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authorLinus Torvalds <torvalds@linux-foundation.org>2017-06-18 18:46:51 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2017-06-18 18:46:51 +0900
commit4f51d57f3ff0f30bd805ff5bd04587a6145e1f73 (patch)
treef9334e57cfbdeafd8d36ddfd99cca66032cd771f
parent0be5255c88dace8b4e0ef19f2a9c3d0f3598c6e6 (diff)
parent94114c367553f3301747e47f6947cabde947575f (diff)
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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
-rw-r--r--kernel/time/alarmtimer.c14
-rw-r--r--kernel/time/tick-broadcast.c4
-rw-r--r--kernel/time/tick-internal.h2
3 files changed, 14 insertions, 6 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 5cb5b0008d97..ee2f4202d82a 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -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);
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 987e496bb51a..b398c2ea69b2 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -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();
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f738251000fe..be0ac01f2e12 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -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; }