diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 6c38e4f..716d8c5 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -23,6 +23,8 @@
 #include <linux/list.h>
 #include <linux/hash.h>
 
+static struct perf_session *session;
+
 /* based on kernel/lockdep.c */
 #define LOCKHASH_BITS		12
 #define LOCKHASH_SIZE		(1UL << LOCKHASH_BITS)
@@ -32,9 +34,6 @@
 #define __lockhashfn(key)	hash_long((unsigned long)key, LOCKHASH_BITS)
 #define lockhashentry(key)	(lockhash_table + __lockhashfn((key)))
 
-#define LOCK_STATE_UNLOCKED	0	       /* initial state */
-#define LOCK_STATE_LOCKED	1
-
 struct lock_stat {
 	struct list_head	hash_entry;
 	struct rb_node		rb;		/* used for sorting */
@@ -47,20 +46,151 @@
 	void			*addr;		/* address of lockdep_map, used as ID */
 	char			*name;		/* for strcpy(), we cannot use const */
 
-	int			state;
-	u64			prev_event_time; /* timestamp of previous event */
-
-	unsigned int		nr_acquired;
 	unsigned int		nr_acquire;
+	unsigned int		nr_acquired;
 	unsigned int		nr_contended;
 	unsigned int		nr_release;
 
+	unsigned int		nr_readlock;
+	unsigned int		nr_trylock;
 	/* these times are in nano sec. */
 	u64			wait_time_total;
 	u64			wait_time_min;
 	u64			wait_time_max;
+
+	int			discard; /* flag of blacklist */
 };
 
+/*
+ * States of lock_seq_stat
+ *
+ * UNINITIALIZED is required for detecting first event of acquire.
+ * As the nature of lock events, there is no guarantee
+ * that the first event for the locks are acquire,
+ * it can be acquired, contended or release.
+ */
+#define SEQ_STATE_UNINITIALIZED      0	       /* initial state */
+#define SEQ_STATE_RELEASED	1
+#define SEQ_STATE_ACQUIRING	2
+#define SEQ_STATE_ACQUIRED	3
+#define SEQ_STATE_READ_ACQUIRED	4
+#define SEQ_STATE_CONTENDED	5
+
+/*
+ * MAX_LOCK_DEPTH
+ * Imported from include/linux/sched.h.
+ * Should this be synchronized?
+ */
+#define MAX_LOCK_DEPTH 48
+
+/*
+ * struct lock_seq_stat:
+ * Place to put on state of one lock sequence
+ * 1) acquire -> acquired -> release
+ * 2) acquire -> contended -> acquired -> release
+ * 3) acquire (with read or try) -> release
+ * 4) Are there other patterns?
+ */
+struct lock_seq_stat {
+	struct list_head        list;
+	int			state;
+	u64			prev_event_time;
+	void                    *addr;
+
+	int                     read_count;
+};
+
+struct thread_stat {
+	struct rb_node		rb;
+
+	u32                     tid;
+	struct list_head        seq_list;
+};
+
+static struct rb_root		thread_stats;
+
+static struct thread_stat *thread_stat_find(u32 tid)
+{
+	struct rb_node *node;
+	struct thread_stat *st;
+
+	node = thread_stats.rb_node;
+	while (node) {
+		st = container_of(node, struct thread_stat, rb);
+		if (st->tid == tid)
+			return st;
+		else if (tid < st->tid)
+			node = node->rb_left;
+		else
+			node = node->rb_right;
+	}
+
+	return NULL;
+}
+
+static void thread_stat_insert(struct thread_stat *new)
+{
+	struct rb_node **rb = &thread_stats.rb_node;
+	struct rb_node *parent = NULL;
+	struct thread_stat *p;
+
+	while (*rb) {
+		p = container_of(*rb, struct thread_stat, rb);
+		parent = *rb;
+
+		if (new->tid < p->tid)
+			rb = &(*rb)->rb_left;
+		else if (new->tid > p->tid)
+			rb = &(*rb)->rb_right;
+		else
+			BUG_ON("inserting invalid thread_stat\n");
+	}
+
+	rb_link_node(&new->rb, parent, rb);
+	rb_insert_color(&new->rb, &thread_stats);
+}
+
+static struct thread_stat *thread_stat_findnew_after_first(u32 tid)
+{
+	struct thread_stat *st;
+
+	st = thread_stat_find(tid);
+	if (st)
+		return st;
+
+	st = zalloc(sizeof(struct thread_stat));
+	if (!st)
+		die("memory allocation failed\n");
+
+	st->tid = tid;
+	INIT_LIST_HEAD(&st->seq_list);
+
+	thread_stat_insert(st);
+
+	return st;
+}
+
+static struct thread_stat *thread_stat_findnew_first(u32 tid);
+static struct thread_stat *(*thread_stat_findnew)(u32 tid) =
+	thread_stat_findnew_first;
+
+static struct thread_stat *thread_stat_findnew_first(u32 tid)
+{
+	struct thread_stat *st;
+
+	st = zalloc(sizeof(struct thread_stat));
+	if (!st)
+		die("memory allocation failed\n");
+	st->tid = tid;
+	INIT_LIST_HEAD(&st->seq_list);
+
+	rb_link_node(&st->rb, NULL, &thread_stats.rb_node);
+	rb_insert_color(&st->rb, &thread_stats);
+
+	thread_stat_findnew = thread_stat_findnew_after_first;
+	return st;
+}
+
 /* build simple key function one is bigger than two */
 #define SINGLE_KEY(member)						\
 	static int lock_stat_key_ ## member(struct lock_stat *one,	\
@@ -175,8 +305,6 @@
 		goto alloc_failed;
 	strcpy(new->name, name);
 
