13 files changed, 153 insertions, 36 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 13932abde159..a0123d75ec9a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2738,14 +2738,15 @@ void cgroup_fork_callbacks(struct task_struct *child)
  */
 void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
 {
-        struct cgroup *oldcgrp, *newcgrp;
+        struct cgroup *oldcgrp, *newcgrp = NULL;
 
         if (need_mm_owner_callback) {
                 int i;
                 for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
                         struct cgroup_subsys *ss = subsys[i];
                         oldcgrp = task_cgroup(old, ss->subsys_id);
-                        newcgrp = task_cgroup(new, ss->subsys_id);
+                        if (new)
+                                newcgrp = task_cgroup(new, ss->subsys_id);
                         if (oldcgrp == newcgrp)
                                 continue;
                         if (ss->mm_owner_changed)
diff --git a/kernel/dma-coherent.c b/kernel/dma-coherent.c
index c1d4d5b4c61c..f013a0c2e111 100644
--- a/kernel/dma-coherent.c
+++ b/kernel/dma-coherent.c
@@ -124,6 +124,7 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size,
         }
         return (mem != NULL);
 }
+EXPORT_SYMBOL(dma_alloc_from_coherent);
 
 /**
  * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
@@ -151,3 +152,4 @@ int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
         }
         return 0;
 }
+EXPORT_SYMBOL(dma_release_from_coherent);
diff --git a/kernel/exit.c b/kernel/exit.c
index 16395644a98f..85a83c831856 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -583,8 +583,6 @@ mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
          * If there are other users of the mm and the owner (us) is exiting
          * we need to find a new owner to take on the responsibility.
          */
-        if (!mm)
-                return 0;
         if (atomic_read(&mm->mm_users) <= 1)
                 return 0;
         if (mm->owner != p)
@@ -627,6 +625,16 @@ retry:
         } while_each_thread(g, c);
 
         read_unlock(&tasklist_lock);
+        /*
+         * We found no owner yet mm_users > 1: this implies that we are
+         * most likely racing with swapoff (try_to_unuse()) or /proc or
+         * ptrace or page migration (get_task_mm()).  Mark owner as NULL,
+         * so that subsystems can understand the callback and take action.
+         */
+        down_write(&mm->mmap_sem);
+        cgroup_mm_owner_callbacks(mm->owner, NULL);
+        mm->owner = NULL;
+        up_write(&mm->mmap_sem);
         return;
 
 assign_new_owner:
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index b8e4dce80a74..cdec83e722fa 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -672,13 +672,14 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
                          */
                         BUG_ON(timer->function(timer) != HRTIMER_NORESTART);
                         return 1;
-                case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ:
+                case HRTIMER_CB_IRQSAFE_PERCPU:
+                case HRTIMER_CB_IRQSAFE_UNLOCKED:
                         /*
                          * This is solely for the sched tick emulation with
                          * dynamic tick support to ensure that we do not
                          * restart the tick right on the edge and end up with
                          * the tick timer in the softirq ! The calling site
-                         * takes care of this.
+                         * takes care of this. Also used for hrtimer sleeper !
                          */
                         debug_hrtimer_deactivate(timer);
                         return 1;
@@ -1245,7 +1246,8 @@ static void __run_hrtimer(struct hrtimer *timer)
         timer_stats_account_hrtimer(timer);
 
         fn = timer->function;
-        if (timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ) {
+        if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU ||
+            timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED) {
                 /*
                  * Used for scheduler timers, avoid lock inversion with
                  * rq->lock and tasklist_lock.
@@ -1452,7 +1454,7 @@ void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
         sl->timer.function = hrtimer_wakeup;
         sl->task = task;
 #ifdef CONFIG_HIGH_RES_TIMERS
-        sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+        sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED;
 #endif
 }
 
@@ -1591,29 +1593,95 @@ static void __cpuinit init_hrtimers_cpu(int cpu)
 
 #ifdef CONFIG_HOTPLUG_CPU
 
-static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
-                                struct hrtimer_clock_base *new_base)
+static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+                                struct hrtimer_clock_base *new_base, int dcpu)
 {
         struct hrtimer *timer;
         struct rb_node *node;
+        int raise = 0;
 
