21 files changed, 349 insertions, 112 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/kmod.c b/kernel/kmod.c
index fb326365b694..b086006c59e7 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -571,6 +571,10 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
         DECLARE_COMPLETION_ONSTACK(done);
         int retval = 0;
 
+        if (!sub_info->path) {
+                call_usermodehelper_freeinfo(sub_info);
+                return -EINVAL;
+        }
         helper_lock();
         if (!khelper_wq || usermodehelper_disabled) {
                 retval = -EBUSY;
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/pid.c b/kernel/pid.c
index ebe5e80b10f8..9b9a26698144 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -273,6 +273,11 @@ void free_pid(struct pid *pid)
                          */
                         wake_up_process(ns->child_reaper);
                         break;
+                case PIDNS_HASH_ADDING:
+                        /* Handle a fork failure of the first process */
+                        WARN_ON(ns->child_reaper);
+                        ns->nr_hashed = 0;
+                        /* fall through */
                 case 0:
                         schedule_work(&ns->proc_work);
                         break;
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 358a146fd4da..98c3b34a4cff 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -743,7 +743,10 @@ int create_basic_memory_bitmaps(void)
         struct memory_bitmap *bm1, *bm2;
         int error = 0;
 
-        BUG_ON(forbidden_pages_map || free_pages_map);
+        if (forbidden_pages_map && free_pages_map)
+                return 0;
+        else
+                BUG_ON(forbidden_pages_map || free_pages_map);
 
         bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
         if (!bm1)
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 72e8f4fd616d..957f06164ad1 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -39,6 +39,7 @@ static struct snapshot_data {
         char frozen;
         char ready;
         char platform_support;
+        bool free_bitmaps;
 } snapshot_state;
 
 atomic_t snapshot_device_available = ATOMIC_INIT(1);
@@ -82,6 +83,10 @@ static int snapshot_open(struct inode *inode, struct file *filp)
                 data->swap = -1;
                 data->mode = O_WRONLY;
                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
+                if (!error) {
+                        error = create_basic_memory_bitmaps();
+                        data->free_bitmaps = !error;
+                }
                 if (error)
                         pm_notifier_call_chain(PM_POST_RESTORE);
         }
@@ -111,6 +116,8 @@ static int snapshot_release(struct inode *inode, struct file *filp)
                 pm_restore_gfp_mask();
                 free_basic_memory_bitmaps();
                 thaw_processes();
+        } else if (data->free_bitmaps) {
+                free_basic_memory_bitmaps();
         }
         pm_notifier_call_chain(data->mode == O_RDONLY ?
                         PM_POST_HIBERNATION : PM_POST_RESTORE);
@@ -231,6 +238,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
                         break;
                 pm_restore_gfp_mask();
                 free_basic_memory_bitmaps();
+                data->free_bitmaps = false;
                 thaw_processes();
                 data->frozen = 0;
                 break;
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/debug.c b/kernel/sched/debug.c
index e076bddd4c66..196559994f7c 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -124,7 +124,7 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
                 SEQ_printf(m, " ");
 
         SEQ_printf(m, "%15s %5d %9Ld.%06ld %9Ld %5d ",
-                p->comm, p->pid,
+                p->comm, task_pid_nr(p),
                 SPLIT_NS(p->se.vruntime),
                 (long long)(p->nvcsw + p->nivcsw),
                 p->prio);
@@ -289,7 +289,7 @@ do {									\
         P(nr_load_updates);
         P(nr_uninterruptible);
         PN(next_balance);
-        P(curr->pid);
+        SEQ_printf(m, "  .%-30s: %ld\n", "curr->pid", (long)(task_pid_nr(rq->curr)));
         PN(clock);
         P(cpu_load[0]);
         P(cpu_load[1]);
@@ -492,7 +492,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
 {
         unsigned long nr_switches;
 
-        SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, p->pid,
+        SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr(p),
                                                 get_nr_threads(p));
         SEQ_printf(m,
                 "---------------------------------------------------------"
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9b3fe1cd8f40..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);
         }
@@ -5928,11 +5929,15 @@ static void task_fork_fair(struct task_struct *p)
         cfs_rq = task_cfs_rq(current);
         curr = cfs_rq->curr;
 