-	/* LOCK_STATE_UNLOCKED == 0 isn't guaranteed forever */
-	new->state = LOCK_STATE_UNLOCKED;
 	new->wait_time_min = ULLONG_MAX;
 
 	list_add(&new->hash_entry, entry);
@@ -198,6 +326,7 @@
 struct trace_acquire_event {
 	void			*addr;
 	const char		*name;
+	int			flag;
 };
 
 struct trace_acquired_event {
@@ -241,120 +370,246 @@
 			      struct thread *thread);
 };
 
+static struct lock_seq_stat *get_seq(struct thread_stat *ts, void *addr)
+{
+	struct lock_seq_stat *seq;
+
+	list_for_each_entry(seq, &ts->seq_list, list) {
+		if (seq->addr == addr)
+			return seq;
+	}
+
+	seq = zalloc(sizeof(struct lock_seq_stat));
+	if (!seq)
+		die("Not enough memory\n");
+	seq->state = SEQ_STATE_UNINITIALIZED;
+	seq->addr = addr;
+
+	list_add(&seq->list, &ts->seq_list);
+	return seq;
+}
+
+static int bad_hist[4];
+
 static void
 report_lock_acquire_event(struct trace_acquire_event *acquire_event,
 			struct event *__event __used,
 			int cpu __used,
-			u64 timestamp,
+			u64 timestamp __used,
 			struct thread *thread __used)
 {
-	struct lock_stat *st;
+	struct lock_stat *ls;
+	struct thread_stat *ts;
+	struct lock_seq_stat *seq;
 
-	st = lock_stat_findnew(acquire_event->addr, acquire_event->name);
+	ls = lock_stat_findnew(acquire_event->addr, acquire_event->name);
+	if (ls->discard)
+		return;
 
-	switch (st->state) {
-	case LOCK_STATE_UNLOCKED:
+	ts = thread_stat_findnew(thread->pid);
+	seq = get_seq(ts, acquire_event->addr);
+
+	switch (seq->state) {
+	case SEQ_STATE_UNINITIALIZED:
+	case SEQ_STATE_RELEASED:
+		if (!acquire_event->flag) {
+			seq->state = SEQ_STATE_ACQUIRING;
+		} else {
+			if (acquire_event->flag & 1)
+				ls->nr_trylock++;
+			if (acquire_event->flag & 2)
+				ls->nr_readlock++;
+			seq->state = SEQ_STATE_READ_ACQUIRED;
+			seq->read_count = 1;
+			ls->nr_acquired++;
+		}
 		break;
-	case LOCK_STATE_LOCKED:
+	case SEQ_STATE_READ_ACQUIRED:
+		if (acquire_event->flag & 2) {
+			seq->read_count++;
+			ls->nr_acquired++;
+			goto end;
+		} else {
+			goto broken;
+		}
+		break;
+	case SEQ_STATE_ACQUIRED:
+	case SEQ_STATE_ACQUIRING:
+	case SEQ_STATE_CONTENDED:
+broken:
+		/* broken lock sequence, discard it */
+		ls->discard = 1;
+		bad_hist[0]++;
+		list_del(&seq->list);
+		free(seq);
+		goto end;
 		break;
 	default:
-		BUG_ON(1);
+		BUG_ON("Unknown state of lock sequence found!\n");
 		break;
 	}
 
-	st->prev_event_time = timestamp;
+	ls->nr_acquire++;
+	seq->prev_event_time = timestamp;
+end:
+	return;
 }
 
 static void
 report_lock_acquired_event(struct trace_acquired_event *acquired_event,
 			 struct event *__event __used,
 			 int cpu __used,
-			 u64 timestamp,
+			 u64 timestamp __used,
 			 struct thread *thread __used)
 {
-	struct lock_stat *st;
+	struct lock_stat *ls;
+	struct thread_stat *ts;
+	struct lock_seq_stat *seq;
+	u64 contended_term;
 
