1 files changed, 120 insertions, 124 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8a76339a9e6..dc53ecb8058 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -17,7 +17,6 @@
 #include <linux/writeback.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
-#include <linux/smp_lock.h>
 #include <linux/notifier.h>
 #include <linux/irqflags.h>
 #include <linux/debugfs.h>
@@ -101,10 +100,7 @@ static inline void ftrace_enable_cpu(void)
 	preempt_enable();
 }
 
-static cpumask_var_t __read_mostly	tracing_buffer_mask;
-
-#define for_each_tracing_cpu(cpu)	\
-	for_each_cpu(cpu, tracing_buffer_mask)
+cpumask_var_t __read_mostly	tracing_buffer_mask;
 
 /*
  * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
@@ -344,7 +340,7 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
 /* trace_flags holds trace_options default values */
 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;
+	TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD;
 
 static int trace_stop_count;
 static DEFINE_SPINLOCK(tracing_start_lock);
@@ -428,6 +424,7 @@ static const char *trace_options[] = {
 	"latency-format",
 	"sleep-time",
 	"graph-time",
+	"record-cmd",
 	NULL
 };
 
@@ -659,6 +656,10 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 		return;
 
 	WARN_ON_ONCE(!irqs_disabled());
+	if (!current_trace->use_max_tr) {
+		WARN_ON_ONCE(1);
+		return;
+	}
 	arch_spin_lock(&ftrace_max_lock);
 
 	tr->buffer = max_tr.buffer;
@@ -685,6 +686,11 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 		return;
 
 	WARN_ON_ONCE(!irqs_disabled());
+	if (!current_trace->use_max_tr) {
+		WARN_ON_ONCE(1);
+		return;
+	}
+
 	arch_spin_lock(&ftrace_max_lock);
 
 	ftrace_disable_cpu();
@@ -729,18 +735,11 @@ __acquires(kernel_lock)
 		return -1;
 	}
 
-	if (strlen(type->name) > MAX_TRACER_SIZE) {
+	if (strlen(type->name) >= MAX_TRACER_SIZE) {
 		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
 		return -1;
 	}
 
-	/*
-	 * When this gets called we hold the BKL which means that
-	 * preemption is disabled. Various trace selftests however
-	 * need to disable and enable preemption for successful tests.
-	 * So we drop the BKL here and grab it after the tests again.
-	 */
-	unlock_kernel();
 	mutex_lock(&trace_types_lock);
 
 	tracing_selftest_running = true;
@@ -822,7 +821,6 @@ __acquires(kernel_lock)
 #endif
 
  out_unlock:
-	lock_kernel();
 	return ret;
 }
 
@@ -1285,6 +1283,8 @@ void trace_dump_stack(void)
 	__ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count());
 }
 
+static DEFINE_PER_CPU(int, user_stack_count);
+
 void
 ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 {
@@ -1303,10 +1303,20 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 	if (unlikely(in_nmi()))
 		return;
 
+	/*
+	 * prevent recursion, since the user stack tracing may
+	 * trigger other kernel events.
+	 */
+	preempt_disable();
+	if (__this_cpu_read(user_stack_count))
+		goto out;
+
+	__this_cpu_inc(user_stack_count);
+
 	event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
 					  sizeof(*entry), flags, pc);
 	if (!event)
-		return;
+		goto out_drop_count;
 	entry	= ring_buffer_event_data(event);
 
 	entry->tgid		= current->tgid;
@@ -1320,6 +1330,11 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 	save_stack_trace_user(&trace);
 	if (!filter_check_discard(call, entry, buffer, event))
 		ring_buffer_unlock_commit(buffer, event);
+
+ out_drop_count:
+	__this_cpu_dec(user_stack_count);
+ out:
+	preempt_enable();
 }
 
 #ifdef UNUSED
@@ -1331,61 +1346,6 @@ static void __trace_userstack(struct trace_array *tr, unsigned long flags)
 
