diff options
| -rw-r--r-- | kernel/time/timer.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 74591ba..bbc5d11 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -977,13 +977,29 @@ EXPORT_SYMBOL(add_timer); */ void add_timer_on(struct timer_list *timer, int cpu) { - struct tvec_base *base = per_cpu_ptr(&tvec_bases, cpu); + struct tvec_base *new_base = per_cpu_ptr(&tvec_bases, cpu); + struct tvec_base *base; unsigned long flags; timer_stats_timer_set_start_info(timer); BUG_ON(timer_pending(timer) || !timer->function); - spin_lock_irqsave(&base->lock, flags); - timer->flags = (timer->flags & ~TIMER_BASEMASK) | cpu; + + /* + * If @timer was on a different CPU, it should be migrated with the + * old base locked to prevent other operations proceeding with the + * wrong base locked. See lock_timer_base(). + */ + base = lock_timer_base(timer, &flags); + if (base != new_base) { + timer->flags |= TIMER_MIGRATING; + + spin_unlock(&base->lock); + base = new_base; + spin_lock(&base->lock); + WRITE_ONCE(timer->flags, + (timer->flags & ~TIMER_BASEMASK) | cpu); + } + debug_activate(timer, timer->expires); internal_add_timer(base, timer); spin_unlock_irqrestore(&base->lock, flags); |