-	st = lock_stat_findnew(acquired_event->addr, acquired_event->name);
+	ls = lock_stat_findnew(acquired_event->addr, acquired_event->name);
+	if (ls->discard)
+		return;
 
-	switch (st->state) {
-	case LOCK_STATE_UNLOCKED:
-		st->state = LOCK_STATE_LOCKED;
-		st->nr_acquired++;
+	ts = thread_stat_findnew(thread->pid);
+	seq = get_seq(ts, acquired_event->addr);
+
+	switch (seq->state) {
+	case SEQ_STATE_UNINITIALIZED:
+		/* orphan event, do nothing */
+		return;
+	case SEQ_STATE_ACQUIRING:
 		break;
-	case LOCK_STATE_LOCKED:
+	case SEQ_STATE_CONTENDED:
+		contended_term = timestamp - seq->prev_event_time;
+		ls->wait_time_total += contended_term;
+
+		if (contended_term < ls->wait_time_min)
+			ls->wait_time_min = contended_term;
+		else if (ls->wait_time_max < contended_term)
+			ls->wait_time_max = contended_term;
 		break;
+	case SEQ_STATE_RELEASED:
+	case SEQ_STATE_ACQUIRED:
+	case SEQ_STATE_READ_ACQUIRED:
+		/* broken lock sequence, discard it */
+		ls->discard = 1;
+		bad_hist[1]++;
+		list_del(&seq->list);
+		free(seq);
+		goto end;
+		break;
+
 	default:
-		BUG_ON(1);
+		BUG_ON("Unknown state of lock sequence found!\n");
 		break;
 	}
 
-	st->prev_event_time = timestamp;
+	seq->state = SEQ_STATE_ACQUIRED;
+	ls->nr_acquired++;
+	seq->prev_event_time = timestamp;
+end:
+	return;
 }
 
 static void
 report_lock_contended_event(struct trace_contended_event *contended_event,
 			  struct event *__event __used,
 			  int cpu __used,
-			  u64 timestamp,
+			  u64 timestamp __used,
 			  struct thread *thread __used)
 {
-	struct lock_stat *st;
+	struct lock_stat *ls;
+	struct thread_stat *ts;
+	struct lock_seq_stat *seq;
 
-	st = lock_stat_findnew(contended_event->addr, contended_event->name);
+	ls = lock_stat_findnew(contended_event->addr, contended_event->name);
+	if (ls->discard)
+		return;
 
-	switch (st->state) {
-	case LOCK_STATE_UNLOCKED:
+	ts = thread_stat_findnew(thread->pid);
+	seq = get_seq(ts, contended_event->addr);
+
+	switch (seq->state) {
+	case SEQ_STATE_UNINITIALIZED:
+		/* orphan event, do nothing */
+		return;
+	case SEQ_STATE_ACQUIRING:
 		break;
-	case LOCK_STATE_LOCKED:
-		st->nr_contended++;
+	case SEQ_STATE_RELEASED:
+	case SEQ_STATE_ACQUIRED:
+	case SEQ_STATE_READ_ACQUIRED:
+	case SEQ_STATE_CONTENDED:
+		/* broken lock sequence, discard it */
+		ls->discard = 1;
+		bad_hist[2]++;
+		list_del(&seq->list);
+		free(seq);
+		goto end;
 		break;
 	default:
-		BUG_ON(1);
+		BUG_ON("Unknown state of lock sequence found!\n");
 		break;
 	}
 
-	st->prev_event_time = timestamp;
+	seq->state = SEQ_STATE_CONTENDED;
+	ls->nr_contended++;
+	seq->prev_event_time = timestamp;
+end:
+	return;
 }
 
 static void
 report_lock_release_event(struct trace_release_event *release_event,
 			struct event *__event __used,
 			int cpu __used,
-			u64 timestamp,
+			u64 timestamp __used,
 			struct thread *thread __used)
 {
-	struct lock_stat *st;
-	u64 hold_time;
+	struct lock_stat *ls;
+	struct thread_stat *ts;
+	struct lock_seq_stat *seq;
 
-	st = lock_stat_findnew(release_event->addr, release_event->name);
+	ls = lock_stat_findnew(release_event->addr, release_event->name);
+	if (ls->discard)
+		return;
 
