ring-buffer: check for failed allocation in ring buffer benchmark

The result of the allocation of the ring buffer read page in the
ring buffer bench mark does not check the return to see if a page
was actually allocated. This patch fixes that.

[ Impact: avoid NULL dereference ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 747244acb8fdb0168802fb81e5280fdbf9a39d62..dcd75e9e49f443d531c1031c3527ab6d55eeefd0 100644 (file)
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -84,6 +84,9 @@ static enum event_status read_page(int cpu)
        int i;
 
        bpage = ring_buffer_alloc_read_page(buffer);
+       if (!bpage)
+               return EVENT_DROPPED;
+
        ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
        if (ret >= 0) {
                rpage = bpage;