-        if (unlikely(task_cpu(p) != this_cpu)) {
-                rcu_read_lock();
-                __set_task_cpu(p, this_cpu);
-                rcu_read_unlock();
-        }
+        /*
+         * Not only the cpu but also the task_group of the parent might have
+         * been changed after parent->se.parent,cfs_rq were copied to
+         * child->se.parent,cfs_rq. So call __set_task_cpu() to make those
+         * of child point to valid ones.
+         */
+        rcu_read_lock();
+        __set_task_cpu(p, this_cpu);
+        rcu_read_unlock();
 
         update_curr(cfs_rq);
 
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 5aef494fc8b4..c7edee71bce8 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -104,8 +104,9 @@ static inline void sched_info_queued(struct task_struct *t)
 }
 
 /*
- * Called when a process ceases being the active-running process, either
- * voluntarily or involuntarily.  Now we can calculate how long we ran.
+ * Called when a process ceases being the active-running process involuntarily
+ * due, typically, to expiring its time slice (this may also be called when
+ * switching to the idle task).  Now we can calculate how long we ran.
  * Also, if the process is still in the TASK_RUNNING state, call
  * sched_info_queued() to mark that it has now again started waiting on
  * the runqueue.
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 53cc09ceb0b8..d7d498d8cc4f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -328,10 +328,19 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
-        if (!force_irqthreads)
-                __do_softirq();
-        else
+        if (!force_irqthreads) {
+                /*
+                 * We can safely execute softirq on the current stack if
+                 * it is the irq stack, because it should be near empty
+                 * at this stage. But we have no way to know if the arch
+                 * calls irq_exit() on the irq stack. So call softirq
+                 * in its own stack to prevent from any overrun on top
+                 * of a potentially deep task stack.
+                 */
+                do_softirq();
+        } else {
                 wakeup_softirqd();
+        }
 }
 
 static inline void tick_irq_exit(void)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 8f5b3b98577b..bb2215174f05 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -516,13 +516,13 @@ static void sync_cmos_clock(struct work_struct *work)
         schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
 }
 
-static void notify_cmos_timer(void)
+void ntp_notify_cmos_timer(void)
 {
         schedule_delayed_work(&sync_cmos_work, 0);
 }
 
 #else
-static inline void notify_cmos_timer(void) { }
+void ntp_notify_cmos_timer(void) { }
 #endif
 
 
@@ -687,8 +687,6 @@ int __do_adjtimex(struct timex *txc, struct timespec *ts, s32 *time_tai)
         if (!(time_status & STA_NANO))
                 txc->time.tv_usec /= NSEC_PER_USEC;
 
-        notify_cmos_timer();
-
         return result;
 }
 
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 48b9fffabdc2..947ba25a95a0 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1703,6 +1703,8 @@ int do_adjtimex(struct timex *txc)
         write_seqcount_end(&timekeeper_seq);
         raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
+        ntp_notify_cmos_timer();
+
         return ret;
 }
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 03cf44ac54d3..44e826a79665 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3641,7 +3641,7 @@ __setup("ftrace_filter=", set_ftrace_filter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
-static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
+static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
 
 static int __init set_graph_function(char *str)
 {
@@ -3659,7 +3659,7 @@ static void __init set_ftrace_early_graph(char *buf)
                 func = strsep(&buf, ",");
                 /* we allow only one expression at a time */
                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                      func);
+                                      FTRACE_GRAPH_MAX_FUNCS, func);
                 if (ret)
                         printk(KERN_DEBUG "ftrace: function %s not "
                                           "traceable\n", func);
@@ -3776,15 +3776,25 @@ static const struct file_operations ftrace_notrace_fops = {
 static DEFINE_MUTEX(graph_lock);
 
 int ftrace_graph_count;
-int ftrace_graph_filter_enabled;
+int ftrace_graph_notrace_count;
 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+
+struct ftrace_graph_data {
+        unsigned long *table;
+        size_t size;
+        int *count;
+        const struct seq_operations *seq_ops;
+};
 
 static void *
 __g_next(struct seq_file *m, loff_t *pos)
 {
-        if (*pos >= ftrace_graph_count)
+        struct ftrace_graph_data *fgd = m->private;
+
+        if (*pos >= *fgd->count)
                 return NULL;
-        return &ftrace_graph_funcs[*pos];
+        return &fgd->table[*pos];
 }
 
 static void *
@@ -3796,10 +3806,12 @@ g_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *g_start(struct seq_file *m, loff_t *pos)
 {
+        struct ftrace_graph_data *fgd = m->private;
+
         mutex_lock(&graph_lock);
 
