Merge commit 'tracing/core' into tracing/kprobes

Conflicts:
	kernel/trace/trace_export.c
	kernel/trace/trace_kprobe.c

Merge reason: This topic branch lacks an important
build fix in tracing/core:

	0dd7b74787eaf7858c6c573353a83c3e2766e674:
	tracing: Fix double CPP substitution in TRACE_EVENT_FN

that prevents from multiple tracepoint headers inclusion crashes.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

19 files changed, 543 insertions, 311 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index fb5fbf75f279..e78dcbde1a81 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -60,9 +60,14 @@ config EVENT_TRACING
         bool
 
 config CONTEXT_SWITCH_TRACER
-        select MARKERS
         bool
 
+config RING_BUFFER_ALLOW_SWAP
+        bool
+        help
+         Allow the use of ring_buffer_swap_cpu.
+         Adds a very slight overhead to tracing when enabled.
+
 # All tracer options should select GENERIC_TRACER. For those options that are
 # enabled by all tracers (context switch and event tracer) they select TRACING.
 # This allows those options to appear when no other tracer is selected. But the
@@ -147,6 +152,7 @@ config IRQSOFF_TRACER
         select TRACE_IRQFLAGS
         select GENERIC_TRACER
         select TRACER_MAX_TRACE
+        select RING_BUFFER_ALLOW_SWAP
         help
           This option measures the time spent in irqs-off critical
           sections, with microsecond accuracy.
@@ -168,6 +174,7 @@ config PREEMPT_TRACER
         depends on PREEMPT
         select GENERIC_TRACER
         select TRACER_MAX_TRACE
+        select RING_BUFFER_ALLOW_SWAP
         help
           This option measures the time spent in preemption off critical
           sections, with microsecond accuracy.
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 1090b0aed9ba..3eb159c277c8 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -65,13 +65,15 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
 {
         struct blk_io_trace *t;
         struct ring_buffer_event *event = NULL;
+        struct ring_buffer *buffer = NULL;
         int pc = 0;
         int cpu = smp_processor_id();
         bool blk_tracer = blk_tracer_enabled;
 
         if (blk_tracer) {
+                buffer = blk_tr->buffer;
                 pc = preempt_count();
-                event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
+                event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
                                                   sizeof(*t) + len,
                                                   0, pc);
                 if (!event)
@@ -96,7 +98,7 @@ record_it:
                 memcpy((void *) t + sizeof(*t), data, len);
 
                 if (blk_tracer)
-                        trace_buffer_unlock_commit(blk_tr, event, 0, pc);
+                        trace_buffer_unlock_commit(buffer, event, 0, pc);
         }
 }
 
@@ -179,6 +181,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 {
         struct task_struct *tsk = current;
         struct ring_buffer_event *event = NULL;
+        struct ring_buffer *buffer = NULL;
         struct blk_io_trace *t;
         unsigned long flags = 0;
         unsigned long *sequence;
@@ -204,8 +207,9 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
         if (blk_tracer) {
                 tracing_record_cmdline(current);
 
+                buffer = blk_tr->buffer;
                 pc = preempt_count();
-                event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
+                event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
                                                   sizeof(*t) + pdu_len,
                                                   0, pc);
                 if (!event)
@@ -252,7 +256,7 @@ record_it:
                         memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
 
                 if (blk_tracer) {
-                        trace_buffer_unlock_commit(blk_tr, event, 0, pc);
+                        trace_buffer_unlock_commit(buffer, event, 0, pc);
                         return;
                 }
         }
@@ -267,8 +271,8 @@ static void blk_trace_free(struct blk_trace *bt)
 {
         debugfs_remove(bt->msg_file);
         debugfs_remove(bt->dropped_file);
-        debugfs_remove(bt->dir);
         relay_close(bt->rchan);
+        debugfs_remove(bt->dir);
         free_percpu(bt->sequence);
         free_percpu(bt->msg_data);
         kfree(bt);
@@ -378,18 +382,8 @@ static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
 
 static int blk_remove_buf_file_callback(struct dentry *dentry)
 {
-        struct dentry *parent = dentry->d_parent;
         debugfs_remove(dentry);
 
-        /*
-        * this will fail for all but the last file, but that is ok. what we
-        * care about is the top level buts->name directory going away, when
-        * the last trace file is gone. Then we don't have to rmdir() that
-        * manually on trace stop, so it nicely solves the issue with
-        * force killing of running traces.
-        */
-
-        debugfs_remove(parent);
         return 0;
 }
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1993b7186cdb..8c804e24f96f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2222,7 +2222,11 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
         read++;
         cnt--;
 
-        if (!(iter->flags & ~FTRACE_ITER_CONT)) {
+        /*
+         * If the parser haven't finished with the last write,
+         * continue reading the user input without skipping spaces.
+         */
+        if (!(iter->flags & FTRACE_ITER_CONT)) {
                 /* skip white space */
                 while (cnt && isspace(ch)) {
                         ret = get_user(ch, ubuf++);
@@ -2232,8 +2236,9 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
                         cnt--;
                 }
 
+                /* only spaces were written */
                 if (isspace(ch)) {
-                        file->f_pos += read;
+                        *ppos += read;
                         ret = read;
                         goto out;
                 }
@@ -2262,12 +2267,12 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
                 if (ret)
                         goto out;
                 iter->buffer_idx = 0;
-        } else
+        } else {
                 iter->flags |= FTRACE_ITER_CONT;
+                iter->buffer[iter->buffer_idx++] = ch;
+        }
 
-
-        file->f_pos += read;
-
+        *ppos += read;
         ret = read;
  out:
         mutex_unlock(&ftrace_regex_lock);
diff --git a/kernel/trace/kmemtrace.c b/kernel/trace/kmemtrace.c
index dda53ccf749b..81b1645c8549 100644
--- a/kernel/trace/kmemtrace.c
+++ b/kernel/trace/kmemtrace.c
@@ -183,11 +183,9 @@ static void kmemtrace_stop_probes(void)
 
 static int kmem_trace_init(struct trace_array *tr)
 {
-        int cpu;
         kmemtrace_array = tr;
 
-        for_each_cpu(cpu, cpu_possible_mask)
-                tracing_reset(tr, cpu);
+        tracing_reset_online_cpus(tr);
 
         kmemtrace_start_probes();
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index da2c59d8f486..454e74e718cf 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -218,17 +218,12 @@ enum {
 
 static inline int rb_null_event(struct ring_buffer_event *event)
 {
-        return event->type_len == RINGBUF_TYPE_PADDING
-                        && event->time_delta == 0;
-}
-
-static inline int rb_discarded_event(struct ring_buffer_event *event)
-{
-        return event->type_len == RINGBUF_TYPE_PADDING && event->time_delta;
+        return event->type_len == RINGBUF_TYPE_PADDING && !event->time_delta;
 }
 
 static void rb_event_set_padding(struct ring_buffer_event *event)
 {
+        /* padding has a NULL time_delta */
         event->type_len = RINGBUF_TYPE_PADDING;
         event->time_delta = 0;
 }
@@ -472,14 +467,19 @@ struct ring_buffer_iter {
 };
 
 /* buffer may be either ring_buffer or ring_buffer_per_cpu */
-#define RB_WARN_ON(buffer, cond)                                \
-        ({                                                      \
-                int _____ret = unlikely(cond);                  \
-                if (_____ret) {                                 \
-                        atomic_inc(&buffer->record_disabled);   \
-                        WARN_ON(1);                             \
-                }                                               \
-                _____ret;                                       \
+#define RB_WARN_ON(b, cond)                                             \
+        ({                                                              \
+                int _____ret = unlikely(cond);                          \
+                if (_____ret) {                                         \
+                        if (__same_type(*(b), struct ring_buffer_per_cpu)) { \
+                                struct ring_buffer_per_cpu *__b =       \
+                                        (void *)b;                      \
+                                atomic_inc(&__b->buffer->record_disabled); \
+                        } else                                          \
+                                atomic_inc(&b->record_disabled);        \
+                        WARN_ON(1);                                     \
+                }                                                       \
+                _____ret;                                               \
         })
 
 /* Up this if you want to test the TIME_EXTENTS and normalization */
@@ -1778,9 +1778,6 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
         event->type_len = RINGBUF_TYPE_PADDING;
         /* time delta must be non zero */
         event->time_delta = 1;
-        /* Account for this as an entry */
-        local_inc(&tail_page->entries);
-        local_inc(&cpu_buffer->entries);
 
