Merge tag 'trace-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing update from Steven Rostedt:
 "This batch of changes is mostly clean ups and small bug fixes.  The
  only real feature that was added this release is from Namhyung Kim,
  who introduced "set_graph_notrace" filter that lets you run the
  function graph tracer and not trace particular functions and their
  call chain.

  Tom Zanussi added some updates to the ftrace multibuffer tracing that
  made it more consistent with the top level tracing.

  One of the fixes for perf function tracing required an API change in
  RCU; the addition of "rcu_is_watching()".  As Paul McKenney is pushing
  that change in this release too, he gave me a branch that included all
  the changes to get that working, and I pulled that into my tree in
  order to complete the perf function tracing fix"

* tag 'trace-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Add rcu annotation for syscall trace descriptors
  tracing: Do not use signed enums with unsigned long long in fgragh output
  tracing: Remove unused function ftrace_off_permanent()
  tracing: Do not assign filp->private_data to freed memory
  tracing: Add helper function tracing_is_disabled()
  tracing: Open tracer when ftrace_dump_on_oops is used
  tracing: Add support for SOFT_DISABLE to syscall events
  tracing: Make register/unregister_ftrace_command __init
  tracing: Update event filters for multibuffer
  recordmcount.pl: Add support for __fentry__
  ftrace: Have control op function callback only trace when RCU is watching
  rcu: Do not trace rcu_is_watching() functions
  ftrace/x86: skip over the breakpoint for ftrace caller
  trace/trace_stat: use rbtree postorder iteration helper instead of opencoding
  ftrace: Add set_graph_notrace filter
  ftrace: Narrow down the protected area of graph_lock
  ftrace: Introduce struct ftrace_graph_data
  ftrace: Get rid of ftrace_graph_filter_enabled
  tracing: Fix potential out-of-bounds in trace_get_user()
  tracing: Show more exact help information about snapshot

1 files changed, 123 insertions, 38 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 03cf44ac54d3..22fa55696760 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3307,7 +3307,11 @@ void unregister_ftrace_function_probe_all(char *glob)
 static LIST_HEAD(ftrace_commands);
 static DEFINE_MUTEX(ftrace_cmd_mutex);
 
-int register_ftrace_command(struct ftrace_func_command *cmd)
+/*
+ * Currently we only register ftrace commands from __init, so mark this
+ * __init too.
+ */
+__init int register_ftrace_command(struct ftrace_func_command *cmd)
 {
         struct ftrace_func_command *p;
         int ret = 0;
@@ -3326,7 +3330,11 @@ int register_ftrace_command(struct ftrace_func_command *cmd)
         return ret;
 }
 
-int unregister_ftrace_command(struct ftrace_func_command *cmd)
+/*
+ * Currently we only unregister ftrace commands from __init, so mark
+ * this __init too.
+ */
+__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
 {
         struct ftrace_func_command *p, *n;
         int ret = -ENODEV;
@@ -3641,7 +3649,7 @@ __setup("ftrace_filter=", set_ftrace_filter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
-static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
+static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
 
 static int __init set_graph_function(char *str)
 {
@@ -3659,7 +3667,7 @@ static void __init set_ftrace_early_graph(char *buf)
                 func = strsep(&buf, ",");
                 /* we allow only one expression at a time */
                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                      func);
+                                      FTRACE_GRAPH_MAX_FUNCS, func);
                 if (ret)
                         printk(KERN_DEBUG "ftrace: function %s not "
                                           "traceable\n", func);
@@ -3776,15 +3784,25 @@ static const struct file_operations ftrace_notrace_fops = {
 static DEFINE_MUTEX(graph_lock);
 
 int ftrace_graph_count;
-int ftrace_graph_filter_enabled;
+int ftrace_graph_notrace_count;
 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+
+struct ftrace_graph_data {
+        unsigned long *table;
+        size_t size;
+        int *count;
+        const struct seq_operations *seq_ops;
+};
 
 static void *
 __g_next(struct seq_file *m, loff_t *pos)
 {
-        if (*pos >= ftrace_graph_count)
+        struct ftrace_graph_data *fgd = m->private;
+
+        if (*pos >= *fgd->count)
                 return NULL;
-        return &ftrace_graph_funcs[*pos];
+        return &fgd->table[*pos];
 }
 
 static void *
@@ -3796,10 +3814,12 @@ g_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *g_start(struct seq_file *m, loff_t *pos)
 {
+        struct ftrace_graph_data *fgd = m->private;
+
         mutex_lock(&graph_lock);
 
         /* Nothing, tell g_show to print all functions are enabled */
-        if (!ftrace_graph_filter_enabled && !*pos)
+        if (!*fgd->count && !*pos)
                 return (void *)1;
 
         return __g_next(m, pos);
@@ -3835,38 +3855,88 @@ static const struct seq_operations ftrace_graph_seq_ops = {
 };
 
 static int
-ftrace_graph_open(struct inode *inode, struct file *file)
+__ftrace_graph_open(struct inode *inode, struct file *file,
+                    struct ftrace_graph_data *fgd)
 {
         int ret = 0;
 
-        if (unlikely(ftrace_disabled))
-                return -ENODEV;
-
         mutex_lock(&graph_lock);
         if ((file->f_mode & FMODE_WRITE) &&
             (file->f_flags & O_TRUNC)) {
-                ftrace_graph_filter_enabled = 0;
-                ftrace_graph_count = 0;
-                memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
+                *fgd->count = 0;
+                memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
         }
         mutex_unlock(&graph_lock);
 