 #endif /* CONFIG_STACKTRACE */
 
-static void
-ftrace_trace_special(void *__tr,
-		     unsigned long arg1, unsigned long arg2, unsigned long arg3,
-		     int pc)
-{
-	struct ftrace_event_call *call = &event_special;
-	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(buffer, TRACE_SPECIAL,
-					  sizeof(*entry), 0, pc);
-	if (!event)
-		return;
-	entry	= ring_buffer_event_data(event);
-	entry->arg1			= arg1;
-	entry->arg2			= arg2;
-	entry->arg3			= arg3;
-
-	if (!filter_check_discard(call, entry, buffer, event))
-		trace_buffer_unlock_commit(buffer, event, 0, pc);
-}
-
-void
-__trace_special(void *__tr, void *__data,
-		unsigned long arg1, unsigned long arg2, unsigned long arg3)
-{
-	ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
-}
-
-void
-ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
-{
-	struct trace_array *tr = &global_trace;
-	struct trace_array_cpu *data;
-	unsigned long flags;
-	int cpu;
-	int pc;
-
-	if (tracing_disabled)
-		return;
-
-	pc = preempt_count();
-	local_irq_save(flags);
-	cpu = raw_smp_processor_id();
-	data = tr->data[cpu];
-
-	if (likely(atomic_inc_return(&data->disabled) == 1))
-		ftrace_trace_special(tr, arg1, arg2, arg3, pc);
-
-	atomic_dec(&data->disabled);
-	local_irq_restore(flags);
-}
-
 /**
  * trace_vbprintk - write binary msg to tracing buffer
  *
@@ -1404,7 +1364,6 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 	struct bprint_entry *entry;
 	unsigned long flags;
 	int disable;
-	int resched;
 	int cpu, len = 0, size, pc;
 
 	if (unlikely(tracing_selftest_running || tracing_disabled))
@@ -1414,7 +1373,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 	pause_graph_tracing();
 
 	pc = preempt_count();
-	resched = ftrace_preempt_disable();
+	preempt_disable_notrace();
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
 
@@ -1452,7 +1411,7 @@ out_unlock:
 
 out:
 	atomic_dec_return(&data->disabled);
-	ftrace_preempt_enable(resched);
+	preempt_enable_notrace();
 	unpause_graph_tracing();
 
 	return len;
@@ -1539,11 +1498,6 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 }
 EXPORT_SYMBOL_GPL(trace_vprintk);
 
-enum trace_file_type {
-	TRACE_FILE_LAT_FMT	= 1,
-	TRACE_FILE_ANNOTATE	= 2,
-};
-
 static void trace_iterator_increment(struct trace_iterator *iter)
 {
 	/* Don't allow ftrace to trace into the ring buffers */
@@ -1641,7 +1595,7 @@ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 }
 
 /* Find the next real entry, and increment the iterator to the next entry */
-static void *find_next_entry_inc(struct trace_iterator *iter)
+void *trace_find_next_entry_inc(struct trace_iterator *iter)
 {
 	iter->ent = __find_next_entry(iter, &iter->cpu,
 				      &iter->lost_events, &iter->ts);
@@ -1676,19 +1630,19 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos)
 		return NULL;
 
 	if (iter->idx < 0)
-		ent = find_next_entry_inc(iter);
+		ent = trace_find_next_entry_inc(iter);
 	else
 		ent = iter;
 
 	while (ent && iter->idx < i)
-		ent = find_next_entry_inc(iter);
+		ent = trace_find_next_entry_inc(iter);
 
 	iter->pos = *pos;
 
 	return ent;
 }
 
-static void tracing_iter_reset(struct trace_iterator *iter, int cpu)
+void tracing_iter_reset(struct trace_iterator *iter, int cpu)
 {
 	struct trace_array *tr = iter->tr;
 	struct ring_buffer_event *event;
@@ -1936,7 +1890,7 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
 	}
 
 	if (event)
-		return event->trace(iter, sym_flags);
+		return event->funcs->trace(iter, sym_flags, event);
 
 	if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
 		goto partial;
@@ -1962,7 +1916,7 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
 
 	event = ftrace_find_event(entry->type);
 	if (event)
-		return event->raw(iter, 0);
+		return event->funcs->raw(iter, 0, event);
 
 	if (!trace_seq_printf(s, "%d ?\n", entry->type))
 		goto partial;
@@ -1989,7 +1943,7 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
 
 	event = ftrace_find_event(entry->type);
 	if (event) {
-		enum print_line_t ret = event->hex(iter, 0);
+		enum print_line_t ret = event->funcs->hex(iter, 0, event);
 		if (ret != TRACE_TYPE_HANDLED)
 			return ret;
 	}
@@ -2014,7 +1968,8 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 	}
 
 	event = ftrace_find_event(entry->type);
-	return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
+	return event ? event->funcs->binary(iter, 0, event) :
+		TRACE_TYPE_HANDLED;
 }
 
 int trace_empty(struct trace_iterator *iter)
@@ -2048,7 +2003,7 @@ int trace_empty(struct trace_iterator *iter)
 }
 
