1 files changed, 29 insertions, 0 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index d673ef03d16d..e0573c523b5c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1599,6 +1599,29 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
         }
 
  out:
+        /*
+         * The ring buffer resize can happen with the ring buffer
+         * enabled, so that the update disturbs the tracing as little
+         * as possible. But if the buffer is disabled, we do not need
+         * to worry about that, and we can take the time to verify
+         * that the buffer is not corrupt.
+         */
+        if (atomic_read(&buffer->record_disabled)) {
+                atomic_inc(&buffer->record_disabled);
+                /*
+                 * Even though the buffer was disabled, we must make sure
+                 * that it is truly disabled before calling rb_check_pages.
+                 * There could have been a race between checking
+                 * record_disable and incrementing it.
+                 */
+                synchronize_sched();
+                for_each_buffer_cpu(buffer, cpu) {
+                        cpu_buffer = buffer->buffers[cpu];
+                        rb_check_pages(cpu_buffer);
+                }
+                atomic_dec(&buffer->record_disabled);
+        }
+
         mutex_unlock(&buffer->mutex);
         return size;
 
@@ -3750,6 +3773,12 @@ ring_buffer_read_finish(struct ring_buffer_iter *iter)
 {
         struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
 
+        /*
+         * Ring buffer is disabled from recording, here's a good place
+         * to check the integrity of the ring buffer. 
+         */
+        rb_check_pages(cpu_buffer);
+
         atomic_dec(&cpu_buffer->record_disabled);
         atomic_dec(&cpu_buffer->buffer->resize_disabled);
         kfree(iter);