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authorSteven Rostedt <srostedt@redhat.com>2012-05-17 01:46:32 +0200
committerSteven Rostedt <rostedt@goodmis.org>2012-05-17 01:50:36 +0200
commit308f7eeb7882c27c1d7aa783499cb22f3b199718 (patch)
treef04fb171bae7d2b2f1a7566bd747724a4973014f /kernel/trace
parentring-buffer: Add integrity check at end of iter read (diff)
downloadlinux-308f7eeb7882c27c1d7aa783499cb22f3b199718.tar.xz
linux-308f7eeb7882c27c1d7aa783499cb22f3b199718.zip
ring-buffer: Reset head page before running self test
When the ring buffer does its consistency test on itself, it removes the head page, runs the tests, and then adds it back to what the "head_page" pointer was. But because the head_page pointer may lack behind the real head page (held by the link list pointer). The reset may be incorrect. Instead, if the head_page exists (it does not on first allocation) reset it back to the real head page before running the consistency tests. Then it will be put back to its original location after the tests are complete. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ring_buffer.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index e0573c523b5c..68388f876d43 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -945,6 +945,10 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
struct list_head *head = cpu_buffer->pages;
struct buffer_page *bpage, *tmp;
+ /* Reset the head page if it exists */
+ if (cpu_buffer->head_page)
+ rb_set_head_page(cpu_buffer);
+
rb_head_page_deactivate(cpu_buffer);
if (RB_WARN_ON(cpu_buffer, head->next->prev != head))