 /*  Called with trace_event_read_lock() held. */
-static enum print_line_t print_trace_line(struct trace_iterator *iter)
+enum print_line_t print_trace_line(struct trace_iterator *iter)
 {
 	enum print_line_t ret;
 
@@ -2257,7 +2212,7 @@ int tracing_open_generic(struct inode *inode, struct file *filp)
 
 static int tracing_release(struct inode *inode, struct file *file)
 {
-	struct seq_file *m = (struct seq_file *)file->private_data;
+	struct seq_file *m = file->private_data;
 	struct trace_iterator *iter;
 	int cpu;
 
@@ -2381,11 +2336,19 @@ tracing_write_stub(struct file *filp, const char __user *ubuf,
 	return count;
 }
 
+static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
+{
+	if (file->f_mode & FMODE_READ)
+		return seq_lseek(file, offset, origin);
+	else
+		return 0;
+}
+
 static const struct file_operations tracing_fops = {
 	.open		= tracing_open,
 	.read		= seq_read,
 	.write		= tracing_write_stub,
-	.llseek		= seq_lseek,
+	.llseek		= tracing_seek,
 	.release	= tracing_release,
 };
 
@@ -2393,6 +2356,7 @@ static const struct file_operations show_traces_fops = {
 	.open		= show_traces_open,
 	.read		= seq_read,
 	.release	= seq_release,
+	.llseek		= seq_lseek,
 };
 
 /*
@@ -2486,6 +2450,7 @@ static const struct file_operations tracing_cpumask_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_cpumask_read,
 	.write		= tracing_cpumask_write,
+	.llseek		= generic_file_llseek,
 };
 
 static int tracing_trace_options_show(struct seq_file *m, void *v)
@@ -2561,6 +2526,9 @@ static void set_tracer_flags(unsigned int mask, int enabled)
 		trace_flags |= mask;
 	else
 		trace_flags &= ~mask;
+
+	if (mask == TRACE_ITER_RECORD_CMD)
+		trace_event_enable_cmd_record(enabled);
 }
 
 static ssize_t
@@ -2652,6 +2620,7 @@ tracing_readme_read(struct file *filp, char __user *ubuf,
 static const struct file_operations tracing_readme_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_readme_read,
+	.llseek		= generic_file_llseek,
 };
 
 static ssize_t
@@ -2702,6 +2671,7 @@ tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
 static const struct file_operations tracing_saved_cmdlines_fops = {
     .open       = tracing_open_generic,
     .read       = tracing_saved_cmdlines_read,
+    .llseek	= generic_file_llseek,
 };
 
 static ssize_t
@@ -2797,6 +2767,9 @@ static int tracing_resize_ring_buffer(unsigned long size)
 	if (ret < 0)
 		return ret;
 
+	if (!current_trace->use_max_tr)
+		goto out;
+
 	ret = ring_buffer_resize(max_tr.buffer, size);
 	if (ret < 0) {
 		int r;
@@ -2824,11 +2797,14 @@ static int tracing_resize_ring_buffer(unsigned long size)
 		return ret;
 	}
 
+	max_tr.entries = size;
+ out:
 	global_trace.entries = size;
 
 	return ret;
 }
 
+
 /**
  * tracing_update_buffers - used by tracing facility to expand ring buffers
  *
@@ -2889,12 +2865,26 @@ static int tracing_set_tracer(const char *buf)
 	trace_branch_disable();
 	if (current_trace && current_trace->reset)
 		current_trace->reset(tr);
-
+	if (current_trace && current_trace->use_max_tr) {
+		/*
+		 * We don't free the ring buffer. instead, resize it because
+		 * The max_tr ring buffer has some state (e.g. ring->clock) and
+		 * we want preserve it.
+		 */
+		ring_buffer_resize(max_tr.buffer, 1);
+		max_tr.entries = 1;
+	}
 	destroy_trace_option_files(topts);
 
 	current_trace = t;
 
 	topts = create_trace_option_files(current_trace);
+	if (current_trace->use_max_tr) {
+		ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
+		if (ret < 0)
+			goto out;
+		max_tr.entries = global_trace.entries;
+	}
 
 	if (t->init) {
 		ret = tracer_init(t, tr);
@@ -3031,6 +3021,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
 	if (iter->trace->pipe_open)
 		iter->trace->pipe_open(iter);
 