         /* Nothing, tell g_show to print all functions are enabled */
-        if (!ftrace_graph_filter_enabled && !*pos)
+        if (!*fgd->count && !*pos)
                 return (void *)1;
 
         return __g_next(m, pos);
@@ -3835,38 +3847,88 @@ static const struct seq_operations ftrace_graph_seq_ops = {
 };
 
 static int
-ftrace_graph_open(struct inode *inode, struct file *file)
+__ftrace_graph_open(struct inode *inode, struct file *file,
+                    struct ftrace_graph_data *fgd)
 {
         int ret = 0;
 
-        if (unlikely(ftrace_disabled))
-                return -ENODEV;
-
         mutex_lock(&graph_lock);
         if ((file->f_mode & FMODE_WRITE) &&
             (file->f_flags & O_TRUNC)) {
-                ftrace_graph_filter_enabled = 0;
-                ftrace_graph_count = 0;
-                memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
+                *fgd->count = 0;
+                memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
         }
         mutex_unlock(&graph_lock);
 
-        if (file->f_mode & FMODE_READ)
-                ret = seq_open(file, &ftrace_graph_seq_ops);
+        if (file->f_mode & FMODE_READ) {
+                ret = seq_open(file, fgd->seq_ops);
+                if (!ret) {
+                        struct seq_file *m = file->private_data;
+                        m->private = fgd;
+                }
+        } else
+                file->private_data = fgd;
 
         return ret;
 }
 
 static int
+ftrace_graph_open(struct inode *inode, struct file *file)
+{
+        struct ftrace_graph_data *fgd;
+
+        if (unlikely(ftrace_disabled))
+                return -ENODEV;
+
+        fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+        if (fgd == NULL)
+                return -ENOMEM;
+
+        fgd->table = ftrace_graph_funcs;
+        fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+        fgd->count = &ftrace_graph_count;
+        fgd->seq_ops = &ftrace_graph_seq_ops;
+
+        return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
+ftrace_graph_notrace_open(struct inode *inode, struct file *file)
+{
+        struct ftrace_graph_data *fgd;
+
+        if (unlikely(ftrace_disabled))
+                return -ENODEV;
+
+        fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+        if (fgd == NULL)
+                return -ENOMEM;
+
+        fgd->table = ftrace_graph_notrace_funcs;
+        fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+        fgd->count = &ftrace_graph_notrace_count;
+        fgd->seq_ops = &ftrace_graph_seq_ops;
+
+        return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
 ftrace_graph_release(struct inode *inode, struct file *file)
 {
-        if (file->f_mode & FMODE_READ)
+        if (file->f_mode & FMODE_READ) {
+                struct seq_file *m = file->private_data;
+
+                kfree(m->private);
                 seq_release(inode, file);
+        } else {
+                kfree(file->private_data);
+        }
+
         return 0;
 }
 
 static int
-ftrace_set_func(unsigned long *array, int *idx, char *buffer)
+ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
 {
         struct dyn_ftrace *rec;
         struct ftrace_page *pg;
@@ -3879,7 +3941,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 
         /* decode regex */
         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
-        if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
+        if (!not && *idx >= size)
                 return -EBUSY;
 
         search_len = strlen(search);
@@ -3907,7 +3969,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
                                 fail = 0;
                                 if (!exists) {
                                         array[(*idx)++] = rec->ip;
-                                        if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
+                                        if (*idx >= size)
                                                 goto out;
                                 }
                         } else {
@@ -3925,8 +3987,6 @@ out:
         if (fail)
                 return -EINVAL;
 
-        ftrace_graph_filter_enabled = !!(*idx);
-
         return 0;
 }
 
@@ -3935,36 +3995,33 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
                    size_t cnt, loff_t *ppos)
 {
         struct trace_parser parser;
-        ssize_t read, ret;
+        ssize_t read, ret = 0;
+        struct ftrace_graph_data *fgd = file->private_data;
 
         if (!cnt)
                 return 0;
 
-        mutex_lock(&graph_lock);
-
-        if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
-                ret = -ENOMEM;
-                goto out_unlock;
-        }
+        if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
+                return -ENOMEM;
 
         read = trace_get_user(&parser, ubuf, cnt, ppos);
 
         if (read >= 0 && trace_parser_loaded((&parser))) {
                 parser.buffer[parser.idx] = 0;
 
