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Commit 4f51d57f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull timer fixes from Thomas Gleixner:
 "Three fixlets for timers:

   - Two hot-fixes for the alarmtimer based posix timers, which prevent
     a nasty DOS by self rescheduling timers. The proper cleanup of that
     mess is queued for 4.13

   - Make a function static"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick/broadcast: Make tick_broadcast_setup_oneshot() static
  alarmtimer: Rate limit periodic intervals
  alarmtimer: Prevent overflow of relative timers
parents 0be5255c 94114c36

kernel/time/alarmtimer.c

+11 −3
Original line number Diff line number Diff line
@@ -387,7 +387,7 @@ void alarm_start_relative(struct alarm *alarm, ktime_t start) 
{

	struct alarm_base *base = &alarm_bases[alarm->type];



	start = ktime_add(start, base->gettime());

	start = ktime_add_safe(start, base->gettime());

	alarm_start(alarm, start);

}

EXPORT_SYMBOL_GPL(alarm_start_relative);
@@ -475,7 +475,7 @@ u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval) 
		overrun++;

	}



	alarm->node.expires = ktime_add(alarm->node.expires, interval);

	alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);

	return overrun;

}

EXPORT_SYMBOL_GPL(alarm_forward);
@@ -660,13 +660,21 @@ static int alarm_timer_set(struct k_itimer *timr, int flags, 


	/* start the timer */

	timr->it.alarm.interval = timespec64_to_ktime(new_setting->it_interval);



	/*

	 * Rate limit to the tick as a hot fix to prevent DOS. Will be

	 * mopped up later.

	 */

	if (timr->it.alarm.interval < TICK_NSEC)

		timr->it.alarm.interval = TICK_NSEC;



	exp = timespec64_to_ktime(new_setting->it_value);

	/* Convert (if necessary) to absolute time */

	if (flags != TIMER_ABSTIME) {

		ktime_t now;



		now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();

		exp = ktime_add(now, exp);

		exp = ktime_add_safe(now, exp);

	}



	alarm_start(&timr->it.alarm.alarmtimer, exp);

kernel/time/tick-broadcast.c

+3 −1
Original line number Diff line number Diff line
@@ -37,9 +37,11 @@ static int tick_broadcast_forced; 
static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(tick_broadcast_lock);



#ifdef CONFIG_TICK_ONESHOT

static void tick_broadcast_setup_oneshot(struct clock_event_device *bc);

static void tick_broadcast_clear_oneshot(int cpu);

static void tick_resume_broadcast_oneshot(struct clock_event_device *bc);

#else

static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { BUG(); }

static inline void tick_broadcast_clear_oneshot(int cpu) { }

static inline void tick_resume_broadcast_oneshot(struct clock_event_device *bc) { }

#endif
@@ -867,7 +869,7 @@ static void tick_broadcast_init_next_event(struct cpumask *mask, 
/**

 * tick_broadcast_setup_oneshot - setup the broadcast device

 */

void tick_broadcast_setup_oneshot(struct clock_event_device *bc)

static void tick_broadcast_setup_oneshot(struct clock_event_device *bc)

{

	int cpu = smp_processor_id();

kernel/time/tick-internal.h

+0 −2
Original line number Diff line number Diff line
@@ -126,7 +126,6 @@ static inline int tick_check_oneshot_change(int allow_nohz) { return 0; } 


/* Functions related to oneshot broadcasting */

#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)

extern void tick_broadcast_setup_oneshot(struct clock_event_device *bc);

extern void tick_broadcast_switch_to_oneshot(void);

extern void tick_shutdown_broadcast_oneshot(unsigned int cpu);

extern int tick_broadcast_oneshot_active(void);
@@ -134,7 +133,6 @@ extern void tick_check_oneshot_broadcast_this_cpu(void); 
bool tick_broadcast_oneshot_available(void);

extern struct cpumask *tick_get_broadcast_oneshot_mask(void);

#else /* !(BROADCAST && ONESHOT): */

static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { BUG(); }

static inline void tick_broadcast_switch_to_oneshot(void) { }

static inline void tick_shutdown_broadcast_oneshot(unsigned int cpu) { }

static inline int tick_broadcast_oneshot_active(void) { return 0; }