+	nonseekable_open(inode, filp);
 out:
 	mutex_unlock(&trace_types_lock);
 	return ret;
@@ -3210,7 +3201,7 @@ waitagain:
 
 	trace_event_read_lock();
 	trace_access_lock(iter->cpu_file);
-	while (find_next_entry_inc(iter) != NULL) {
+	while (trace_find_next_entry_inc(iter) != NULL) {
 		enum print_line_t ret;
 		int len = iter->seq.len;
 
@@ -3293,7 +3284,7 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
 		if (ret != TRACE_TYPE_NO_CONSUME)
 			trace_consume(iter);
 		rem -= count;
-		if (!find_next_entry_inc(iter))	{
+		if (!trace_find_next_entry_inc(iter))	{
 			rem = 0;
 			iter->ent = NULL;
 			break;
@@ -3349,7 +3340,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
 	if (ret <= 0)
 		goto out_err;
 
-	if (!iter->ent && !find_next_entry_inc(iter)) {
+	if (!iter->ent && !trace_find_next_entry_inc(iter)) {
 		ret = -EFAULT;
 		goto out_err;
 	}
@@ -3476,7 +3467,6 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 	}
 
 	tracing_start();
-	max_tr.entries = global_trace.entries;
 	mutex_unlock(&trace_types_lock);
 
 	return cnt;
@@ -3497,6 +3487,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 					size_t cnt, loff_t *fpos)
 {
 	char *buf;
+	size_t written;
 
 	if (tracing_disabled)
 		return -EINVAL;
@@ -3518,11 +3509,15 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 	} else
 		buf[cnt] = '\0';
 
-	cnt = mark_printk("%s", buf);
+	written = mark_printk("%s", buf);
 	kfree(buf);
-	*fpos += cnt;
+	*fpos += written;
 
-	return cnt;
+	/* don't tell userspace we wrote more - it might confuse them */
+	if (written > cnt)
+		written = cnt;
+
+	return written;
 }
 
 static int tracing_clock_show(struct seq_file *m, void *v)
@@ -3589,18 +3584,21 @@ static const struct file_operations tracing_max_lat_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_max_lat_read,
 	.write		= tracing_max_lat_write,
+	.llseek		= generic_file_llseek,
 };
 
 static const struct file_operations tracing_ctrl_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_ctrl_read,
 	.write		= tracing_ctrl_write,
+	.llseek		= generic_file_llseek,
 };
 
 static const struct file_operations set_tracer_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_set_trace_read,
 	.write		= tracing_set_trace_write,
+	.llseek		= generic_file_llseek,
 };
 
 static const struct file_operations tracing_pipe_fops = {
@@ -3609,17 +3607,20 @@ static const struct file_operations tracing_pipe_fops = {
 	.read		= tracing_read_pipe,
 	.splice_read	= tracing_splice_read_pipe,
 	.release	= tracing_release_pipe,
+	.llseek		= no_llseek,
 };
 
 static const struct file_operations tracing_entries_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_entries_read,
 	.write		= tracing_entries_write,
+	.llseek		= generic_file_llseek,
 };
 
 static const struct file_operations tracing_mark_fops = {
 	.open		= tracing_open_generic,
 	.write		= tracing_mark_write,
+	.llseek		= generic_file_llseek,
 };
 
 static const struct file_operations trace_clock_fops = {
@@ -3665,7 +3666,6 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 		     size_t count, loff_t *ppos)
 {
 	struct ftrace_buffer_info *info = filp->private_data;
-	unsigned int pos;
 	ssize_t ret;
 	size_t size;
 
@@ -3692,11 +3692,6 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 	if (ret < 0)
 		return 0;
 
-	pos = ring_buffer_page_len(info->spare);
-
-	if (pos < PAGE_SIZE)
-		memset(info->spare + pos, 0, PAGE_SIZE - pos);
-
 read:
 	size = PAGE_SIZE - info->read;
 	if (size > count)
@@ -3931,6 +3926,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
 static const struct file_operations tracing_stats_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_stats_read,
+	.llseek		= generic_file_llseek,
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -3967,6 +3963,7 @@ tracing_read_dyn_info(struct file *filp, char __user *ubuf,
 static const struct file_operations tracing_dyn_info_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_read_dyn_info,
+	.llseek		= generic_file_llseek,
 };
 #endif
 
