diff options
| -rw-r--r-- | src/shared/calendarspec.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/src/shared/calendarspec.c b/src/shared/calendarspec.c index db6a103c42..d83e0fbded 100644 --- a/src/shared/calendarspec.c +++ b/src/shared/calendarspec.c @@ -1211,6 +1211,10 @@ static bool matches_weekday(int weekdays_bits, const struct tm *tm, bool utc) { return (weekdays_bits & (1 << k)); } +/* A safety valve: if we get stuck in the calculation, return an error. + * C.f. https://bugzilla.redhat.com/show_bug.cgi?id=1941335. */ +#define MAX_CALENDAR_ITERATIONS 1000 + static int find_next(const CalendarSpec *spec, struct tm *tm, usec_t *usec) { struct tm c; int tm_usec; @@ -1224,7 +1228,7 @@ static int find_next(const CalendarSpec *spec, struct tm *tm, usec_t *usec) { c = *tm; tm_usec = *usec; - for (;;) { + for (unsigned iteration = 0; iteration < MAX_CALENDAR_ITERATIONS; iteration++) { /* Normalize the current date */ (void) mktime_or_timegm(&c, spec->utc); c.tm_isdst = spec->dst; @@ -1321,6 +1325,14 @@ static int find_next(const CalendarSpec *spec, struct tm *tm, usec_t *usec) { *usec = tm_usec; return 0; } + + /* It seems we entered an infinite loop. Let's gracefully return an error instead of hanging or + * aborting. This code is also exercised when timers.target is brought up during early boot, so + * aborting here is problematic and hard to diagnose for users. */ + _cleanup_free_ char *s = NULL; + (void) calendar_spec_to_string(spec, &s); + return log_warning_errno(SYNTHETIC_ERRNO(EDEADLK), + "Infinite loop in calendar calculation: %s", strna(s)); } static int calendar_spec_next_usec_impl(const CalendarSpec *spec, usec_t usec, usec_t *ret_next) { |