         while ((node = rb_first(&old_base->active))) {
                 timer = rb_entry(node, struct hrtimer, node);
                 BUG_ON(hrtimer_callback_running(timer));
                 debug_hrtimer_deactivate(timer);
-                __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
+
+                /*
+                 * Should not happen. Per CPU timers should be
+                 * canceled _before_ the migration code is called
+                 */
+                if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU) {
+                        __remove_hrtimer(timer, old_base,
+                                         HRTIMER_STATE_INACTIVE, 0);
+                        WARN(1, "hrtimer (%p %p)active but cpu %d dead\n",
+                             timer, timer->function, dcpu);
+                        continue;
+                }
+
+                /*
+                 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
+                 * timer could be seen as !active and just vanish away
+                 * under us on another CPU
+                 */
+                __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
                 timer->base = new_base;
                 /*
                  * Enqueue the timer. Allow reprogramming of the event device
                  */
                 enqueue_hrtimer(timer, new_base, 1);
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+                /*
+                 * Happens with high res enabled when the timer was
+                 * already expired and the callback mode is
+                 * HRTIMER_CB_IRQSAFE_UNLOCKED (hrtimer_sleeper). The
+                 * enqueue code does not move them to the soft irq
+                 * pending list for performance/latency reasons, but
+                 * in the migration state, we need to do that
+                 * otherwise we end up with a stale timer.
+                 */
+                if (timer->state == HRTIMER_STATE_MIGRATE) {
+                        timer->state = HRTIMER_STATE_PENDING;
+                        list_add_tail(&timer->cb_entry,
+                                      &new_base->cpu_base->cb_pending);
+                        raise = 1;
+                }
+#endif
+                /* Clear the migration state bit */
+                timer->state &= ~HRTIMER_STATE_MIGRATE;
+        }
+        return raise;
+}
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
+                                   struct hrtimer_cpu_base *new_base)
+{
+        struct hrtimer *timer;
+        int raise = 0;
+
+        while (!list_empty(&old_base->cb_pending)) {
+                timer = list_entry(old_base->cb_pending.next,
+                                   struct hrtimer, cb_entry);
+
+                __remove_hrtimer(timer, timer->base, HRTIMER_STATE_PENDING, 0);
+                timer->base = &new_base->clock_base[timer->base->index];
+                list_add_tail(&timer->cb_entry, &new_base->cb_pending);
+                raise = 1;
         }
+        return raise;
+}
+#else
+static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
+                                   struct hrtimer_cpu_base *new_base)
+{
+        return 0;
 }
+#endif
 
 static void migrate_hrtimers(int cpu)
 {
         struct hrtimer_cpu_base *old_base, *new_base;
-        int i;
+        int i, raise = 0;
 
         BUG_ON(cpu_online(cpu));
         old_base = &per_cpu(hrtimer_bases, cpu);
@@ -1626,14 +1694,21 @@ static void migrate_hrtimers(int cpu)
         spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
-                migrate_hrtimer_list(&old_base->clock_base[i],
-                                     &new_base->clock_base[i]);
+                if (migrate_hrtimer_list(&old_base->clock_base[i],
+                                         &new_base->clock_base[i], cpu))
+                        raise = 1;
         }
 
+        if (migrate_hrtimer_pending(old_base, new_base))
+                raise = 1;
+
         spin_unlock(&old_base->lock);
         spin_unlock(&new_base->lock);
         local_irq_enable();
         put_cpu_var(hrtimer_bases);
+
+        if (raise)
+                hrtimer_raise_softirq();
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 59f3f0df35d4..aef265325cd3 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -753,8 +753,14 @@ static struct page *kimage_alloc_page(struct kimage *image,
                         *old = addr | (*old & ~PAGE_MASK);
 
                         /* The old page I have found cannot be a
-                         * destination page, so return it.
+                         * destination page, so return it if it's
+                         * gfp_flags honor the ones passed in.
                          */
+                        if (!(gfp_mask & __GFP_HIGHMEM) &&
+                            PageHighMem(old_page)) {
+                                kimage_free_pages(old_page);
+                                continue;
+                        }
                         addr = old_addr;
                         page = old_page;
                         break;
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index eaa21fc9ad1d..e4dcfb2272a4 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -488,7 +488,7 @@ static int write_mem_msg(int binary)
                 if (err)
                         return err;
                 if (CACHE_FLUSH_IS_SAFE)
-                        flush_icache_range(addr, addr + length + 1);
+                        flush_icache_range(addr, addr + length);
                 return 0;
         }
 
@@ -590,6 +590,7 @@ static void kgdb_wait(struct pt_regs *regs)
 
         /* Signal the primary CPU that we are done: */
         atomic_set(&cpu_in_kgdb[cpu], 0);
+        touch_softlockup_watchdog();
         clocksource_touch_watchdog();
         local_irq_restore(flags);
 }
@@ -1432,6 +1433,7 @@ acquirelock:
             atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
 
                 atomic_set(&kgdb_active, -1);
+                touch_softlockup_watchdog();
                 clocksource_touch_watchdog();
                 local_irq_restore(flags);
 
