From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Thu, 29 Nov 2012 03:17:32 +0000 (+1100)
Subject: mm: cma: WARN if freed memory is still in use
X-Git-Tag: next-20121205~1^2~282
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b4f615e971b155f5841b2697ff28ea7f204828b7;p=karo-tx-linux.git

mm: cma: WARN if freed memory is still in use

Memory returned to free_contig_range() must have no other references.  Let
kernel to complain loudly if page reference count is not equal to 1.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index dc2abffca944..5fc7a5d6d28e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5944,8 +5944,13 @@ done:
 
 void free_contig_range(unsigned long pfn, unsigned nr_pages)
 {
-	for (; nr_pages--; ++pfn)
-		__free_page(pfn_to_page(pfn));
+	struct page *page = pfn_to_page(pfn);
+	int count = 0;
+	for (; nr_pages--; page++) {
+		count += page_count(page) != 1;
+		__free_page(page);
+	}
+	WARN(count != 0, "%d pages are still in use!\n", count);
 }
 #endif