1 files changed, 11 insertions, 4 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1bbfa0446507..3c13e46d7d24 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3454,7 +3454,7 @@ static int tracing_wait_pipe(struct file *filp)
                         return -EINTR;
 
                 /*
-                 * We block until we read something and tracing is enabled.
+                 * We block until we read something and tracing is disabled.
                  * We still block if tracing is disabled, but we have never
                  * read anything. This allows a user to cat this file, and
                  * then enable tracing. But after we have read something,
@@ -3462,7 +3462,7 @@ static int tracing_wait_pipe(struct file *filp)
                  *
                  * iter->pos will be 0 if we haven't read anything.
                  */
-                if (tracing_is_enabled() && iter->pos)
+                if (!tracing_is_enabled() && iter->pos)
                         break;
         }
 
@@ -4817,10 +4817,17 @@ rb_simple_write(struct file *filp, const char __user *ubuf,
                 return ret;
 
         if (buffer) {
-                if (val)
+                mutex_lock(&trace_types_lock);
+                if (val) {
                         ring_buffer_record_on(buffer);
-                else
+                        if (current_trace->start)
+                                current_trace->start(tr);
+                } else {
                         ring_buffer_record_off(buffer);
+                        if (current_trace->stop)
+                                current_trace->stop(tr);
+                }
+                mutex_unlock(&trace_types_lock);
         }
 
         (*ppos)++;