-        if (file->f_mode & FMODE_READ)
-                ret = seq_open(file, &ftrace_graph_seq_ops);
+        if (file->f_mode & FMODE_READ) {
+                ret = seq_open(file, fgd->seq_ops);
+                if (!ret) {
+                        struct seq_file *m = file->private_data;
+                        m->private = fgd;
+                }
+        } else
+                file->private_data = fgd;
 
         return ret;
 }
 
 static int
+ftrace_graph_open(struct inode *inode, struct file *file)
+{
+        struct ftrace_graph_data *fgd;
+
+        if (unlikely(ftrace_disabled))
+                return -ENODEV;
+
+        fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+        if (fgd == NULL)
+                return -ENOMEM;
+
+        fgd->table = ftrace_graph_funcs;
+        fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+        fgd->count = &ftrace_graph_count;
+        fgd->seq_ops = &ftrace_graph_seq_ops;
+
+        return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
+ftrace_graph_notrace_open(struct inode *inode, struct file *file)
+{
+        struct ftrace_graph_data *fgd;
+
+        if (unlikely(ftrace_disabled))
+                return -ENODEV;
+
+        fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+        if (fgd == NULL)
+                return -ENOMEM;
+
+        fgd->table = ftrace_graph_notrace_funcs;
+        fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+        fgd->count = &ftrace_graph_notrace_count;
+        fgd->seq_ops = &ftrace_graph_seq_ops;
+
+        return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
 ftrace_graph_release(struct inode *inode, struct file *file)
 {
-        if (file->f_mode & FMODE_READ)
+        if (file->f_mode & FMODE_READ) {
+                struct seq_file *m = file->private_data;
+
+                kfree(m->private);
                 seq_release(inode, file);
+        } else {
+                kfree(file->private_data);
+        }
+
         return 0;
 }
 
 static int
-ftrace_set_func(unsigned long *array, int *idx, char *buffer)
+ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
 {
         struct dyn_ftrace *rec;
         struct ftrace_page *pg;
@@ -3879,7 +3949,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 
         /* decode regex */
         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
-        if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
+        if (!not && *idx >= size)
                 return -EBUSY;
 
         search_len = strlen(search);
@@ -3907,7 +3977,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
                                 fail = 0;
                                 if (!exists) {
                                         array[(*idx)++] = rec->ip;
-                                        if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
+                                        if (*idx >= size)
                                                 goto out;
                                 }
                         } else {
@@ -3925,8 +3995,6 @@ out:
         if (fail)
                 return -EINVAL;
 
-        ftrace_graph_filter_enabled = !!(*idx);
-
         return 0;
 }
 
@@ -3935,36 +4003,33 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
                    size_t cnt, loff_t *ppos)
 {
         struct trace_parser parser;
-        ssize_t read, ret;
+        ssize_t read, ret = 0;
+        struct ftrace_graph_data *fgd = file->private_data;
 
         if (!cnt)
                 return 0;
 
-        mutex_lock(&graph_lock);
-
-        if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
-                ret = -ENOMEM;
-                goto out_unlock;
-        }
+        if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
+                return -ENOMEM;
 
         read = trace_get_user(&parser, ubuf, cnt, ppos);
 
         if (read >= 0 && trace_parser_loaded((&parser))) {
                 parser.buffer[parser.idx] = 0;
 
+                mutex_lock(&graph_lock);
+
                 /* we allow only one expression at a time */
-                ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                        parser.buffer);
-                if (ret)
-                        goto out_free;
+                ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
+                                      parser.buffer);
+
+                mutex_unlock(&graph_lock);
         }
 
-        ret = read;
+        if (!ret)
+                ret = read;
 
-out_free:
         trace_parser_put(&parser);
-out_unlock:
-        mutex_unlock(&graph_lock);
 
         return ret;
 }
@@ -3976,6 +4041,14 @@ static const struct file_operations ftrace_graph_fops = {
         .llseek         = ftrace_filter_lseek,
         .release        = ftrace_graph_release,
 };
+
+static const struct file_operations ftrace_graph_notrace_fops = {
+        .open           = ftrace_graph_notrace_open,
+        .read           = seq_read,
+        .write          = ftrace_graph_write,
+        .llseek         = ftrace_filter_lseek,
+        .release        = ftrace_graph_release,
+};
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
@@ -3997,6 +4070,9 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
         trace_create_file("set_graph_function", 0444, d_tracer,
                                     NULL,
                                     &ftrace_graph_fops);
+        trace_create_file("set_graph_notrace", 0444, d_tracer,
+                                    NULL,
+                                    &ftrace_graph_notrace_fops);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
         return 0;
@@ -4320,12 +4396,21 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
          */
         preempt_disable_notrace();
         trace_recursion_set(TRACE_CONTROL_BIT);
+
+        /*
+         * Control funcs (perf) uses RCU. Only trace if
+         * RCU is currently active.
+         */
+        if (!rcu_is_watching())
+                goto out;
+
         do_for_each_ftrace_op(op, ftrace_control_list) {
                 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
                     !ftrace_function_local_disabled(op) &&
                     ftrace_ops_test(op, ip, regs))
                         op->func(ip, parent_ip, op, regs);
         } while_for_each_ftrace_op(op);
+ out:
         trace_recursion_clear(TRACE_CONTROL_BIT);
         preempt_enable_notrace();
 }