-	switch (st->state) {
-	case LOCK_STATE_UNLOCKED:
+	ts = thread_stat_findnew(thread->pid);
+	seq = get_seq(ts, release_event->addr);
+
+	switch (seq->state) {
+	case SEQ_STATE_UNINITIALIZED:
+		goto end;
 		break;
-	case LOCK_STATE_LOCKED:
-		st->state = LOCK_STATE_UNLOCKED;
-		hold_time = timestamp - st->prev_event_time;
-
-		if (timestamp < st->prev_event_time) {
-			/* terribly, this can happen... */
+	case SEQ_STATE_ACQUIRED:
+		break;
+	case SEQ_STATE_READ_ACQUIRED:
+		seq->read_count--;
+		BUG_ON(seq->read_count < 0);
+		if (!seq->read_count) {
+			ls->nr_release++;
 			goto end;
 		}
-
-		if (st->wait_time_min > hold_time)
-			st->wait_time_min = hold_time;
-		if (st->wait_time_max < hold_time)
-			st->wait_time_max = hold_time;
-		st->wait_time_total += hold_time;
-
-		st->nr_release++;
+		break;
+	case SEQ_STATE_ACQUIRING:
+	case SEQ_STATE_CONTENDED:
+	case SEQ_STATE_RELEASED:
+		/* broken lock sequence, discard it */
+		ls->discard = 1;
+		bad_hist[3]++;
+		goto free_seq;
 		break;
 	default:
-		BUG_ON(1);
+		BUG_ON("Unknown state of lock sequence found!\n");
 		break;
 	}
 
+	ls->nr_release++;
+free_seq:
+	list_del(&seq->list);
+	free(seq);
 end:
-	st->prev_event_time = timestamp;
+	return;
 }
 
 /* lock oriented handlers */
@@ -381,6 +636,7 @@
 	tmp = raw_field_value(event, "lockdep_addr", data);
 	memcpy(&acquire_event.addr, &tmp, sizeof(void *));
 	acquire_event.name = (char *)raw_field_ptr(event, "name", data);
+	acquire_event.flag = (int)raw_field_value(event, "flag", data);
 
 	if (trace_handler->acquire_event)
 		trace_handler->acquire_event(&acquire_event, event, cpu, timestamp, thread);
@@ -441,8 +697,8 @@
 }
 
 static void
-process_raw_event(void *data, int cpu,
-		  u64 timestamp, struct thread *thread)
+process_raw_event(void *data, int cpu __used,
+		  u64 timestamp __used, struct thread *thread __used)
 {
 	struct event *event;
 	int type;
@@ -604,14 +860,15 @@
 	}
 }
 
-static int process_sample_event(event_t *event, struct perf_session *session)
+static int process_sample_event(event_t *event, struct perf_session *s)
 {
 	struct thread *thread;
 	struct sample_data data;
 
 	bzero(&data, sizeof(struct sample_data));
-	event__parse_sample(event, session->sample_type, &data);
-	thread = perf_session__findnew(session, data.pid);
+	event__parse_sample(event, s->sample_type, &data);
+	/* CAUTION: using tid as thread.pid */
+	thread = perf_session__findnew(s, data.tid);
 
 	if (thread == NULL) {
 		pr_debug("problem processing %d event, skipping it.\n",
@@ -634,8 +891,8 @@
 {
 	struct lock_stat *st;
 	char cut_name[20];
+	int bad, total;
 
-	printf("%18s ", "ID");
 	printf("%20s ", "Name");
 	printf("%10s ", "acquired");
 	printf("%10s ", "contended");
@@ -646,11 +903,15 @@
 
 	printf("\n\n");
 
+	bad = total = 0;
 	while ((st = pop_from_result())) {
+		total++;
+		if (st->discard) {
+			bad++;
+			continue;
+		}
 		bzero(cut_name, 20);
 
-		printf("%p ", st->addr);
-
 		if (strlen(st->name) < 16) {
 			/* output raw name */
 			printf("%20s ", st->name);
@@ -673,6 +934,21 @@
 		       0 : st->wait_time_min);
 		printf("\n");
 	}
+
+	{
+		/* Output for debug, this have to be removed */
+		int i;
+		const char *name[4] =
+			{ "acquire", "acquired", "contended", "release" };
+
+		printf("\n=== output for debug===\n\n");
+		printf("bad:%d, total:%d\n", bad, total);
+		printf("bad rate:%f\n", (double)(bad / total));
+
+		printf("histogram of events caused bad sequence\n");
+		for (i = 0; i < 4; i++)
+			printf(" %10s: %d\n", name[i], bad_hist[i]);
+	}
 }
 
 static void dump_map(void)
@@ -692,8 +968,6 @@
 	.comm			= event__process_comm,
 };
 
-static struct perf_session *session;
-
 static int read_events(void)
 {
 	session = perf_session__new(input_name, O_RDONLY, 0);