7 files changed, 107 insertions, 15 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index 91e53d04b6a9..7b0e23a740ce 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1117,9 +1117,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 
                         sleep_time = timeout_start + audit_backlog_wait_time -
                                         jiffies;
-                        if ((long)sleep_time > 0)
+                        if ((long)sleep_time > 0) {
                                 wait_for_auditd(sleep_time);
-                        continue;
+                                continue;
+                        }
                 }
                 if (audit_rate_check() && printk_ratelimit())
                         printk(KERN_WARNING
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 247091bf0587..859c8dfd78a1 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -51,6 +51,15 @@ void context_tracking_user_enter(void)
         unsigned long flags;
 
         /*
+         * Repeat the user_enter() check here because some archs may be calling
+         * this from asm and if no CPU needs context tracking, they shouldn't
+         * go further. Repeat the check here until they support the static key
+         * check.
+         */
+        if (!static_key_false(&context_tracking_enabled))
+                return;
+
+        /*
          * Some contexts may involve an exception occuring in an irq,
          * leading to that nesting:
          * rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit()
@@ -151,6 +160,9 @@ void context_tracking_user_exit(void)
 {
         unsigned long flags;
 
+        if (!static_key_false(&context_tracking_enabled))
+                return;
+
         if (in_interrupt())
                 return;
 
diff --git a/kernel/events/core.c b/kernel/events/core.c
index dd236b66ca3a..cb4238e85b38 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3660,6 +3660,26 @@ static void calc_timer_values(struct perf_event *event,
         *running = ctx_time - event->tstamp_running;
 }
 
+static void perf_event_init_userpage(struct perf_event *event)
+{
+        struct perf_event_mmap_page *userpg;
+        struct ring_buffer *rb;
+
+        rcu_read_lock();
+        rb = rcu_dereference(event->rb);
+        if (!rb)
+                goto unlock;
+
+        userpg = rb->user_page;
+
+        /* Allow new userspace to detect that bit 0 is deprecated */
+        userpg->cap_bit0_is_deprecated = 1;
+        userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
+
+unlock:
+        rcu_read_unlock();
+}
+
 void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
 {
 }
@@ -4044,6 +4064,7 @@ again:
         ring_buffer_attach(event, rb);
         rcu_assign_pointer(event->rb, rb);
 
+        perf_event_init_userpage(event);
         perf_event_update_userpage(event);
 
 unlock:
diff --git a/kernel/params.c b/kernel/params.c
index 81c4e78c8f4c..c00d5b502aa4 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -254,11 +254,11 @@ int parse_args(const char *doing,
 
 
 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtoul);
+STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtol);
 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(int, int, "%i", long, kstrtoul);
+STANDARD_PARAM_DEF(int, int, "%i", long, kstrtol);
 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, kstrtoul);
-STANDARD_PARAM_DEF(long, long, "%li", long, kstrtoul);
+STANDARD_PARAM_DEF(long, long, "%li", long, kstrtol);
 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, kstrtoul);
 
 int param_set_charp(const char *val, const struct kernel_param *kp)
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 269ed9384cc4..f813b3474646 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -32,7 +32,14 @@ EXPORT_SYMBOL(cad_pid);
 #endif
 enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
 
-int reboot_default;
+/*
+ * This variable is used privately to keep track of whether or not
+ * reboot_type is still set to its default value (i.e., reboot= hasn't
+ * been set on the command line).  This is needed so that we can
+ * suppress DMI scanning for reboot quirks.  Without it, it's
+ * impossible to override a faulty reboot quirk without recompiling.
+ */
+int reboot_default = 1;
 int reboot_cpu;
 enum reboot_type reboot_type = BOOT_ACPI;
 int reboot_force;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 11cd13667359..7c70201fbc61 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4242,7 +4242,7 @@ static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq)
         }
 
         if (!se) {
-                cfs_rq->h_load = rq->avg.load_avg_contrib;
+                cfs_rq->h_load = cfs_rq->runnable_load_avg;
                 cfs_rq->last_h_load_update = now;
         }
 
@@ -4823,8 +4823,8 @@ void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
                 (busiest->load_per_task * SCHED_POWER_SCALE) /
                 busiest->group_power;
 