+                mutex_lock(&graph_lock);
+
                 /* we allow only one expression at a time */
-                ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                        parser.buffer);
-                if (ret)
-                        goto out_free;
+                ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
+                                      parser.buffer);
+
+                mutex_unlock(&graph_lock);
         }
 
-        ret = read;
+        if (!ret)
+                ret = read;
 
-out_free:
         trace_parser_put(&parser);
-out_unlock:
-        mutex_unlock(&graph_lock);
 
         return ret;
 }
@@ -3976,6 +4033,14 @@ static const struct file_operations ftrace_graph_fops = {
         .llseek         = ftrace_filter_lseek,
         .release        = ftrace_graph_release,
 };
+
+static const struct file_operations ftrace_graph_notrace_fops = {
+        .open           = ftrace_graph_notrace_open,
+        .read           = seq_read,
+        .write          = ftrace_graph_write,
+        .llseek         = ftrace_filter_lseek,
+        .release        = ftrace_graph_release,
+};
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
@@ -3997,6 +4062,9 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
         trace_create_file("set_graph_function", 0444, d_tracer,
                                     NULL,
                                     &ftrace_graph_fops);
+        trace_create_file("set_graph_notrace", 0444, d_tracer,
+                                    NULL,
+                                    &ftrace_graph_notrace_fops);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
         return 0;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7974ba20557d..063a92bad578 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -843,9 +843,12 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
         if (isspace(ch)) {
                 parser->buffer[parser->idx] = 0;
                 parser->cont = false;
-        } else {
+        } else if (parser->idx < parser->size - 1) {
                 parser->cont = true;
                 parser->buffer[parser->idx++] = ch;
+        } else {
+                ret = -EINVAL;
+                goto out;
         }
 
         *ppos += read;
@@ -2760,7 +2763,7 @@ static void show_snapshot_main_help(struct seq_file *m)
         seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
         seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
         seq_printf(m, "#                      Takes a snapshot of the main buffer.\n");
-        seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
+        seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n");
         seq_printf(m, "#                      (Doesn't have to be '2' works with any number that\n");
         seq_printf(m, "#                       is not a '0' or '1')\n");
 }
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 10c86fb7a2b4..d1cf5159bec0 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -730,15 +730,16 @@ extern void __trace_graph_return(struct trace_array *tr,
 #ifdef CONFIG_DYNAMIC_FTRACE
 /* TODO: make this variable */
 #define FTRACE_GRAPH_MAX_FUNCS          32
-extern int ftrace_graph_filter_enabled;
 extern int ftrace_graph_count;
 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
+extern int ftrace_graph_notrace_count;
+extern unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS];
 
 static inline int ftrace_graph_addr(unsigned long addr)
 {
         int i;
 
-        if (!ftrace_graph_filter_enabled)
+        if (!ftrace_graph_count)
                 return 1;
 
         for (i = 0; i < ftrace_graph_count; i++) {
@@ -758,11 +759,31 @@ static inline int ftrace_graph_addr(unsigned long addr)
 
         return 0;
 }
+
+static inline int ftrace_graph_notrace_addr(unsigned long addr)
+{
+        int i;
+
+        if (!ftrace_graph_notrace_count)
+                return 0;
+
+        for (i = 0; i < ftrace_graph_notrace_count; i++) {
+                if (addr == ftrace_graph_notrace_funcs[i])
+                        return 1;
+        }
+
+        return 0;
+}
 #else
 static inline int ftrace_graph_addr(unsigned long addr)
 {
         return 1;
 }
+
+static inline int ftrace_graph_notrace_addr(unsigned long addr)
+{
+        return 0;
+}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
 static inline enum print_line_t
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index b5c09242683d..e08c030b8f38 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -114,16 +114,37 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
                 return -EBUSY;
         }
 