         /* Set write to end of buffer */
         length = (tail + length) - BUF_PAGE_SIZE;
@@ -2076,7 +2073,8 @@ static void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
 }
 
 static struct ring_buffer_event *
-rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
+rb_reserve_next_event(struct ring_buffer *buffer,
+                      struct ring_buffer_per_cpu *cpu_buffer,
                       unsigned long length)
 {
         struct ring_buffer_event *event;
@@ -2086,6 +2084,21 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
 
         rb_start_commit(cpu_buffer);
 
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
+        /*
+         * Due to the ability to swap a cpu buffer from a buffer
+         * it is possible it was swapped before we committed.
+         * (committing stops a swap). We check for it here and
+         * if it happened, we have to fail the write.
+         */
+        barrier();
+        if (unlikely(ACCESS_ONCE(cpu_buffer->buffer) != buffer)) {
+                local_dec(&cpu_buffer->committing);
+                local_dec(&cpu_buffer->commits);
+                return NULL;
+        }
+#endif
+
         length = rb_calculate_event_length(length);
  again:
         /*
@@ -2246,7 +2259,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
         if (length > BUF_MAX_DATA_SIZE)
                 goto out;
 
-        event = rb_reserve_next_event(cpu_buffer, length);
+        event = rb_reserve_next_event(buffer, cpu_buffer, length);
         if (!event)
                 goto out;
 
@@ -2269,18 +2282,23 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
 }
 EXPORT_SYMBOL_GPL(ring_buffer_lock_reserve);
 
-static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
+static void
+rb_update_write_stamp(struct ring_buffer_per_cpu *cpu_buffer,
                       struct ring_buffer_event *event)
 {
-        local_inc(&cpu_buffer->entries);
-
         /*
          * The event first in the commit queue updates the
          * time stamp.
          */
         if (rb_event_is_commit(cpu_buffer, event))
                 cpu_buffer->write_stamp += event->time_delta;
+}
 
+static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
+                      struct ring_buffer_event *event)
+{
+        local_inc(&cpu_buffer->entries);
+        rb_update_write_stamp(cpu_buffer, event);
         rb_end_commit(cpu_buffer);
 }
 
@@ -2327,32 +2345,57 @@ static inline void rb_event_discard(struct ring_buffer_event *event)
                 event->time_delta = 1;
 }
 
-/**
- * ring_buffer_event_discard - discard any event in the ring buffer
- * @event: the event to discard
- *
- * Sometimes a event that is in the ring buffer needs to be ignored.
- * This function lets the user discard an event in the ring buffer
- * and then that event will not be read later.
- *
- * Note, it is up to the user to be careful with this, and protect
- * against races. If the user discards an event that has been consumed
- * it is possible that it could corrupt the ring buffer.
+/*
+ * Decrement the entries to the page that an event is on.
+ * The event does not even need to exist, only the pointer
+ * to the page it is on. This may only be called before the commit
+ * takes place.
  */
-void ring_buffer_event_discard(struct ring_buffer_event *event)
+static inline void
+rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer,
+                   struct ring_buffer_event *event)
 {
-        rb_event_discard(event);
+        unsigned long addr = (unsigned long)event;
+        struct buffer_page *bpage = cpu_buffer->commit_page;
+        struct buffer_page *start;
+
+        addr &= PAGE_MASK;
+
+        /* Do the likely case first */
+        if (likely(bpage->page == (void *)addr)) {
+                local_dec(&bpage->entries);
+                return;
+        }
+
+        /*
+         * Because the commit page may be on the reader page we
+         * start with the next page and check the end loop there.
+         */
+        rb_inc_page(cpu_buffer, &bpage);
+        start = bpage;
+        do {
+                if (bpage->page == (void *)addr) {
+                        local_dec(&bpage->entries);
+                        return;
+                }
+                rb_inc_page(cpu_buffer, &bpage);
+        } while (bpage != start);
+
+        /* commit not part of this buffer?? */
+        RB_WARN_ON(cpu_buffer, 1);
 }
-EXPORT_SYMBOL_GPL(ring_buffer_event_discard);
 
 /**
  * ring_buffer_commit_discard - discard an event that has not been committed
  * @buffer: the ring buffer
  * @event: non committed event to discard
  *
- * This is similar to ring_buffer_event_discard but must only be
- * performed on an event that has not been committed yet. The difference
- * is that this will also try to free the event from the ring buffer
+ * Sometimes an event that is in the ring buffer needs to be ignored.
+ * This function lets the user discard an event in the ring buffer
+ * and then that event will not be read later.
+ *
+ * This function only works if it is called before the the item has been
+ * committed. It will try to free the event from the ring buffer
  * if another event has not been added behind it.
  *
  * If another event has been added behind it, it will set the event
@@ -2380,14 +2423,15 @@ void ring_buffer_discard_commit(struct ring_buffer *buffer,
          */
         RB_WARN_ON(buffer, !local_read(&cpu_buffer->committing));
 
+        rb_decrement_entry(cpu_buffer, event);
         if (rb_try_to_discard(cpu_buffer, event))
                 goto out;
 
         /*
          * The commit is still visible by the reader, so we
-         * must increment entries.
+         * must still update the timestamp.
          */
-        local_inc(&cpu_buffer->entries);
+        rb_update_write_stamp(cpu_buffer, event);
  out:
         rb_end_commit(cpu_buffer);
 
@@ -2448,7 +2492,7 @@ int ring_buffer_write(struct ring_buffer *buffer,
         if (length > BUF_MAX_DATA_SIZE)
                 goto out;
 
-        event = rb_reserve_next_event(cpu_buffer, length);
+        event = rb_reserve_next_event(buffer, cpu_buffer, length);
         if (!event)
                 goto out;
 
@@ -2899,8 +2943,7 @@ static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)
 
         event = rb_reader_event(cpu_buffer);
 
-        if (event->type_len <= RINGBUF_TYPE_DATA_TYPE_LEN_MAX
-                        || rb_discarded_event(event))
+        if (event->type_len <= RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
                 cpu_buffer->read++;
 
         rb_update_read_stamp(cpu_buffer, event);
@@ -3132,10 +3175,8 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
                 spin_unlock(&cpu_buffer->reader_lock);
         local_irq_restore(flags);
 
-        if (event && event->type_len == RINGBUF_TYPE_PADDING) {
-                cpu_relax();
+        if (event && event->type_len == RINGBUF_TYPE_PADDING)
                 goto again;
-        }
 
         return event;
 }
@@ -3160,10 +3201,8 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
         event = rb_iter_peek(iter, ts);
         spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
-        if (event && event->type_len == RINGBUF_TYPE_PADDING) {
-                cpu_relax();
+        if (event && event->type_len == RINGBUF_TYPE_PADDING)
                 goto again;
-        }
 
         return event;
 }
@@ -3209,10 +3248,8 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
  out:
         preempt_enable();
 
-        if (event && event->type_len == RINGBUF_TYPE_PADDING) {
-                cpu_relax();
+        if (event && event->type_len == RINGBUF_TYPE_PADDING)
                 goto again;
-        }
 
         return event;
 }
@@ -3292,21 +3329,19 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
         struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
         unsigned long flags;
 
- again:
         spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ again:
         event = rb_iter_peek(iter, ts);
         if (!event)
                 goto out;
 
+        if (event->type_len == RINGBUF_TYPE_PADDING)
+                goto again;
+
         rb_advance_iter(iter);
  out:
         spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
-        if (event && event->type_len == RINGBUF_TYPE_PADDING) {
-                cpu_relax();
-                goto again;
-        }
-
         return event;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_read);
@@ -3373,12 +3408,16 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
 
         spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 
+        if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing)))
+                goto out;
+
         __raw_spin_lock(&cpu_buffer->lock);
 
         rb_reset_cpu(cpu_buffer);
 
         __raw_spin_unlock(&cpu_buffer->lock);
 
+ out:
         spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
         atomic_dec(&cpu_buffer->record_disabled);
@@ -3461,6 +3500,7 @@ int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu)
 }
 EXPORT_SYMBOL_GPL(ring_buffer_empty_cpu);
 
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
 /**
  * ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers
  * @buffer_a: One buffer to swap with
@@ -3515,20 +3555,28 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
         atomic_inc(&cpu_buffer_a->record_disabled);
         atomic_inc(&cpu_buffer_b->record_disabled);
 
+        ret = -EBUSY;
+        if (local_read(&cpu_buffer_a->committing))
+                goto out_dec;
+        if (local_read(&cpu_buffer_b->committing))
+                goto out_dec;
+
         buffer_a->buffers[cpu] = cpu_buffer_b;
         buffer_b->buffers[cpu] = cpu_buffer_a;
 
         cpu_buffer_b->buffer = buffer_a;
         cpu_buffer_a->buffer = buffer_b;
 
