[PATCH 1/2] ring-buffer: Fix crash due to uninitialized new_pages list head

[Steven Rostedt]

From: Vaibhav Nagarnaik <vnagarnaik@xxxxxxxxxx>

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@xxxxxxxxxx

Cc: Justin Teravest <teravest@xxxxxxxxxx>
Cc: David Sharp <dhsharp@xxxxxxxxxx>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 kernel/trace/ring_buffer.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1d0f6a8..ba39cba 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)
-- 
1.7.10

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