From: Cody P Schafer <cody@linux.vnet.ibm.com>
Date: Thu, 7 Feb 2013 01:27:05 +0000 (+1100)
Subject: mm/page_alloc: add a VM_BUG in __free_one_page() if the zone is uninitialized.
X-Git-Tag: next-20130218~1^2~332
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9a7486f0d245aaa24f3b08f6e322d71ac96a7677;p=karo-tx-linux.git

mm/page_alloc: add a VM_BUG in __free_one_page() if the zone is uninitialized.

Freeing pages to uninitialized zones is not handled by __free_one_page(),
and should never happen when the code is correct.

Ran into this while writing some code that dynamically onlines extra
zones.

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Hansen <dave@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c558decf6bac..cde32d2ffb9c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -538,6 +538,8 @@ static inline void __free_one_page(struct page *page,
 	unsigned long uninitialized_var(buddy_idx);
 	struct page *buddy;
 
+	VM_BUG_ON(!zone_is_initialized(zone));
+
 	if (unlikely(PageCompound(page)))
 		if (unlikely(destroy_compound_page(page, order)))
 			return;