@@ -1462,7 +1464,7 @@ acquirelock:
          * Get the passive CPU lock which will hold all the non-primary
          * CPU in a spin state while the debugger is active
          */
-        if (!kgdb_single_step || !kgdb_contthread) {
+        if (!kgdb_single_step) {
                 for (i = 0; i < NR_CPUS; i++)
                         atomic_set(&passive_cpu_wait[i], 1);
         }
@@ -1475,7 +1477,7 @@ acquirelock:
 
 #ifdef CONFIG_SMP
         /* Signal the other CPUs to enter kgdb_wait() */
-        if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup)
+        if ((!kgdb_single_step) && kgdb_do_roundup)
                 kgdb_roundup_cpus(flags);
 #endif
 
@@ -1494,7 +1496,7 @@ acquirelock:
         kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
         kgdb_deactivate_sw_breakpoints();
         kgdb_single_step = 0;
-        kgdb_contthread = NULL;
+        kgdb_contthread = current;
         exception_level = 0;
 
         /* Talk to debugger with gdbserial protocol */
@@ -1508,7 +1510,7 @@ acquirelock:
         kgdb_info[ks->cpu].task = NULL;
         atomic_set(&cpu_in_kgdb[ks->cpu], 0);
 
-        if (!kgdb_single_step || !kgdb_contthread) {
+        if (!kgdb_single_step) {
                 for (i = NR_CPUS-1; i >= 0; i--)
                         atomic_set(&passive_cpu_wait[i], 0);
                 /*
@@ -1524,6 +1526,7 @@ acquirelock:
 kgdb_restore:
         /* Free kgdb_active */
         atomic_set(&kgdb_active, -1);
+        touch_softlockup_watchdog();
         clocksource_touch_watchdog();
         local_irq_restore(flags);
 
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index e36d5798cbff..5131e5471169 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -441,7 +441,7 @@ static struct k_itimer * alloc_posix_timer(void)
                 return tmr;
         if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
                 kmem_cache_free(posix_timers_cache, tmr);
-                tmr = NULL;
+                return NULL;
         }
         memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
         return tmr;
diff --git a/kernel/sched.c b/kernel/sched.c
index 98890807375b..ad1962dc0aa2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -201,7 +201,7 @@ void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
         hrtimer_init(&rt_b->rt_period_timer,
                         CLOCK_MONOTONIC, HRTIMER_MODE_REL);
         rt_b->rt_period_timer.function = sched_rt_period_timer;
-        rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+        rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED;
 }
 
 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
@@ -1087,7 +1087,7 @@ hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
         return NOTIFY_DONE;
 }
 
-static void init_hrtick(void)
+static __init void init_hrtick(void)
 {
         hotcpu_notifier(hotplug_hrtick, 0);
 }
@@ -1119,7 +1119,7 @@ static void init_rq_hrtick(struct rq *rq)
 
         hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
         rq->hrtick_timer.function = hrtick;
-        rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+        rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
 }
 #else
 static inline void hrtick_clear(struct rq *rq)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index f1f3eee28113..cb01cd8f919b 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -235,7 +235,8 @@ static void tick_do_broadcast_on_off(void *why)
         case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
                 if (!cpu_isset(cpu, tick_broadcast_mask)) {
                         cpu_set(cpu, tick_broadcast_mask);
-                        if (td->mode == TICKDEV_MODE_PERIODIC)
+                        if (tick_broadcast_device.mode ==
+                            TICKDEV_MODE_PERIODIC)
                                 clockevents_shutdown(dev);
                 }
                 if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
@@ -245,7 +246,8 @@ static void tick_do_broadcast_on_off(void *why)
                 if (!tick_broadcast_force &&
                     cpu_isset(cpu, tick_broadcast_mask)) {
                         cpu_clear(cpu, tick_broadcast_mask);
-                        if (td->mode == TICKDEV_MODE_PERIODIC)
+                        if (tick_broadcast_device.mode ==
+                            TICKDEV_MODE_PERIODIC)
                                 tick_setup_periodic(dev, 0);
                 }
                 break;
@@ -575,4 +577,12 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
         spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
 
+/*
+ * Check, whether the broadcast device is in one shot mode
+ */
+int tick_broadcast_oneshot_active(void)
+{
+        return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
+}
+
 #endif
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 019315ebf9de..df12434b43ca 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -33,7 +33,7 @@ DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
  */
 ktime_t tick_next_period;
 ktime_t tick_period;
-int tick_do_timer_cpu __read_mostly = -1;
+int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
 DEFINE_SPINLOCK(tick_device_lock);
 
