From: Kan Liang <[email protected]> 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 <[email protected]> Signed-off-by: Kan Liang <[email protected]> --- 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