+        ret = 0;
+
+out_dec:
         atomic_dec(&cpu_buffer_a->record_disabled);
         atomic_dec(&cpu_buffer_b->record_disabled);
-
-        ret = 0;
 out:
         return ret;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
+#endif /* CONFIG_RING_BUFFER_ALLOW_SWAP */
 
 /**
  * ring_buffer_alloc_read_page - allocate a page to read from buffer
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 63dbc7ff213f..5c75deeefe30 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -43,9 +43,6 @@
 
 #define TRACE_BUFFER_FLAGS      (RB_FL_OVERWRITE)
 
-unsigned long __read_mostly     tracing_max_latency;
-unsigned long __read_mostly     tracing_thresh;
-
 /*
  * On boot up, the ring buffer is set to the minimum size, so that
  * we do not waste memory on systems that are not using tracing.
@@ -172,10 +169,11 @@ static struct trace_array	global_trace;
 
 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
 
-int filter_current_check_discard(struct ftrace_event_call *call, void *rec,
+int filter_current_check_discard(struct ring_buffer *buffer,
+                                 struct ftrace_event_call *call, void *rec,
                                  struct ring_buffer_event *event)
 {
-        return filter_check_discard(call, rec, global_trace.buffer, event);
+        return filter_check_discard(call, rec, buffer, event);
 }
 EXPORT_SYMBOL_GPL(filter_current_check_discard);
 
@@ -266,6 +264,9 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
         TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
         TRACE_ITER_GRAPH_TIME;
 
+static int trace_stop_count;
+static DEFINE_SPINLOCK(tracing_start_lock);
+
 /**
  * trace_wake_up - wake up tasks waiting for trace input
  *
@@ -338,45 +339,6 @@ static struct {
 
 int trace_clock_id;
 
-/*
- * ftrace_max_lock is used to protect the swapping of buffers
- * when taking a max snapshot. The buffers themselves are
- * protected by per_cpu spinlocks. But the action of the swap
- * needs its own lock.
- *
- * This is defined as a raw_spinlock_t in order to help
- * with performance when lockdep debugging is enabled.
- */
-static raw_spinlock_t ftrace_max_lock =
-        (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
-
-/*
- * Copy the new maximum trace into the separate maximum-trace
- * structure. (this way the maximum trace is permanently saved,
- * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
- */
-static void
-__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
-{
-        struct trace_array_cpu *data = tr->data[cpu];
-
-        max_tr.cpu = cpu;
-        max_tr.time_start = data->preempt_timestamp;
-
-        data = max_tr.data[cpu];
-        data->saved_latency = tracing_max_latency;
-
-        memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
-        data->pid = tsk->pid;
-        data->uid = task_uid(tsk);
-        data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
-        data->policy = tsk->policy;
-        data->rt_priority = tsk->rt_priority;
-
-        /* record this tasks comm */
-        tracing_record_cmdline(tsk);
-}
-
 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
 {
         int len;
@@ -420,6 +382,56 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
         return cnt;
 }
 
+/*
+ * ftrace_max_lock is used to protect the swapping of buffers
+ * when taking a max snapshot. The buffers themselves are
+ * protected by per_cpu spinlocks. But the action of the swap
+ * needs its own lock.
+ *
+ * This is defined as a raw_spinlock_t in order to help
+ * with performance when lockdep debugging is enabled.
+ *
+ * It is also used in other places outside the update_max_tr
+ * so it needs to be defined outside of the
+ * CONFIG_TRACER_MAX_TRACE.
+ */
+static raw_spinlock_t ftrace_max_lock =
+        (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+unsigned long __read_mostly     tracing_max_latency;
+unsigned long __read_mostly     tracing_thresh;
+
+/*
+ * Copy the new maximum trace into the separate maximum-trace
+ * structure. (this way the maximum trace is permanently saved,
+ * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
+ */
+static void
+__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
+{
+        struct trace_array_cpu *data = tr->data[cpu];
+        struct trace_array_cpu *max_data = tr->data[cpu];
+
+        max_tr.cpu = cpu;
+        max_tr.time_start = data->preempt_timestamp;
+
+        max_data = max_tr.data[cpu];
+        max_data->saved_latency = tracing_max_latency;
+        max_data->critical_start = data->critical_start;
+        max_data->critical_end = data->critical_end;
+
+        memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
+        max_data->pid = tsk->pid;
+        max_data->uid = task_uid(tsk);
+        max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
+        max_data->policy = tsk->policy;
+        max_data->rt_priority = tsk->rt_priority;
+
+        /* record this tasks comm */
+        tracing_record_cmdline(tsk);
+}
+
 /**
  * update_max_tr - snapshot all trace buffers from global_trace to max_tr
  * @tr: tracer
@@ -434,16 +446,15 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
         struct ring_buffer *buf = tr->buffer;
 
+        if (trace_stop_count)
+                return;
+
         WARN_ON_ONCE(!irqs_disabled());
         __raw_spin_lock(&ftrace_max_lock);
 
         tr->buffer = max_tr.buffer;
         max_tr.buffer = buf;
 
-        ftrace_disable_cpu();
-        ring_buffer_reset(tr->buffer);
-        ftrace_enable_cpu();
-
         __update_max_tr(tr, tsk, cpu);
         __raw_spin_unlock(&ftrace_max_lock);
 }
@@ -461,21 +472,35 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
         int ret;
 
+        if (trace_stop_count)
+                return;
+
         WARN_ON_ONCE(!irqs_disabled());
         __raw_spin_lock(&ftrace_max_lock);
 
         ftrace_disable_cpu();
 
-        ring_buffer_reset(max_tr.buffer);
         ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
 
+        if (ret == -EBUSY) {
+                /*
+                 * We failed to swap the buffer due to a commit taking
+                 * place on this CPU. We fail to record, but we reset
+                 * the max trace buffer (no one writes directly to it)
+                 * and flag that it failed.
+                 */
+                trace_array_printk(&max_tr, _THIS_IP_,
+                        "Failed to swap buffers due to commit in progress\n");
+        }
+
         ftrace_enable_cpu();
 
-        WARN_ON_ONCE(ret && ret != -EAGAIN);
+        WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
 
         __update_max_tr(tr, tsk, cpu);
         __raw_spin_unlock(&ftrace_max_lock);
 }
+#endif /* CONFIG_TRACER_MAX_TRACE */
 
 /**
  * register_tracer - register a tracer with the ftrace system.
@@ -532,7 +557,6 @@ __acquires(kernel_lock)
         if (type->selftest && !tracing_selftest_disabled) {
                 struct tracer *saved_tracer = current_trace;
                 struct trace_array *tr = &global_trace;
-                int i;
 
                 /*
                  * Run a selftest on this tracer.
@@ -541,8 +565,7 @@ __acquires(kernel_lock)
                  * internal tracing to verify that everything is in order.
                  * If we fail, we do not register this tracer.
                  */
-                for_each_tracing_cpu(i)
-                        tracing_reset(tr, i);
+                tracing_reset_online_cpus(tr);
 
                 current_trace = type;
                 /* the test is responsible for initializing and enabling */
@@ -555,8 +578,7 @@ __acquires(kernel_lock)
                         goto out;
                 }
                 /* Only reset on passing, to avoid touching corrupted buffers */
-                for_each_tracing_cpu(i)
-                        tracing_reset(tr, i);
+                tracing_reset_online_cpus(tr);
 
                 printk(KERN_CONT "PASSED\n");
         }
@@ -631,21 +653,42 @@ void unregister_tracer(struct tracer *type)
         mutex_unlock(&trace_types_lock);
 }
 
-void tracing_reset(struct trace_array *tr, int cpu)
+static void __tracing_reset(struct trace_array *tr, int cpu)
 {
         ftrace_disable_cpu();
         ring_buffer_reset_cpu(tr->buffer, cpu);
         ftrace_enable_cpu();
 }
 
+void tracing_reset(struct trace_array *tr, int cpu)
+{
+        struct ring_buffer *buffer = tr->buffer;
+
+        ring_buffer_record_disable(buffer);
+
+        /* Make sure all commits have finished */
+        synchronize_sched();
+        __tracing_reset(tr, cpu);
+
+        ring_buffer_record_enable(buffer);
+}
+
 void tracing_reset_online_cpus(struct trace_array *tr)
 {
+        struct ring_buffer *buffer = tr->buffer;
         int cpu;
 
