On Fri, Dec 18, 2015 at 01:59:13PM -0700, Mathieu Poirier wrote:

+static void etb_update_buffer(struct coresight_device *csdev,
+			      struct perf_output_handle *handle,
+			      void *sink_config)
+{
+	int i, cur;
+	u32 *buf_ptr;

...

+	for (i = 0; i < to_read; i += 4) {
+		buf_ptr = buf->data_pages[cur] + offset;
+		read_data = readl_relaxed(drvdata->base +
+					  ETB_RAM_READ_DATA_REG);
+		*buf_ptr++ = read_data >> 0;
+		*buf_ptr++ = read_data >> 8;
+		*buf_ptr++ = read_data >> 16;
+		*buf_ptr++ = read_data >> 24;

buf_ptr should either be changed to a u8* or just the first write should
be present.  Otherwise this overwrites lots of memory.

+
+		offset += 4;
+		if (offset >= PAGE_SIZE) {