@@ -4023,13 +4020,9 @@ static void tracing_init_debugfs_percpu(long cpu)
 {
 	struct dentry *d_percpu = tracing_dentry_percpu();
 	struct dentry *d_cpu;
-	/* strlen(cpu) + MAX(log10(cpu)) + '\0' */
-	char cpu_dir[7];
+	char cpu_dir[30]; /* 30 characters should be more than enough */
 
-	if (cpu > 999 || cpu < 0)
-		return;
-
-	sprintf(cpu_dir, "cpu%ld", cpu);
+	snprintf(cpu_dir, 30, "cpu%ld", cpu);
 	d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
 	if (!d_cpu) {
 		pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
@@ -4120,6 +4113,7 @@ static const struct file_operations trace_options_fops = {
 	.open = tracing_open_generic,
 	.read = trace_options_read,
 	.write = trace_options_write,
+	.llseek	= generic_file_llseek,
 };
 
 static ssize_t
@@ -4171,6 +4165,7 @@ static const struct file_operations trace_options_core_fops = {
 	.open = tracing_open_generic,
 	.read = trace_options_core_read,
 	.write = trace_options_core_write,
+	.llseek = generic_file_llseek,
 };
 
 struct dentry *trace_create_file(const char *name,
@@ -4360,9 +4355,6 @@ static __init int tracer_init_debugfs(void)
 	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
 			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
 #endif
-#ifdef CONFIG_SYSPROF_TRACER
-	init_tracer_sysprof_debugfs(d_tracer);
-#endif
 
 	create_trace_options_dir();
 
@@ -4419,7 +4411,7 @@ static struct notifier_block trace_die_notifier = {
  */
 #define KERN_TRACE		KERN_EMERG
 
-static void
+void
 trace_printk_seq(struct trace_seq *s)
 {
 	/* Probably should print a warning here. */
@@ -4434,6 +4426,13 @@ trace_printk_seq(struct trace_seq *s)
 	trace_seq_init(s);
 }
 
+void trace_init_global_iter(struct trace_iterator *iter)
+{
+	iter->tr = &global_trace;
+	iter->trace = current_trace;
+	iter->cpu_file = TRACE_PIPE_ALL_CPU;
+}
+
 static void
 __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
 {
@@ -4459,8 +4458,10 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
 	if (disable_tracing)
 		ftrace_kill();
 
+	trace_init_global_iter(&iter);
+
 	for_each_tracing_cpu(cpu) {
-		atomic_inc(&global_trace.data[cpu]->disabled);
+		atomic_inc(&iter.tr->data[cpu]->disabled);
 	}
 
 	old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
@@ -4509,7 +4510,7 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
 		iter.iter_flags |= TRACE_FILE_LAT_FMT;
 		iter.pos = -1;
 
-		if (find_next_entry_inc(&iter) != NULL) {
+		if (trace_find_next_entry_inc(&iter) != NULL) {
 			int ret;
 
 			ret = print_trace_line(&iter);
@@ -4531,7 +4532,7 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
 		trace_flags |= old_userobj;
 
 		for_each_tracing_cpu(cpu) {
-			atomic_dec(&global_trace.data[cpu]->disabled);
+			atomic_dec(&iter.tr->data[cpu]->disabled);
 		}
 		tracing_on();
 	}
@@ -4580,16 +4581,14 @@ __init static int tracer_alloc_buffers(void)
 
 
 #ifdef CONFIG_TRACER_MAX_TRACE
-	max_tr.buffer = ring_buffer_alloc(ring_buf_size,
-					     TRACE_BUFFER_FLAGS);
+	max_tr.buffer = ring_buffer_alloc(1, TRACE_BUFFER_FLAGS);
 	if (!max_tr.buffer) {
 		printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
 		WARN_ON(1);
 		ring_buffer_free(global_trace.buffer);
 		goto out_free_cpumask;
 	}
-	max_tr.entries = ring_buffer_size(max_tr.buffer);
-	WARN_ON(max_tr.entries != global_trace.entries);
+	max_tr.entries = 1;
 #endif
 
 	/* Allocate the first page for all buffers */
@@ -4602,9 +4601,6 @@ __init static int tracer_alloc_buffers(void)
 
 	register_tracer(&nop_trace);
 	current_trace = &nop_trace;
-#ifdef CONFIG_BOOT_TRACER
-	register_tracer(&boot_tracer);
-#endif
 	/* All seems OK, enable tracing */
 	tracing_disabled = 0;