+        ring_buffer_record_disable(buffer);
+
+        /* Make sure all commits have finished */
+        synchronize_sched();
+
         tr->time_start = ftrace_now(tr->cpu);
 
         for_each_online_cpu(cpu)
-                tracing_reset(tr, cpu);
+                __tracing_reset(tr, cpu);
+
+        ring_buffer_record_enable(buffer);
 }
 
 void tracing_reset_current(int cpu)
@@ -676,9 +719,6 @@ static void trace_init_cmdlines(void)
         cmdline_idx = 0;
 }
 
-static int trace_stop_count;
-static DEFINE_SPINLOCK(tracing_start_lock);
-
 /**
  * ftrace_off_permanent - disable all ftrace code permanently
  *
@@ -859,14 +899,15 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
 }
 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
 
-struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
-                                                    int type,
-                                                    unsigned long len,
-                                                    unsigned long flags, int pc)
+struct ring_buffer_event *
+trace_buffer_lock_reserve(struct ring_buffer *buffer,
+                          int type,
+                          unsigned long len,
+                          unsigned long flags, int pc)
 {
         struct ring_buffer_event *event;
 
-        event = ring_buffer_lock_reserve(tr->buffer, len);
+        event = ring_buffer_lock_reserve(buffer, len);
         if (event != NULL) {
                 struct trace_entry *ent = ring_buffer_event_data(event);
 
@@ -877,53 +918,59 @@ struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
         return event;
 }
 
-static inline void __trace_buffer_unlock_commit(struct trace_array *tr,
-                                        struct ring_buffer_event *event,
-                                        unsigned long flags, int pc,
-                                        int wake)
+static inline void
+__trace_buffer_unlock_commit(struct ring_buffer *buffer,
+                             struct ring_buffer_event *event,
+                             unsigned long flags, int pc,
+                             int wake)
 {
-        ring_buffer_unlock_commit(tr->buffer, event);
+        ring_buffer_unlock_commit(buffer, event);
 
-        ftrace_trace_stack(tr, flags, 6, pc);
-        ftrace_trace_userstack(tr, flags, pc);
+        ftrace_trace_stack(buffer, flags, 6, pc);
+        ftrace_trace_userstack(buffer, flags, pc);
 
         if (wake)
                 trace_wake_up();
 }
 
-void trace_buffer_unlock_commit(struct trace_array *tr,
-                                        struct ring_buffer_event *event,
-                                        unsigned long flags, int pc)
+void trace_buffer_unlock_commit(struct ring_buffer *buffer,
+                                struct ring_buffer_event *event,
+                                unsigned long flags, int pc)
 {
-        __trace_buffer_unlock_commit(tr, event, flags, pc, 1);
+        __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
 }
 
 struct ring_buffer_event *
-trace_current_buffer_lock_reserve(int type, unsigned long len,
+trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
+                                  int type, unsigned long len,
                                   unsigned long flags, int pc)
 {
-        return trace_buffer_lock_reserve(&global_trace,
+        *current_rb = global_trace.buffer;
+        return trace_buffer_lock_reserve(*current_rb,
                                          type, len, flags, pc);
 }
 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
 
-void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
+void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
+                                        struct ring_buffer_event *event,
                                         unsigned long flags, int pc)
 {
-        __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 1);
+        __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
 }
 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
 
-void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event,
-                                        unsigned long flags, int pc)
+void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
+                                       struct ring_buffer_event *event,
+                                       unsigned long flags, int pc)
 {
-        __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 0);
+        __trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
 }
 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
 
-void trace_current_buffer_discard_commit(struct ring_buffer_event *event)
+void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
+                                         struct ring_buffer_event *event)
 {
-        ring_buffer_discard_commit(global_trace.buffer, event);
+        ring_buffer_discard_commit(buffer, event);
 }
 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
 
@@ -933,6 +980,7 @@ trace_function(struct trace_array *tr,
                int pc)
 {
         struct ftrace_event_call *call = &event_function;
+        struct ring_buffer *buffer = tr->buffer;
         struct ring_buffer_event *event;
         struct ftrace_entry *entry;
 
@@ -940,7 +988,7 @@ trace_function(struct trace_array *tr,
         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                 return;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
+        event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
                                           flags, pc);
         if (!event)
                 return;
@@ -948,8 +996,8 @@ trace_function(struct trace_array *tr,
         entry->ip                       = ip;
         entry->parent_ip                = parent_ip;
 
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, buffer, event))
+                ring_buffer_unlock_commit(buffer, event);
 }
 
 void
@@ -962,7 +1010,7 @@ ftrace(struct trace_array *tr, struct trace_array_cpu *data,
 }
 
 #ifdef CONFIG_STACKTRACE
-static void __ftrace_trace_stack(struct trace_array *tr,
+static void __ftrace_trace_stack(struct ring_buffer *buffer,
                                  unsigned long flags,
                                  int skip, int pc)
 {
@@ -971,7 +1019,7 @@ static void __ftrace_trace_stack(struct trace_array *tr,
         struct stack_entry *entry;
         struct stack_trace trace;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_STACK,
+        event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
                                           sizeof(*entry), flags, pc);
         if (!event)
                 return;
@@ -984,26 +1032,27 @@ static void __ftrace_trace_stack(struct trace_array *tr,
         trace.entries           = entry->caller;
 
         save_stack_trace(&trace);
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, buffer, event))
+                ring_buffer_unlock_commit(buffer, event);
 }
 
-void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, int skip,
-                        int pc)
+void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
+                        int skip, int pc)
 {
         if (!(trace_flags & TRACE_ITER_STACKTRACE))
                 return;
 
-        __ftrace_trace_stack(tr, flags, skip, pc);
+        __ftrace_trace_stack(buffer, flags, skip, pc);
 }
 
 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
                    int pc)
 {
-        __ftrace_trace_stack(tr, flags, skip, pc);
+        __ftrace_trace_stack(tr->buffer, flags, skip, pc);
 }
 
-void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc)
+void
+ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 {
         struct ftrace_event_call *call = &event_user_stack;
         struct ring_buffer_event *event;
@@ -1013,7 +1062,7 @@ void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc)
         if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
                 return;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
+        event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
                                           sizeof(*entry), flags, pc);
         if (!event)
                 return;
@@ -1027,8 +1076,8 @@ void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc)
         trace.entries           = entry->caller;
 
         save_stack_trace_user(&trace);
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, buffer, event))
+                ring_buffer_unlock_commit(buffer, event);
 }
 
 #ifdef UNUSED
@@ -1047,9 +1096,10 @@ ftrace_trace_special(void *__tr,
 {
         struct ring_buffer_event *event;
         struct trace_array *tr = __tr;
+        struct ring_buffer *buffer = tr->buffer;
         struct special_entry *entry;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
+        event = trace_buffer_lock_reserve(buffer, TRACE_SPECIAL,
                                           sizeof(*entry), 0, pc);
         if (!event)
                 return;
@@ -1057,7 +1107,7 @@ ftrace_trace_special(void *__tr,
         entry->arg1                     = arg1;
         entry->arg2                     = arg2;
         entry->arg3                     = arg3;
-        trace_buffer_unlock_commit(tr, event, 0, pc);
+        trace_buffer_unlock_commit(buffer, event, 0, pc);
 }
 
 void
@@ -1103,6 +1153,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 
         struct ftrace_event_call *call = &event_bprint;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         struct trace_array *tr = &global_trace;
         struct trace_array_cpu *data;
         struct bprint_entry *entry;
@@ -1135,7 +1186,9 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
                 goto out_unlock;
 
         size = sizeof(*entry) + sizeof(u32) * len;
-        event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc);
+        buffer = tr->buffer;
+        event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
+                                          flags, pc);
         if (!event)
                 goto out_unlock;
         entry = ring_buffer_event_data(event);
@@ -1143,8 +1196,8 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
         entry->fmt                      = fmt;
 
         memcpy(entry->buf, trace_buf, sizeof(u32) * len);
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, buffer, event))
+                ring_buffer_unlock_commit(buffer, event);
 
 out_unlock:
         __raw_spin_unlock(&trace_buf_lock);
@@ -1159,14 +1212,30 @@ out:
 }
 EXPORT_SYMBOL_GPL(trace_vbprintk);
 
