Merge tag 'trace-fixes-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Oleg is working on fixing a very tight race between opening a event
  file and deleting that event at the same time (both must be done as
  root).

  I also found a bug while testing Oleg's patches which has to do with a
  race with kprobes using the function tracer.

  There's also a deadlock fix that was introduced with the previous
  fixes"

* tag 'trace-fixes-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Remove locking trace_types_lock from tracing_reset_all_online_cpus()
  ftrace: Add check for NULL regs if ops has SAVE_REGS set
  tracing: Kill trace_cpu struct/members
  tracing: Change tracing_fops/snapshot_fops to rely on tracing_get_cpu()
  tracing: Change tracing_entries_fops to rely on tracing_get_cpu()
  tracing: Change tracing_stats_fops to rely on tracing_get_cpu()
  tracing: Change tracing_buffers_fops to rely on tracing_get_cpu()
  tracing: Change tracing_pipe_fops() to rely on tracing_get_cpu()
  tracing: Introduce trace_create_cpu_file() and tracing_get_cpu()

3 files changed, 95 insertions, 128 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 67708f46baae..8ce9eefc5bb4 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1441,12 +1441,22 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
  * the hashes are freed with call_rcu_sched().
  */
 static int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
         struct ftrace_hash *filter_hash;
         struct ftrace_hash *notrace_hash;
         int ret;
 
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+        /*
+         * There's a small race when adding ops that the ftrace handler
+         * that wants regs, may be called without them. We can not
+         * allow that handler to be called if regs is NULL.
+         */
+        if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
+                return 0;
+#endif
+
         filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
         notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
 
@@ -4218,7 +4228,7 @@ static inline void ftrace_startup_enable(int command) { }
 # define ftrace_shutdown_sysctl()       do { } while (0)
 
 static inline int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
         return 1;
 }
@@ -4241,7 +4251,7 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
         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))
+                    ftrace_ops_test(op, ip, regs))
                         op->func(ip, parent_ip, op, regs);
         } while_for_each_ftrace_op(op);
         trace_recursion_clear(TRACE_CONTROL_BIT);
@@ -4274,7 +4284,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
          */
         preempt_disable_notrace();
         do_for_each_ftrace_op(op, ftrace_ops_list) {
-                if (ftrace_ops_test(op, ip))
+                if (ftrace_ops_test(op, ip, regs))
                         op->func(ip, parent_ip, op, regs);
         } while_for_each_ftrace_op(op);
         preempt_enable_notrace();
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3f2477713aca..882ec1dd1515 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1224,18 +1224,17 @@ void tracing_reset_current(int cpu)
         tracing_reset(&global_trace.trace_buffer, cpu);
 }
 
+/* Must have trace_types_lock held */
 void tracing_reset_all_online_cpus(void)
 {
         struct trace_array *tr;
 
-        mutex_lock(&trace_types_lock);
         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
                 tracing_reset_online_cpus(&tr->trace_buffer);
 #ifdef CONFIG_TRACER_MAX_TRACE
                 tracing_reset_online_cpus(&tr->max_buffer);
 #endif
         }
-        mutex_unlock(&trace_types_lock);
 }
 
 #define SAVED_CMDLINES 128
@@ -2843,6 +2842,17 @@ static int s_show(struct seq_file *m, void *v)
         return 0;
 }
 
+/*
+ * Should be used after trace_array_get(), trace_types_lock
+ * ensures that i_cdev was already initialized.
+ */
+static inline int tracing_get_cpu(struct inode *inode)
+{
+        if (inode->i_cdev) /* See trace_create_cpu_file() */
+                return (long)inode->i_cdev - 1;
+        return RING_BUFFER_ALL_CPUS;
+}
+
 static const struct seq_operations tracer_seq_ops = {
         .start          = s_start,
         .next           = s_next,
@@ -2851,9 +2861,9 @@ static const struct seq_operations tracer_seq_ops = {
 };
 
 static struct trace_iterator *
-__tracing_open(struct trace_array *tr, struct trace_cpu *tc,
-               struct inode *inode, struct file *file, bool snapshot)
+__tracing_open(struct inode *inode, struct file *file, bool snapshot)
 {
+        struct trace_array *tr = inode->i_private;
         struct trace_iterator *iter;
         int cpu;
 
@@ -2894,8 +2904,8 @@ __tracing_open(struct trace_array *tr, struct trace_cpu *tc,
                 iter->trace_buffer = &tr->trace_buffer;
         iter->snapshot = snapshot;
         iter->pos = -1;
+        iter->cpu_file = tracing_get_cpu(inode);
         mutex_init(&iter->mutex);
-        iter->cpu_file = tc->cpu;
 
         /* Notify the tracer early; before we stop tracing. */
         if (iter->trace && iter->trace->open)
@@ -2971,44 +2981,22 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
         filp->private_data = inode->i_private;
 
         return 0;
-        
-}
-
-static int tracing_open_generic_tc(struct inode *inode, struct file *filp)
-{
-        struct trace_cpu *tc = inode->i_private;
-        struct trace_array *tr = tc->tr;
-
-        if (tracing_disabled)
-                return -ENODEV;
-
-        if (trace_array_get(tr) < 0)
-                return -ENODEV;
-
-        filp->private_data = inode->i_private;
-
-        return 0;
-        
 }
 
 static int tracing_release(struct inode *inode, struct file *file)
 {
+        struct trace_array *tr = inode->i_private;
         struct seq_file *m = file->private_data;
         struct trace_iterator *iter;
-        struct trace_array *tr;
         int cpu;
 
-        /* Writes do not use seq_file, need to grab tr from inode */
         if (!(file->f_mode & FMODE_READ)) {
-                struct trace_cpu *tc = inode->i_private;
-
-                trace_array_put(tc->tr);
+                trace_array_put(tr);
                 return 0;
         }
 
+        /* Writes do not use seq_file */