1 files changed, 57 insertions, 15 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ee8da93e91e0..944cd021aabf 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -119,7 +119,7 @@ enum ftrace_dump_mode ftrace_dump_on_oops;
 /* When set, tracing will stop when a WARN*() is hit */
 int __disable_trace_on_warning;
 
-static int tracing_set_tracer(const char *buf);
+static int tracing_set_tracer(struct trace_array *tr, const char *buf);
 
 #define MAX_TRACER_SIZE         100
 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
@@ -1231,7 +1231,7 @@ int register_tracer(struct tracer *type)
 
         printk(KERN_INFO "Starting tracer '%s'\n", type->name);
         /* Do we want this tracer to start on bootup? */
-        tracing_set_tracer(type->name);
+        tracing_set_tracer(&global_trace, type->name);
         default_bootup_tracer = NULL;
         /* disable other selftests, since this will break it. */
         tracing_selftest_disabled = true;
@@ -3122,27 +3122,52 @@ static int tracing_open(struct inode *inode, struct file *file)
         return ret;
 }
 
+/*
+ * Some tracers are not suitable for instance buffers.
+ * A tracer is always available for the global array (toplevel)
+ * or if it explicitly states that it is.
+ */
+static bool
+trace_ok_for_array(struct tracer *t, struct trace_array *tr)
+{
+        return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
+}
+
+/* Find the next tracer that this trace array may use */
+static struct tracer *
+get_tracer_for_array(struct trace_array *tr, struct tracer *t)
+{
+        while (t && !trace_ok_for_array(t, tr))
+                t = t->next;
+
+        return t;
+}
+
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
+        struct trace_array *tr = m->private;
         struct tracer *t = v;
 
         (*pos)++;
 
         if (t)
-                t = t->next;
+                t = get_tracer_for_array(tr, t->next);
 
         return t;
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
+        struct trace_array *tr = m->private;
         struct tracer *t;
         loff_t l = 0;
 
         mutex_lock(&trace_types_lock);
-        for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
-                ;
+
+        t = get_tracer_for_array(tr, trace_types);
+        for (; t && l < *pos; t = t_next(m, t, &l))
+                        ;
 
         return t;
 }
@@ -3177,10 +3202,21 @@ static const struct seq_operations show_traces_seq_ops = {
 
 static int show_traces_open(struct inode *inode, struct file *file)
 {
+        struct trace_array *tr = inode->i_private;
+        struct seq_file *m;
+        int ret;
+
         if (tracing_disabled)
                 return -ENODEV;
 
-        return seq_open(file, &show_traces_seq_ops);
+        ret = seq_open(file, &show_traces_seq_ops);
+        if (ret)
+                return ret;
+
+        m = file->private_data;
+        m->private = tr;
+
+        return 0;
 }
 
 static ssize_t
@@ -3871,10 +3907,9 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
 static void
 destroy_trace_option_files(struct trace_option_dentry *topts);
 
-static int tracing_set_tracer(const char *buf)
+static int tracing_set_tracer(struct trace_array *tr, const char *buf)
 {
         static struct trace_option_dentry *topts;
-        struct trace_array *tr = &global_trace;
         struct tracer *t;
 #ifdef CONFIG_TRACER_MAX_TRACE
         bool had_max_tr;
@@ -3902,6 +3937,12 @@ static int tracing_set_tracer(const char *buf)
         if (t == tr->current_trace)
                 goto out;
 
+        /* Some tracers are only allowed for the top level buffer */
+        if (!trace_ok_for_array(t, tr)) {
+                ret = -EINVAL;
+                goto out;
+        }
+
         trace_branch_disable();
 
         tr->current_trace->enabled = false;
@@ -3958,6 +3999,7 @@ static ssize_t
 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
                         size_t cnt, loff_t *ppos)
 {
+        struct trace_array *tr = filp->private_data;
         char buf[MAX_TRACER_SIZE+1];
         int i;
         size_t ret;
@@ -3977,7 +4019,7 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
         for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
                 buf[i] = 0;
 
-        err = tracing_set_tracer(buf);
+        err = tracing_set_tracer(tr, buf);
         if (err)
                 return err;
 
@@ -6193,6 +6235,12 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 {
         int cpu;
 
+        trace_create_file("available_tracers", 0444, d_tracer,
+                        tr, &show_traces_fops);
+
+        trace_create_file("current_tracer", 0644, d_tracer,
+                        tr, &set_tracer_fops);
+
         trace_create_file("tracing_cpumask", 0644, d_tracer,
                           tr, &tracing_cpumask_fops);
 
@@ -6245,12 +6293,6 @@ static __init int tracer_init_debugfs(void)
 
         init_tracer_debugfs(&global_trace, d_tracer);
 
-        trace_create_file("available_tracers", 0444, d_tracer,
-                        &global_trace, &show_traces_fops);
-
-        trace_create_file("current_tracer", 0644, d_tracer,
-                        &global_trace, &set_tracer_fops);
-
 #ifdef CONFIG_TRACER_MAX_TRACE
         trace_create_file("tracing_max_latency", 0644, d_tracer,
                         &tracing_max_latency, &tracing_max_lat_fops);