-int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
+int trace_array_printk(struct trace_array *tr,
+                       unsigned long ip, const char *fmt, ...)
+{
+        int ret;
+        va_list ap;
+
+        if (!(trace_flags & TRACE_ITER_PRINTK))
+                return 0;
+
+        va_start(ap, fmt);
+        ret = trace_array_vprintk(tr, ip, fmt, ap);
+        va_end(ap);
+        return ret;
+}
+
+int trace_array_vprintk(struct trace_array *tr,
+                        unsigned long ip, const char *fmt, va_list args)
 {
         static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
         static char trace_buf[TRACE_BUF_SIZE];
 
         struct ftrace_event_call *call = &event_print;
         struct ring_buffer_event *event;
-        struct trace_array *tr = &global_trace;
+        struct ring_buffer *buffer;
         struct trace_array_cpu *data;
         int cpu, len = 0, size, pc;
         struct print_entry *entry;
@@ -1194,7 +1263,9 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
         trace_buf[len] = 0;
 
         size = sizeof(*entry) + len + 1;
-        event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
+        buffer = tr->buffer;
+        event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+                                          irq_flags, pc);
         if (!event)
                 goto out_unlock;
         entry = ring_buffer_event_data(event);
@@ -1202,8 +1273,8 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 
         memcpy(&entry->buf, trace_buf, len);
         entry->buf[len] = 0;
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, buffer, event))
+                ring_buffer_unlock_commit(buffer, event);
 
  out_unlock:
         __raw_spin_unlock(&trace_buf_lock);
@@ -1215,6 +1286,11 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 
         return len;
 }
+
+int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
+{
+        return trace_array_printk(&global_trace, ip, fmt, args);
+}
 EXPORT_SYMBOL_GPL(trace_vprintk);
 
 enum trace_file_type {
@@ -1354,6 +1430,37 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos)
         return ent;
 }
 
+static void tracing_iter_reset(struct trace_iterator *iter, int cpu)
+{
+        struct trace_array *tr = iter->tr;
+        struct ring_buffer_event *event;
+        struct ring_buffer_iter *buf_iter;
+        unsigned long entries = 0;
+        u64 ts;
+
+        tr->data[cpu]->skipped_entries = 0;
+
+        if (!iter->buffer_iter[cpu])
+                return;
+
+        buf_iter = iter->buffer_iter[cpu];
+        ring_buffer_iter_reset(buf_iter);
+
+        /*
+         * We could have the case with the max latency tracers
+         * that a reset never took place on a cpu. This is evident
+         * by the timestamp being before the start of the buffer.
+         */
+        while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
+                if (ts >= iter->tr->time_start)
+                        break;
+                entries++;
+                ring_buffer_read(buf_iter, NULL);
+        }
+
+        tr->data[cpu]->skipped_entries = entries;
+}
+
 /*
  * No necessary locking here. The worst thing which can
  * happen is loosing events consumed at the same time
@@ -1392,10 +1499,9 @@ static void *s_start(struct seq_file *m, loff_t *pos)
 
                 if (cpu_file == TRACE_PIPE_ALL_CPU) {
                         for_each_tracing_cpu(cpu)
-                                ring_buffer_iter_reset(iter->buffer_iter[cpu]);
+                                tracing_iter_reset(iter, cpu);
                 } else
-                        ring_buffer_iter_reset(iter->buffer_iter[cpu_file]);
-
+                        tracing_iter_reset(iter, cpu_file);
 
                 ftrace_enable_cpu();
 
@@ -1444,16 +1550,32 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter)
         struct trace_array *tr = iter->tr;
         struct trace_array_cpu *data = tr->data[tr->cpu];
         struct tracer *type = current_trace;
-        unsigned long total;
-        unsigned long entries;
+        unsigned long entries = 0;
+        unsigned long total = 0;
+        unsigned long count;
         const char *name = "preemption";
+        int cpu;
 
         if (type)
                 name = type->name;
 
-        entries = ring_buffer_entries(iter->tr->buffer);
-        total = entries +
-                ring_buffer_overruns(iter->tr->buffer);
+
+        for_each_tracing_cpu(cpu) {
+                count = ring_buffer_entries_cpu(tr->buffer, cpu);
+                /*
+                 * If this buffer has skipped entries, then we hold all
+                 * entries for the trace and we need to ignore the
+                 * ones before the time stamp.
+                 */
+                if (tr->data[cpu]->skipped_entries) {
+                        count -= tr->data[cpu]->skipped_entries;
+                        /* total is the same as the entries */
+                        total += count;
+                } else
+                        total += count +
+                                ring_buffer_overrun_cpu(tr->buffer, cpu);
+                entries += count;
+        }
 
         seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
                    name, UTS_RELEASE);
@@ -1495,7 +1617,7 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter)
                 seq_puts(m, "\n#  => ended at:   ");
                 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
                 trace_print_seq(m, &iter->seq);
-                seq_puts(m, "#\n");
+                seq_puts(m, "\n#\n");
         }
 
         seq_puts(m, "#\n");
@@ -1514,6 +1636,9 @@ static void test_cpu_buff_start(struct trace_iterator *iter)
         if (cpumask_test_cpu(iter->cpu, iter->started))
                 return;
 
+        if (iter->tr->data[iter->cpu]->skipped_entries)
+                return;
+
         cpumask_set_cpu(iter->cpu, iter->started);
 
         /* Don't print started cpu buffer for the first entry of the trace */
@@ -1776,19 +1901,23 @@ __tracing_open(struct inode *inode, struct file *file)
         if (ring_buffer_overruns(iter->tr->buffer))
                 iter->iter_flags |= TRACE_FILE_ANNOTATE;
 
+        /* stop the trace while dumping */
+        tracing_stop();
+
         if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
                 for_each_tracing_cpu(cpu) {
 
                         iter->buffer_iter[cpu] =
                                 ring_buffer_read_start(iter->tr->buffer, cpu);
+                        tracing_iter_reset(iter, cpu);
                 }
         } else {
                 cpu = iter->cpu_file;
                 iter->buffer_iter[cpu] =
                                 ring_buffer_read_start(iter->tr->buffer, cpu);
+                tracing_iter_reset(iter, cpu);
         }
 
-        /* TODO stop tracer */
         ret = seq_open(file, &tracer_seq_ops);
         if (ret < 0) {
                 fail_ret = ERR_PTR(ret);
@@ -1798,9 +1927,6 @@ __tracing_open(struct inode *inode, struct file *file)
         m = file->private_data;
         m->private = iter;
 
-        /* stop the trace while dumping */
-        tracing_stop();
-
         mutex_unlock(&trace_types_lock);
 
         return iter;
@@ -1811,6 +1937,7 @@ __tracing_open(struct inode *inode, struct file *file)
                         ring_buffer_read_finish(iter->buffer_iter[cpu]);
         }
         free_cpumask_var(iter->started);
+        tracing_start();
  fail:
         mutex_unlock(&trace_types_lock);
         kfree(iter->trace);
@@ -3774,17 +3901,9 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
         if (ret < 0)
                 return ret;
 
-        switch (val) {
-        case 0:
-                trace_flags &= ~(1 << index);
-                break;
-        case 1:
-                trace_flags |= 1 << index;
-                break;
-
-        default:
+        if (val != 0 && val != 1)
                 return -EINVAL;
-        }
+        set_tracer_flags(1 << index, val);
 
         *ppos += cnt;
 
@@ -3952,11 +4071,13 @@ static __init int tracer_init_debugfs(void)
         trace_create_file("current_tracer", 0644, d_tracer,
                         &global_trace, &set_tracer_fops);
 
+#ifdef CONFIG_TRACER_MAX_TRACE
         trace_create_file("tracing_max_latency", 0644, d_tracer,
                         &tracing_max_latency, &tracing_max_lat_fops);
 
         trace_create_file("tracing_thresh", 0644, d_tracer,
                         &tracing_thresh, &tracing_max_lat_fops);
+#endif
 
         trace_create_file("README", 0444, d_tracer,
                         NULL, &tracing_readme_fops);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f5362a0529eb..821064914c80 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -258,9 +258,6 @@ struct trace_array_cpu {
         atomic_t                disabled;
         void                    *buffer_page;   /* ring buffer spare */
 
-        /* these fields get copied into max-trace: */
-        unsigned long           trace_idx;
-        unsigned long           overrun;
         unsigned long           saved_latency;
         unsigned long           critical_start;
         unsigned long           critical_end;
@@ -268,6 +265,7 @@ struct trace_array_cpu {
         unsigned long           nice;
         unsigned long           policy;
         unsigned long           rt_priority;
+        unsigned long           skipped_entries;
         cycle_t                 preempt_timestamp;
         pid_t                   pid;
         uid_t                   uid;
@@ -441,12 +439,13 @@ void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
 
 struct ring_buffer_event;
 
-struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
-                                                    int type,
-                                                    unsigned long len,
-                                                    unsigned long flags,
-                                                    int pc);
-void trace_buffer_unlock_commit(struct trace_array *tr,
+struct ring_buffer_event *
+trace_buffer_lock_reserve(struct ring_buffer *buffer,
+                          int type,
+                          unsigned long len,
+                          unsigned long flags,
+                          int pc);
+void trace_buffer_unlock_commit(struct ring_buffer *buffer,
                                 struct ring_buffer_event *event,
                                 unsigned long flags, int pc);
 
