ring-buffer: Add integrity check at end of iter read (659f451f) · Commits · 戴 / test

kernel/trace/ring_buffer.c

+29 −0

Original line number	Diff line number	Diff line
		@@ -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);