1 files changed, 30 insertions, 32 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4b1122d0df3..9ec59f54115 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -101,10 +101,7 @@ 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
@@ -744,13 +741,6 @@ __acquires(kernel_lock)
 		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;
@@ -832,7 +822,6 @@ __acquires(kernel_lock)
 #endif
 
  out_unlock:
-	lock_kernel();
 	return ret;
 }
 
@@ -1493,11 +1482,6 @@ 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 */
@@ -1595,7 +1579,7 @@ 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);
@@ -1630,19 +1614,19 @@ 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;
@@ -2003,7 +1987,7 @@ 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;
 
@@ -3193,7 +3177,7 @@ 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;
 
@@ -3276,7 +3260,7 @@ 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;
@@ -3332,7 +3316,7 @@ 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;
 	}
@@ -3479,6 +3463,7 @@ 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;
@@ -3500,11 +3485,15 @@ 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)
@@ -4402,7 +4391,7 @@ 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. */
@@ -4417,6 +4406,13 @@ 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)
 {
@@ -4442,8 +4438,10 @@ __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;
@@ -4492,7 +4490,7 @@ __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);
@@ -4514,7 +4512,7 @@ __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();
 	}