@@ -497,18 +496,20 @@ void unregister_tracer(struct tracer *type);
 
 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 
+#ifdef CONFIG_TRACER_MAX_TRACE
 extern unsigned long tracing_max_latency;
 extern unsigned long tracing_thresh;
 
 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
 void update_max_tr_single(struct trace_array *tr,
                           struct task_struct *tsk, int cpu);
+#endif /* CONFIG_TRACER_MAX_TRACE */
 
 #ifdef CONFIG_STACKTRACE
-void ftrace_trace_stack(struct trace_array *tr, unsigned long flags,
+void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
                         int skip, int pc);
 
-void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags,
+void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
                             int pc);
 
 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
@@ -589,6 +590,11 @@ extern int
 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
 extern int
 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
+extern int
+trace_array_vprintk(struct trace_array *tr,
+                    unsigned long ip, const char *fmt, va_list args);
+int trace_array_printk(struct trace_array *tr,
+                       unsigned long ip, const char *fmt, ...);
 
 extern unsigned long trace_flags;
 
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index a29ef23ffb47..19bfc75d467e 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -41,14 +41,12 @@ void disable_boot_trace(void)
 
 static int boot_trace_init(struct trace_array *tr)
 {
-        int cpu;
         boot_trace = tr;
 
         if (!tr)
                 return 0;
 
-        for_each_cpu(cpu, cpu_possible_mask)
-                tracing_reset(tr, cpu);
+        tracing_reset_online_cpus(tr);
 
         tracing_sched_switch_assign_trace(tr);
         return 0;
@@ -132,6 +130,7 @@ struct tracer boot_tracer __read_mostly =
 void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
 {
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         struct trace_boot_call *entry;
         struct trace_array *tr = boot_trace;
 
@@ -144,13 +143,14 @@ void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
         sprint_symbol(bt->func, (unsigned long)fn);
         preempt_disable();
 
-        event = trace_buffer_lock_reserve(tr, TRACE_BOOT_CALL,
+        buffer = tr->buffer;
+        event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_CALL,
                                           sizeof(*entry), 0, 0);
         if (!event)
                 goto out;
         entry   = ring_buffer_event_data(event);
         entry->boot_call = *bt;
-        trace_buffer_unlock_commit(tr, event, 0, 0);
+        trace_buffer_unlock_commit(buffer, event, 0, 0);
  out:
         preempt_enable();
 }
@@ -158,6 +158,7 @@ void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
 void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn)
 {
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         struct trace_boot_ret *entry;
         struct trace_array *tr = boot_trace;
 
@@ -167,13 +168,14 @@ void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn)
         sprint_symbol(bt->func, (unsigned long)fn);
         preempt_disable();
 
-        event = trace_buffer_lock_reserve(tr, TRACE_BOOT_RET,
+        buffer = tr->buffer;
+        event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_RET,
                                           sizeof(*entry), 0, 0);
         if (!event)
                 goto out;
         entry   = ring_buffer_event_data(event);
         entry->boot_ret = *bt;
-        trace_buffer_unlock_commit(tr, event, 0, 0);
+        trace_buffer_unlock_commit(buffer, event, 0, 0);
  out:
         preempt_enable();
 }
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 197cdaa96c43..ba3492076ab2 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1485,6 +1485,7 @@ static void
 function_test_events_call(unsigned long ip, unsigned long parent_ip)
 {
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         struct ftrace_entry *entry;
         unsigned long flags;
         long disabled;
@@ -1502,7 +1503,8 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip)
 
         local_save_flags(flags);
 
-        event = trace_current_buffer_lock_reserve(TRACE_FN, sizeof(*entry),
+        event = trace_current_buffer_lock_reserve(&buffer,
+                                                  TRACE_FN, sizeof(*entry),
                                                   flags, pc);
         if (!event)
                 goto out;
@@ -1510,7 +1512,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip)
         entry->ip                       = ip;
         entry->parent_ip                = parent_ip;
 
-        trace_nowake_buffer_unlock_commit(event, flags, pc);
+        trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
 
  out:
         atomic_dec(&per_cpu(test_event_disable, cpu));
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 9f03082c81d8..93660fbbf629 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -309,7 +309,7 @@ void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
         struct event_filter *filter = call->filter;
 
         mutex_lock(&event_mutex);
-        if (filter->filter_string)
+        if (filter && filter->filter_string)
                 trace_seq_printf(s, "%s\n", filter->filter_string);
         else
                 trace_seq_printf(s, "none\n");
@@ -322,7 +322,7 @@ void print_subsystem_event_filter(struct event_subsystem *system,
         struct event_filter *filter = system->filter;
 
         mutex_lock(&event_mutex);
-        if (filter->filter_string)
+        if (filter && filter->filter_string)
                 trace_seq_printf(s, "%s\n", filter->filter_string);
         else
                 trace_seq_printf(s, "none\n");
@@ -390,6 +390,9 @@ void destroy_preds(struct ftrace_event_call *call)
         struct event_filter *filter = call->filter;
         int i;
 
+        if (!filter)
+                return;
+
         for (i = 0; i < MAX_FILTER_PRED; i++) {
                 if (filter->preds[i])
                         filter_free_pred(filter->preds[i]);
@@ -400,17 +403,19 @@ void destroy_preds(struct ftrace_event_call *call)
         call->filter = NULL;
 }
 
-int init_preds(struct ftrace_event_call *call)
+static int init_preds(struct ftrace_event_call *call)
 {
         struct event_filter *filter;
         struct filter_pred *pred;
         int i;
 
+        if (call->filter)
+                return 0;
+
         filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
         if (!call->filter)
                 return -ENOMEM;
 
-        call->filter_active = 0;
         filter->n_preds = 0;
 
         filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
@@ -432,7 +437,26 @@ oom:
 
         return -ENOMEM;
 }
-EXPORT_SYMBOL_GPL(init_preds);
+
+static int init_subsystem_preds(struct event_subsystem *system)
+{
+        struct ftrace_event_call *call;
+        int err;
+
+        list_for_each_entry(call, &ftrace_events, list) {
+                if (!call->define_fields)
+                        continue;
+
+                if (strcmp(call->system, system->name) != 0)
+                        continue;
+
+                err = init_preds(call);
+                if (err)
+                        return err;
+        }
+
+        return 0;
+}
 
 enum {
         FILTER_DISABLE_ALL,
@@ -449,6 +473,9 @@ static void filter_free_subsystem_preds(struct event_subsystem *system,
                 if (!call->define_fields)
                         continue;
 
+                if (strcmp(call->system, system->name) != 0)
+                        continue;
+
                 if (flag == FILTER_INIT_NO_RESET) {
                         call->filter->no_reset = false;
                         continue;
@@ -457,10 +484,8 @@ static void filter_free_subsystem_preds(struct event_subsystem *system,
                 if (flag == FILTER_SKIP_NO_RESET && call->filter->no_reset)
                         continue;
 
-                if (!strcmp(call->system, system->name)) {
-                        filter_disable_preds(call);
-                        remove_filter_string(call->filter);
-                }
+                filter_disable_preds(call);
+                remove_filter_string(call->filter);
         }
 }
 
@@ -1094,6 +1119,10 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
 
         mutex_lock(&event_mutex);
 
+        err = init_preds(call);
+        if (err)
+                goto out_unlock;
+
         if (!strcmp(strstrip(filter_string), "0")) {
                 filter_disable_preds(call);
                 remove_filter_string(call->filter);
@@ -1139,6 +1168,10 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
 
         mutex_lock(&event_mutex);
 
+        err = init_subsystem_preds(system);
+        if (err)
+                goto out_unlock;
+
         if (!strcmp(strstrip(filter_string), "0")) {
                 filter_free_subsystem_preds(system, FILTER_DISABLE_ALL);
                 remove_filter_string(system->filter);
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index f75faeccf68e..a79ef6f193c0 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -120,7 +120,7 @@ ftrace_format_##call(struct ftrace_event_call *unused,			\
 static int ftrace_raw_init_event(struct ftrace_event_call *event_call)
 {
         INIT_LIST_HEAD(&event_call->fields);
-        init_preds(event_call);
+
         return 0;
 }
 
@@ -137,7 +137,7 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
         .raw_init               = ftrace_raw_init_event,                \
         .show_format            = ftrace_format_##call,                 \
         .define_fields          = ftrace_define_fields_##call,          \
-};
+};                                                                      \
 
