (machine__is_default_guest(machine)) @@ -240,6 +244,7 @@ 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 +258,12 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, if (fgets(bf, sizeof(bf), fp) == NULL) break; + if ((rdclock() - t) > PROC_MAP_PARSE_TIMEOUT) { + pr_warning("Reading %s time out.\n", filename); + truncation = true; + goto out; + } + /* ensure null termination since stack will be reused. */ strcpy(execname, ""); @@ -301,6 +312,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, event->header.misc |= PERF_RECORD_MISC_MMAP_DATA; } +out: + if (truncation) + event->header.misc |= PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT; + if (!strcmp(execname, "")) strcpy(execname, anonstr); @@ -319,6 +334,9 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, rc = -1; break; } + + if (truncation) + break; } fclose(fp); -- cgit v1.2.1