4 files changed, 38 insertions, 15 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index beb21a51e1e..54cb9a7d15e 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -179,8 +179,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 
         if (ftrace_enabled) {
                 /* If we only have one func left, then call that directly */
-                if (ftrace_list == &ftrace_list_end ||
-                    ftrace_list->next == &ftrace_list_end)
+                if (ftrace_list->next == &ftrace_list_end)
                         ftrace_trace_function = ftrace_list->func;
         }
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2d6c2cf0c3b..caa4fda50f8 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -533,6 +533,12 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
         LIST_HEAD(pages);
         int i, cpu;
 
+        /*
+         * Always succeed at resizing a non-existent buffer:
+         */
+        if (!buffer)
+                return size;
+
         size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
         size *= BUF_PAGE_SIZE;
         buffer_size = buffer->pages * BUF_PAGE_SIZE;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4bf070bb527..4a904623e05 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -204,8 +204,9 @@ static DEFINE_MUTEX(trace_types_lock);
 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
 
-/* trace_flags holds iter_ctrl options */
-unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK;
+/* trace_flags holds trace_options default values */
+unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
+        TRACE_ITER_ANNOTATE;
 
 /**
  * trace_wake_up - wake up tasks waiting for trace input
@@ -261,6 +262,7 @@ static const char *trace_options[] = {
 #ifdef CONFIG_BRANCH_TRACER
         "branch",
 #endif
+        "annotate",
         NULL
 };
 
@@ -1113,6 +1115,7 @@ void tracing_stop_function_trace(void)
 
 enum trace_file_type {
         TRACE_FILE_LAT_FMT      = 1,
+        TRACE_FILE_ANNOTATE     = 2,
 };
 
 static void trace_iterator_increment(struct trace_iterator *iter, int cpu)
@@ -1532,6 +1535,12 @@ static void test_cpu_buff_start(struct trace_iterator *iter)
 {
         struct trace_seq *s = &iter->seq;
 
+        if (!(trace_flags & TRACE_ITER_ANNOTATE))
+                return;
+
+        if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
+                return;
+
         if (cpu_isset(iter->cpu, iter->started))
                 return;
 
@@ -2132,6 +2141,11 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)
         iter->trace = current_trace;
         iter->pos = -1;
 
+        /* Annotate start of buffers if we had overruns */
+        if (ring_buffer_overruns(iter->tr->buffer))
+                iter->iter_flags |= TRACE_FILE_ANNOTATE;
+
+
         for_each_tracing_cpu(cpu) {
 
                 iter->buffer_iter[cpu] =
@@ -2411,7 +2425,7 @@ static struct file_operations tracing_cpumask_fops = {
 };
 
 static ssize_t
-tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
+tracing_trace_options_read(struct file *filp, char __user *ubuf,
                        size_t cnt, loff_t *ppos)
 {
         char *buf;
@@ -2448,7 +2462,7 @@ tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
 }
 
 static ssize_t
-tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
+tracing_trace_options_write(struct file *filp, const char __user *ubuf,
                         size_t cnt, loff_t *ppos)
 {
         char buf[64];
@@ -2493,8 +2507,8 @@ tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
 
 static struct file_operations tracing_iter_fops = {
         .open           = tracing_open_generic,
-        .read           = tracing_iter_ctrl_read,
-        .write          = tracing_iter_ctrl_write,
+        .read           = tracing_trace_options_read,
+        .write          = tracing_trace_options_write,
 };
 
 static const char readme_msg[] =
@@ -2508,9 +2522,9 @@ static const char readme_msg[] =
         "# echo sched_switch > /debug/tracing/current_tracer\n"
         "# cat /debug/tracing/current_tracer\n"
         "sched_switch\n"
-        "# cat /debug/tracing/iter_ctrl\n"
+        "# cat /debug/tracing/trace_options\n"
         "noprint-parent nosym-offset nosym-addr noverbose\n"
-        "# echo print-parent > /debug/tracing/iter_ctrl\n"
+        "# echo print-parent > /debug/tracing/trace_options\n"
         "# echo 1 > /debug/tracing/tracing_enabled\n"
         "# cat /debug/tracing/trace > /tmp/trace.txt\n"
         "echo 0 > /debug/tracing/tracing_enabled\n"
@@ -2905,7 +2919,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf,
         char buf[64];
         int r;
 
-        r = sprintf(buf, "%lu\n", tr->entries);
+        r = sprintf(buf, "%lu\n", tr->entries >> 10);
         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
@@ -2945,6 +2959,9 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
                         atomic_inc(&max_tr.data[cpu]->disabled);
         }
 
+        /* value is in KB */
+        val <<= 10;
+
         if (val != global_trace.entries) {
                 ret = ring_buffer_resize(global_trace.buffer, val);
                 if (ret < 0) {
@@ -3145,10 +3162,10 @@ static __init int tracer_init_debugfs(void)
         if (!entry)
                 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
 
-        entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
+        entry = debugfs_create_file("trace_options", 0644, d_tracer,
                                     NULL, &tracing_iter_fops);
         if (!entry)
-                pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
+                pr_warning("Could not create debugfs 'trace_options' entry\n");
 
         entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
                                     NULL, &tracing_cpumask_fops);
@@ -3198,11 +3215,11 @@ static __init int tracer_init_debugfs(void)
                 pr_warning("Could not create debugfs "
                            "'trace_pipe' entry\n");
 
-        entry = debugfs_create_file("trace_entries", 0644, d_tracer,
+        entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer,
                                     &global_trace, &tracing_entries_fops);
         if (!entry)
                 pr_warning("Could not create debugfs "
-                           "'trace_entries' entry\n");
+                           "'buffer_size_kb' entry\n");
 
         entry = debugfs_create_file("trace_marker", 0220, d_tracer,
                                     NULL, &tracing_mark_fops);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9e015f5bea1..790ea8c0e1f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -473,6 +473,7 @@ enum trace_iterator_flags {
 #ifdef CONFIG_BRANCH_TRACER
         TRACE_ITER_BRANCH               = 0x1000,
 #endif
+        TRACE_ITER_ANNOTATE             = 0x2000,
 };
 
 /*