 #undef TRACE_EVENT_FORMAT_NOFILTER
 #define TRACE_EVENT_FORMAT_NOFILTER(call, proto, args, fmt, tstruct,    \
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 3f4a251b7d16..b3749a2c3132 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -173,19 +173,20 @@ static int __trace_graph_entry(struct trace_array *tr,
 {
         struct ftrace_event_call *call = &event_funcgraph_entry;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer = tr->buffer;
         struct ftrace_graph_ent_entry *entry;
 
         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                 return 0;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_GRAPH_ENT,
+        event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
                                           sizeof(*entry), flags, pc);
         if (!event)
                 return 0;
         entry   = ring_buffer_event_data(event);
         entry->graph_ent                        = *trace;
-        if (!filter_current_check_discard(call, entry, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_current_check_discard(buffer, call, entry, event))
+                ring_buffer_unlock_commit(buffer, event);
 
         return 1;
 }
@@ -236,19 +237,20 @@ static void __trace_graph_return(struct trace_array *tr,
 {
         struct ftrace_event_call *call = &event_funcgraph_exit;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer = tr->buffer;
         struct ftrace_graph_ret_entry *entry;
 
         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                 return;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_GRAPH_RET,
+        event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
                                           sizeof(*entry), flags, pc);
         if (!event)
                 return;
         entry   = ring_buffer_event_data(event);
         entry->ret                              = *trace;
-        if (!filter_current_check_discard(call, entry, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_current_check_discard(buffer, call, entry, event))
+                ring_buffer_unlock_commit(buffer, event);
 }
 
 void trace_graph_return(struct ftrace_graph_ret *trace)
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index b923d13e2fad..5555b75a0d12 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -178,7 +178,6 @@ out_unlock:
 out:
         data->critical_sequence = max_sequence;
         data->preempt_timestamp = ftrace_now(cpu);
-        tracing_reset(tr, cpu);
         trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 }
 
@@ -208,7 +207,6 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
         data->critical_sequence = max_sequence;
         data->preempt_timestamp = ftrace_now(cpu);
         data->critical_start = parent_ip ? : ip;
-        tracing_reset(tr, cpu);
 
         local_save_flags(flags);
 
@@ -379,6 +377,7 @@ static void __irqsoff_tracer_init(struct trace_array *tr)
         irqsoff_trace = tr;
         /* make sure that the tracer is visible */
         smp_wmb();
+        tracing_reset_online_cpus(tr);
         start_irqsoff_tracer(tr);
 }
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index f4ec3fc87b2d..19a6de63b44b 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -819,6 +819,7 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
         struct trace_probe *tp = container_of(kp, struct trace_probe, kp);
         struct kprobe_trace_entry *entry;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         int size, i, pc;
         unsigned long irq_flags;
         struct ftrace_event_call *call = &tp->call;
@@ -830,7 +831,7 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 
         size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
 
-        event = trace_current_buffer_lock_reserve(call->id, size,
+        event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
                                                   irq_flags, pc);
         if (!event)
                 return 0;
@@ -841,8 +842,8 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
         for (i = 0; i < tp->nr_args; i++)
                 entry->args[i] = call_fetch(&tp->args[i], regs);
 
-        if (!filter_current_check_discard(call, entry, event))
-                trace_nowake_buffer_unlock_commit(event, irq_flags, pc);
+        if (!filter_current_check_discard(buffer, call, entry, event))
+                trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
         return 0;
 }
 
@@ -853,6 +854,7 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
         struct kretprobe_trace_entry *entry;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         int size, i, pc;
         unsigned long irq_flags;
         struct ftrace_event_call *call = &tp->call;
@@ -862,7 +864,7 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
 
         size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
 
-        event = trace_current_buffer_lock_reserve(call->id, size,
+        event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
                                                   irq_flags, pc);
         if (!event)
                 return 0;
@@ -874,8 +876,8 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
         for (i = 0; i < tp->nr_args; i++)
                 entry->args[i] = call_fetch(&tp->args[i], regs);
 
-        if (!filter_current_check_discard(call, entry, event))
-                trace_nowake_buffer_unlock_commit(event, irq_flags, pc);
+        if (!filter_current_check_discard(buffer, call, entry, event))
+                trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 
         return 0;
 }
@@ -964,7 +966,7 @@ static void probe_event_disable(struct ftrace_event_call *call)
 static int probe_event_raw_init(struct ftrace_event_call *event_call)
 {
         INIT_LIST_HEAD(&event_call->fields);
-        init_preds(event_call);
+
         return 0;
 }
 
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index d53b45ed0806..c4c9bbda53d3 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -307,11 +307,12 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
                                 struct trace_array_cpu *data,
                                 struct mmiotrace_rw *rw)
 {
+        struct ring_buffer *buffer = tr->buffer;
         struct ring_buffer_event *event;
         struct trace_mmiotrace_rw *entry;
         int pc = preempt_count();
 
-        event = trace_buffer_lock_reserve(tr, TRACE_MMIO_RW,
+        event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
                                           sizeof(*entry), 0, pc);
         if (!event) {
                 atomic_inc(&dropped_count);
@@ -319,7 +320,7 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
         }
         entry   = ring_buffer_event_data(event);
         entry->rw                       = *rw;
-        trace_buffer_unlock_commit(tr, event, 0, pc);
+        trace_buffer_unlock_commit(buffer, event, 0, pc);
 }
 
 void mmio_trace_rw(struct mmiotrace_rw *rw)
@@ -333,11 +334,12 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
                                 struct trace_array_cpu *data,
                                 struct mmiotrace_map *map)
 {
+        struct ring_buffer *buffer = tr->buffer;
         struct ring_buffer_event *event;
         struct trace_mmiotrace_map *entry;
         int pc = preempt_count();
 
-        event = trace_buffer_lock_reserve(tr, TRACE_MMIO_MAP,
+        event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
                                           sizeof(*entry), 0, pc);
         if (!event) {
                 atomic_inc(&dropped_count);
@@ -345,7 +347,7 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
         }
         entry   = ring_buffer_event_data(event);
         entry->map                      = *map;
-        trace_buffer_unlock_commit(tr, event, 0, pc);
+        trace_buffer_unlock_commit(buffer, event, 0, pc);
 }
 
 void mmio_trace_mapping(struct mmiotrace_map *map)
diff --git a/kernel/trace/trace_power.c b/kernel/trace/trace_power.c
index 8a30d9874cd4..fe1a00f1445a 100644
--- a/kernel/trace/trace_power.c
+++ b/kernel/trace/trace_power.c
@@ -38,6 +38,7 @@ static void probe_power_end(struct power_trace *it)
 {
         struct ftrace_event_call *call = &event_power;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         struct trace_power *entry;
         struct trace_array_cpu *data;
         struct trace_array *tr = power_trace;
@@ -45,18 +46,20 @@ static void probe_power_end(struct power_trace *it)
         if (!trace_power_enabled)
                 return;
 
+        buffer = tr->buffer;
+
         preempt_disable();
         it->end = ktime_get();
         data = tr->data[smp_processor_id()];
 
-        event = trace_buffer_lock_reserve(tr, TRACE_POWER,
+        event = trace_buffer_lock_reserve(buffer, TRACE_POWER,
                                           sizeof(*entry), 0, 0);
         if (!event)
                 goto out;
         entry   = ring_buffer_event_data(event);
         entry->state_data = *it;
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                trace_buffer_unlock_commit(tr, event, 0, 0);
+        if (!filter_check_discard(call, entry, buffer, event))
+                trace_buffer_unlock_commit(buffer, event, 0, 0);
  out:
         preempt_enable();
 }
@@ -66,6 +69,7 @@ static void probe_power_mark(struct power_trace *it, unsigned int type,
 {
         struct ftrace_event_call *call = &event_power;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         struct trace_power *entry;
         struct trace_array_cpu *data;
         struct trace_array *tr = power_trace;
@@ -73,6 +77,8 @@ static void probe_power_mark(struct power_trace *it, unsigned int type,
         if (!trace_power_enabled)
                 return;
 
+        buffer = tr->buffer;
+
         memset(it, 0, sizeof(struct power_trace));
         it->state = level;
         it->type = type;
@@ -81,14 +87,14 @@ static void probe_power_mark(struct power_trace *it, unsigned int type,
         it->end = it->stamp;
         data = tr->data[smp_processor_id()];
 