+        /*
+         * The curr_ret_stack is an index to ftrace return stack of
+         * current task.  Its value should be in [0, FTRACE_RETFUNC_
+         * DEPTH) when the function graph tracer is used.  To support
+         * filtering out specific functions, it makes the index
+         * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
+         * so when it sees a negative index the ftrace will ignore
+         * the record.  And the index gets recovered when returning
+         * from the filtered function by adding the FTRACE_NOTRACE_
+         * DEPTH and then it'll continue to record functions normally.
+         *
+         * The curr_ret_stack is initialized to -1 and get increased
+         * in this function.  So it can be less than -1 only if it was
+         * filtered out via ftrace_graph_notrace_addr() which can be
+         * set from set_graph_notrace file in debugfs by user.
+         */
+        if (current->curr_ret_stack < -1)
+                return -EBUSY;
+
         calltime = trace_clock_local();
 
         index = ++current->curr_ret_stack;
+        if (ftrace_graph_notrace_addr(func))
+                current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
         barrier();
         current->ret_stack[index].ret = ret;
         current->ret_stack[index].func = func;
         current->ret_stack[index].calltime = calltime;
         current->ret_stack[index].subtime = 0;
         current->ret_stack[index].fp = frame_pointer;
-        *depth = index;
+        *depth = current->curr_ret_stack;
 
         return 0;
 }
@@ -137,7 +158,17 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 
         index = current->curr_ret_stack;
 
-        if (unlikely(index < 0)) {
+        /*
+         * A negative index here means that it's just returned from a
+         * notrace'd function.  Recover index to get an original
+         * return address.  See ftrace_push_return_trace().
+         *
+         * TODO: Need to check whether the stack gets corrupted.
+         */
+        if (index < 0)
+                index += FTRACE_NOTRACE_DEPTH;
+
+        if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
                 ftrace_graph_stop();
                 WARN_ON(1);
                 /* Might as well panic, otherwise we have no where to go */
@@ -193,6 +224,15 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
         trace.rettime = trace_clock_local();
         barrier();
         current->curr_ret_stack--;
+        /*
+         * The curr_ret_stack can be less than -1 only if it was
+         * filtered out and it's about to return from the function.
+         * Recover the index and continue to trace normal functions.
+         */
+        if (current->curr_ret_stack < -1) {
+                current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
+                return ret;
+        }
 
         /*
          * The trace should run after decrementing the ret counter
@@ -259,10 +299,20 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
 
         /* trace it when it is-nested-in or is a function enabled. */
         if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
-             ftrace_graph_ignore_irqs()) ||
+             ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
             (max_depth && trace->depth >= max_depth))
                 return 0;
 
+        /*
+         * Do not trace a function if it's filtered by set_graph_notrace.
+         * Make the index of ret stack negative to indicate that it should
+         * ignore further functions.  But it needs its own ret stack entry
+         * to recover the original index in order to continue tracing after
+         * returning from the function.
+         */
+        if (ftrace_graph_notrace_addr(trace->func))
+                return 1;
+
         local_irq_save(flags);
         cpu = raw_smp_processor_id();
         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 847f88a6194b..7af67360b330 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -43,46 +43,15 @@ static DEFINE_MUTEX(all_stat_sessions_mutex);
 /* The root directory for all stat files */
 static struct dentry            *stat_dir;
 
-/*
- * Iterate through the rbtree using a post order traversal path
- * to release the next node.
- * It won't necessary release one at each iteration
- * but it will at least advance closer to the next one
- * to be released.
- */
-static struct rb_node *release_next(struct tracer_stat *ts,
-                                    struct rb_node *node)
+static void __reset_stat_session(struct stat_session *session)
 {
-        struct stat_node *snode;
-        struct rb_node *parent = rb_parent(node);
-
-        if (node->rb_left)
-                return node->rb_left;
-        else if (node->rb_right)
-                return node->rb_right;
-        else {
-                if (!parent)
-                        ;
-                else if (parent->rb_left == node)
-                        parent->rb_left = NULL;
-                else
-                        parent->rb_right = NULL;
+        struct stat_node *snode, *n;
 
-                snode = container_of(node, struct stat_node, node);
-                if (ts->stat_release)
-                        ts->stat_release(snode->stat);
+        rbtree_postorder_for_each_entry_safe(snode, n, &session->stat_root, node) {
+                if (session->ts->stat_release)
+                        session->ts->stat_release(snode->stat);
                 kfree(snode);
-
-                return parent;
         }
-}
-
-static void __reset_stat_session(struct stat_session *session)
-{
-        struct rb_node *node = session->stat_root.rb_node;
-
-        while (node)
-                node = release_next(session->ts, node);
 
         session->stat_root = RB_ROOT;
 }
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);
 }