slob: fix lockup in slob_free()
Don't hold SLOB lock when freeing the page. Reduces lock hold width. See
the following thread for discussion of the bug:
http://marc.info/?l=linux-kernel&m=123709983214143&w=2
Reported-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
diff --git a/mm/slob.c b/mm/slob.c
index bf7e8fc..f901653 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -393,10 +393,11 @@
/* Go directly to page allocator. Do not pass slob allocator */
if (slob_page_free(sp))
clear_slob_page_free(sp);
+ spin_unlock_irqrestore(&slob_lock, flags);
clear_slob_page(sp);
free_slob_page(sp);
free_page((unsigned long)b);
- goto out;
+ return;
}
if (!slob_page_free(sp)) {