2 files changed, 9 insertions, 8 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index b0702ff78218..1da7b6ea8b85 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3902,12 +3902,12 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
         ret = read;
 
         cpu_buffer->lost_events = 0;
+
+        commit = local_read(&bpage->commit);
         /*
          * Set a flag in the commit field if we lost events
          */
         if (missed_events) {
-                commit = local_read(&bpage->commit);
-
                 /* If there is room at the end of the page to save the
                  * missed events, then record it there.
                  */
@@ -3915,10 +3915,17 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
                         memcpy(&bpage->data[commit], &missed_events,
                                sizeof(missed_events));
                         local_add(RB_MISSED_STORED, &bpage->commit);
+                        commit += sizeof(missed_events);
                 }
                 local_add(RB_MISSED_EVENTS, &bpage->commit);
         }
 
+        /*
+         * This page may be off to user land. Zero it out here.
+         */
+        if (commit < BUF_PAGE_SIZE)
+                memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
+
  out_unlock:
         spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ba0ec81158b2..95d0b1a28f93 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3661,7 +3661,6 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
                      size_t count, loff_t *ppos)
 {
         struct ftrace_buffer_info *info = filp->private_data;
-        unsigned int pos;
         ssize_t ret;
         size_t size;
 
@@ -3688,11 +3687,6 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
         if (ret < 0)
                 return 0;
 
-        pos = ring_buffer_page_len(info->spare);
-
-        if (pos < PAGE_SIZE)
-                memset(info->spare + pos, 0, PAGE_SIZE - pos);
-
 read:
         size = PAGE_SIZE - info->read;
         if (size > count)