diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/timekeeping.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 657414cf2e46..187149be83ea 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -148,6 +148,13 @@ static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr) /* calculate the delta since the last update_wall_time */ delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask); + /* + * Try to catch underflows by checking if we are seeing small + * mask-relative negative values. + */ + if (unlikely((~delta & tkr->mask) < (tkr->mask >> 3))) + delta = 0; + /* Cap delta value to the max_cycles values to avoid mult overflows */ if (unlikely(delta > tkr->clock->max_cycles)) delta = tkr->clock->max_cycles; |