-        if (busiest->avg_load - local->avg_load + scaled_busy_load_per_task >=
-            (scaled_busy_load_per_task * imbn)) {
+        if (busiest->avg_load + scaled_busy_load_per_task >=
+            local->avg_load + (scaled_busy_load_per_task * imbn)) {
                 env->imbalance = busiest->load_per_task;
                 return;
         }
@@ -4896,7 +4896,8 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
          * max load less than avg load(as we skip the groups at or below
          * its cpu_power, while calculating max_load..)
          */
-        if (busiest->avg_load < sds->avg_load) {
+        if (busiest->avg_load <= sds->avg_load ||
+            local->avg_load >= sds->avg_load) {
                 env->imbalance = 0;
                 return fix_small_imbalance(env, sds);
         }
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 51c4f34d258e..4431610f049a 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -486,7 +486,52 @@ static struct smp_hotplug_thread watchdog_threads = {
         .unpark                 = watchdog_enable,
 };
 
-static int watchdog_enable_all_cpus(void)
+static void restart_watchdog_hrtimer(void *info)
+{
+        struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
+        int ret;
+
+        /*
+         * No need to cancel and restart hrtimer if it is currently executing
+         * because it will reprogram itself with the new period now.
+         * We should never see it unqueued here because we are running per-cpu
+         * with interrupts disabled.
+         */
+        ret = hrtimer_try_to_cancel(hrtimer);
+        if (ret == 1)
+                hrtimer_start(hrtimer, ns_to_ktime(sample_period),
+                                HRTIMER_MODE_REL_PINNED);
+}
+
+static void update_timers(int cpu)
+{
+        struct call_single_data data = {.func = restart_watchdog_hrtimer};
+        /*
+         * Make sure that perf event counter will adopt to a new
+         * sampling period. Updating the sampling period directly would
+         * be much nicer but we do not have an API for that now so
+         * let's use a big hammer.
+         * Hrtimer will adopt the new period on the next tick but this
+         * might be late already so we have to restart the timer as well.
+         */
+        watchdog_nmi_disable(cpu);
+        __smp_call_function_single(cpu, &data, 1);
+        watchdog_nmi_enable(cpu);
+}
+
+static void update_timers_all_cpus(void)
+{
+        int cpu;
+
+        get_online_cpus();
+        preempt_disable();
+        for_each_online_cpu(cpu)
+                update_timers(cpu);
+        preempt_enable();
+        put_online_cpus();
+}
+
+static int watchdog_enable_all_cpus(bool sample_period_changed)
 {
         int err = 0;
 
@@ -496,6 +541,8 @@ static int watchdog_enable_all_cpus(void)
                         pr_err("Failed to create watchdog threads, disabled\n");
                 else
                         watchdog_running = 1;
+        } else if (sample_period_changed) {
+                update_timers_all_cpus();
         }
 
         return err;
@@ -520,13 +567,15 @@ int proc_dowatchdog(struct ctl_table *table, int write,
                     void __user *buffer, size_t *lenp, loff_t *ppos)
 {
         int err, old_thresh, old_enabled;
+        static DEFINE_MUTEX(watchdog_proc_mutex);
 
+        mutex_lock(&watchdog_proc_mutex);
         old_thresh = ACCESS_ONCE(watchdog_thresh);
         old_enabled = ACCESS_ONCE(watchdog_user_enabled);
 
         err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
         if (err || !write)
-                return err;
+                goto out;
 
         set_sample_period();
         /*
@@ -535,7 +584,7 @@ int proc_dowatchdog(struct ctl_table *table, int write,
          * watchdog_*_all_cpus() function takes care of this.
          */
         if (watchdog_user_enabled && watchdog_thresh)
-                err = watchdog_enable_all_cpus();
+                err = watchdog_enable_all_cpus(old_thresh != watchdog_thresh);
         else
                 watchdog_disable_all_cpus();
 
@@ -544,7 +593,8 @@ int proc_dowatchdog(struct ctl_table *table, int write,
                 watchdog_thresh = old_thresh;
                 watchdog_user_enabled = old_enabled;
         }
-
+out:
+        mutex_unlock(&watchdog_proc_mutex);
         return err;
 }
 #endif /* CONFIG_SYSCTL */
@@ -554,5 +604,5 @@ void __init lockup_detector_init(void)
         set_sample_period();
 
         if (watchdog_user_enabled)
-                watchdog_enable_all_cpus();
+                watchdog_enable_all_cpus(false);
 }