-        event = trace_buffer_lock_reserve(tr, TRACE_POWER,
+        event = trace_buffer_lock_reserve(buffer, TRACE_POWER,
                                           sizeof(*entry), 0, 0);
         if (!event)
                 goto out;
         entry   = ring_buffer_event_data(event);
         entry->state_data = *it;
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                trace_buffer_unlock_commit(tr, event, 0, 0);
+        if (!filter_check_discard(call, entry, buffer, event))
+                trace_buffer_unlock_commit(buffer, event, 0, 0);
  out:
         preempt_enable();
 }
@@ -144,14 +150,12 @@ static void power_trace_reset(struct trace_array *tr)
 
 static int power_trace_init(struct trace_array *tr)
 {
-        int cpu;
         power_trace = tr;
 
         trace_power_enabled = 1;
         tracing_power_register();
 
-        for_each_cpu(cpu, cpu_possible_mask)
-                tracing_reset(tr, cpu);
+        tracing_reset_online_cpus(tr);
         return 0;
 }
 
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index e1285d7b5488..5fca0f51fde4 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -28,10 +28,11 @@ tracing_sched_switch_trace(struct trace_array *tr,
                            unsigned long flags, int pc)
 {
         struct ftrace_event_call *call = &event_context_switch;
+        struct ring_buffer *buffer = tr->buffer;
         struct ring_buffer_event *event;
         struct ctx_switch_entry *entry;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_CTX,
+        event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
                                           sizeof(*entry), flags, pc);
         if (!event)
                 return;
@@ -44,8 +45,8 @@ tracing_sched_switch_trace(struct trace_array *tr,
         entry->next_state               = next->state;
         entry->next_cpu = task_cpu(next);
 
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                trace_buffer_unlock_commit(tr, event, flags, pc);
+        if (!filter_check_discard(call, entry, buffer, event))
+                trace_buffer_unlock_commit(buffer, event, flags, pc);
 }
 
 static void
@@ -86,8 +87,9 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
         struct ftrace_event_call *call = &event_wakeup;
         struct ring_buffer_event *event;
         struct ctx_switch_entry *entry;
+        struct ring_buffer *buffer = tr->buffer;
 
-        event = trace_buffer_lock_reserve(tr, TRACE_WAKE,
+        event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
                                           sizeof(*entry), flags, pc);
         if (!event)
                 return;
@@ -100,10 +102,10 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
         entry->next_state               = wakee->state;
         entry->next_cpu                 = task_cpu(wakee);
 
-        if (!filter_check_discard(call, entry, tr->buffer, event))
-                ring_buffer_unlock_commit(tr->buffer, event);
-        ftrace_trace_stack(tr, flags, 6, pc);
-        ftrace_trace_userstack(tr, flags, pc);
+        if (!filter_check_discard(call, entry, buffer, event))
+                ring_buffer_unlock_commit(buffer, event);
+        ftrace_trace_stack(tr->buffer, flags, 6, pc);
+        ftrace_trace_userstack(tr->buffer, flags, pc);
 }
 
 static void
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index eacb27225173..ad69f105a7c6 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -186,11 +186,6 @@ out:
 
 static void __wakeup_reset(struct trace_array *tr)
 {
-        int cpu;
-
-        for_each_possible_cpu(cpu)
-                tracing_reset(tr, cpu);
-
         wakeup_cpu = -1;
         wakeup_prio = -1;
 
@@ -204,6 +199,8 @@ static void wakeup_reset(struct trace_array *tr)
 {
         unsigned long flags;
 
+        tracing_reset_online_cpus(tr);
+
         local_irq_save(flags);
         __raw_spin_lock(&wakeup_lock);
         __wakeup_reset(tr);
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index e7c676e50a7f..dfc55fed2099 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -11,8 +11,8 @@
 static DEFINE_MUTEX(syscall_trace_lock);
 static int sys_refcount_enter;
 static int sys_refcount_exit;
-static DECLARE_BITMAP(enabled_enter_syscalls, FTRACE_SYSCALL_MAX);
-static DECLARE_BITMAP(enabled_exit_syscalls, FTRACE_SYSCALL_MAX);
+static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
+static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
 
 enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags)
@@ -223,10 +223,13 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id)
         struct syscall_trace_enter *entry;
         struct syscall_metadata *sys_data;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         int size;
         int syscall_nr;
 
         syscall_nr = syscall_get_nr(current, regs);
+        if (syscall_nr < 0)
+                return;
         if (!test_bit(syscall_nr, enabled_enter_syscalls))
                 return;
 
@@ -236,8 +239,8 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id)
 
         size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
 
-        event = trace_current_buffer_lock_reserve(sys_data->enter_id, size,
-                                                        0, 0);
+        event = trace_current_buffer_lock_reserve(&buffer, sys_data->enter_id,
+                                                  size, 0, 0);
         if (!event)
                 return;
 
@@ -245,8 +248,9 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id)
         entry->nr = syscall_nr;
         syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
 
-        if (!filter_current_check_discard(sys_data->enter_event, entry, event))
-                trace_current_buffer_unlock_commit(event, 0, 0);
+        if (!filter_current_check_discard(buffer, sys_data->enter_event,
+                                          entry, event))
+                trace_current_buffer_unlock_commit(buffer, event, 0, 0);
 }
 
 void ftrace_syscall_exit(struct pt_regs *regs, long ret)
@@ -254,9 +258,12 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret)
         struct syscall_trace_exit *entry;
         struct syscall_metadata *sys_data;
         struct ring_buffer_event *event;
+        struct ring_buffer *buffer;
         int syscall_nr;
 
         syscall_nr = syscall_get_nr(current, regs);
+        if (syscall_nr < 0)
+                return;
         if (!test_bit(syscall_nr, enabled_exit_syscalls))
                 return;
 
@@ -264,7 +271,7 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret)
         if (!sys_data)
                 return;
 
-        event = trace_current_buffer_lock_reserve(sys_data->exit_id,
+        event = trace_current_buffer_lock_reserve(&buffer, sys_data->exit_id,
                                 sizeof(*entry), 0, 0);
         if (!event)
                 return;
@@ -273,8 +280,9 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret)
         entry->nr = syscall_nr;
         entry->ret = syscall_get_return_value(current, regs);
 
-        if (!filter_current_check_discard(sys_data->exit_event, entry, event))
-                trace_current_buffer_unlock_commit(event, 0, 0);
+        if (!filter_current_check_discard(buffer, sys_data->exit_event,
+                                          entry, event))
+                trace_current_buffer_unlock_commit(buffer, event, 0, 0);
 }
 
 int reg_event_syscall_enter(struct ftrace_event_call *call)
@@ -285,7 +293,7 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
 
         name = (char *)call->data;
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return -ENOSYS;
         mutex_lock(&syscall_trace_lock);
         if (!sys_refcount_enter)
@@ -308,7 +316,7 @@ void unreg_event_syscall_enter(struct ftrace_event_call *call)
 
         name = (char *)call->data;
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return;
         mutex_lock(&syscall_trace_lock);
         sys_refcount_enter--;
@@ -326,7 +334,7 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
 
         name = call->data;
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return -ENOSYS;
         mutex_lock(&syscall_trace_lock);
         if (!sys_refcount_exit)
@@ -349,7 +357,7 @@ void unreg_event_syscall_exit(struct ftrace_event_call *call)
 
         name = call->data;
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return;
         mutex_lock(&syscall_trace_lock);
         sys_refcount_exit--;
@@ -369,8 +377,8 @@ struct trace_event event_syscall_exit = {
 
 #ifdef CONFIG_EVENT_PROFILE
 
-static DECLARE_BITMAP(enabled_prof_enter_syscalls, FTRACE_SYSCALL_MAX);
-static DECLARE_BITMAP(enabled_prof_exit_syscalls, FTRACE_SYSCALL_MAX);
+static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls);
+static DECLARE_BITMAP(enabled_prof_exit_syscalls, NR_syscalls);
 static int sys_prof_refcount_enter;
 static int sys_prof_refcount_exit;
 
@@ -416,7 +424,7 @@ int reg_prof_syscall_enter(char *name)
         int num;
 
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return -ENOSYS;
 
         mutex_lock(&syscall_trace_lock);
@@ -438,7 +446,7 @@ void unreg_prof_syscall_enter(char *name)
         int num;
 
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return;
 
         mutex_lock(&syscall_trace_lock);
@@ -477,7 +485,7 @@ int reg_prof_syscall_exit(char *name)
         int num;
 
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return -ENOSYS;
 
         mutex_lock(&syscall_trace_lock);
@@ -499,7 +507,7 @@ void unreg_prof_syscall_exit(char *name)
         int num;
 
         num = syscall_name_to_nr(name);
-        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+        if (num < 0 || num >= NR_syscalls)
                 return;
 
         mutex_lock(&syscall_trace_lock);