 /*
@@ -109,7 +109,8 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
         if (!tick_device_is_functional(dev))
                 return;
 
-        if (dev->features & CLOCK_EVT_FEAT_PERIODIC) {
+        if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
+            !tick_broadcast_oneshot_active()) {
                 clockevents_set_mode(dev, CLOCK_EVT_MODE_PERIODIC);
         } else {
                 unsigned long seq;
@@ -148,7 +149,7 @@ static void tick_setup_device(struct tick_device *td,
                  * If no cpu took the do_timer update, assign it to
                  * this cpu:
                  */
-                if (tick_do_timer_cpu == -1) {
+                if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
                         tick_do_timer_cpu = cpu;
                         tick_next_period = ktime_get();
                         tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
@@ -300,7 +301,8 @@ static void tick_shutdown(unsigned int *cpup)
         if (*cpup == tick_do_timer_cpu) {
                 int cpu = first_cpu(cpu_online_map);
 
-                tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu : -1;
+                tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu :
+                        TICK_DO_TIMER_NONE;
         }
         spin_unlock_irqrestore(&tick_device_lock, flags);
 }
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 6e9db9734aa6..469248782c23 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -1,6 +1,10 @@
 /*
  * tick internal variable and functions used by low/high res code
  */
+
+#define TICK_DO_TIMER_NONE      -1
+#define TICK_DO_TIMER_BOOT      -2
+
 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
 extern spinlock_t tick_device_lock;
 extern ktime_t tick_next_period;
@@ -31,6 +35,7 @@ extern void tick_broadcast_oneshot_control(unsigned long reason);
 extern void tick_broadcast_switch_to_oneshot(void);
 extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup);
 extern int tick_resume_broadcast_oneshot(struct clock_event_device *bc);
+extern int tick_broadcast_oneshot_active(void);
 # else /* BROADCAST */
 static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
@@ -39,6 +44,7 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 static inline void tick_broadcast_oneshot_control(unsigned long reason) { }
 static inline void tick_broadcast_switch_to_oneshot(void) { }
 static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { }
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
 # endif /* !BROADCAST */
 
 #else /* !ONESHOT */
@@ -68,6 +74,7 @@ static inline int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
 {
         return 0;
 }
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
 #endif /* !TICK_ONESHOT */
 
 /*
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index a87b0468568b..cb02324bdb88 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -75,6 +75,9 @@ static void tick_do_update_jiffies64(ktime_t now)
                                                            incr * ticks);
                 }
                 do_timer(++ticks);
+
+                /* Keep the tick_next_period variable up to date */
+                tick_next_period = ktime_add(last_jiffies_update, tick_period);
         }
         write_sequnlock(&xtime_lock);
 }
@@ -221,7 +224,7 @@ void tick_nohz_stop_sched_tick(int inidle)
          */
         if (unlikely(!cpu_online(cpu))) {
                 if (cpu == tick_do_timer_cpu)
-                        tick_do_timer_cpu = -1;
+                        tick_do_timer_cpu = TICK_DO_TIMER_NONE;
         }
 
         if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
@@ -303,7 +306,7 @@ void tick_nohz_stop_sched_tick(int inidle)
                  * invoked.
                  */
                 if (cpu == tick_do_timer_cpu)
-                        tick_do_timer_cpu = -1;
+                        tick_do_timer_cpu = TICK_DO_TIMER_NONE;
 
                 ts->idle_sleeps++;
 
@@ -468,7 +471,7 @@ static void tick_nohz_handler(struct clock_event_device *dev)
          * this duty, then the jiffies update is still serialized by
          * xtime_lock.
          */
-        if (unlikely(tick_do_timer_cpu == -1))
+        if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                 tick_do_timer_cpu = cpu;
 
         /* Check, if the jiffies need an update */
@@ -570,7 +573,7 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
          * this duty, then the jiffies update is still serialized by
          * xtime_lock.
          */
-        if (unlikely(tick_do_timer_cpu == -1))
+        if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                 tick_do_timer_cpu = cpu;
 #endif
 
@@ -622,7 +625,7 @@ void tick_setup_sched_timer(void)
          */
         hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
         ts->sched_timer.function = tick_sched_timer;
-        ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+        ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
 
         /* Get the next period (per cpu) */
         ts->sched_timer.expires = tick_init_jiffy_update();
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index bb948e52ce20..db58fb66a135 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -202,7 +202,7 @@ static void start_stack_timer(int cpu)
 
         hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
         hrtimer->function = stack_trace_timer_fn;
-        hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+        hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
 
         hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL);
 }