ring-buffer: Fix crash due to uninitialized new_pages list head

The new_pages list head in the cpu_buffer is not initialized. When
adding pages to the ring buffer, if the memory allocation fails in
ring_buffer_resize, the clean up handler tries to free up the allocated
pages from all the cpu buffers. The panic is caused by referencing the
uninitialized new_pages list head.

Initializing the new_pages list head in rb_allocate_cpu_buffer fixes
this.

Link: http://lkml.kernel.org/r/1340391005-10880-1-git-send-email-vnagarnaik@google.com

Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1d0f6a8a0e5e..ba39cbabdc9f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1075,6 +1075,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
         rb_init_page(bpage->page);
 
         INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+        INIT_LIST_HEAD(&cpu_buffer->new_pages);
 
         ret = rb_allocate_pages(cpu_buffer, nr_pages);
         if (ret < 0)