From 0937502af7c9b648ed4e884ccb7f504b01a005a1 Mon Sep 17 00:00:00 2001
From: Christoph Lameter <clameter@sgi.com>
Date: Wed, 28 May 2008 10:32:22 -0700
Subject: [PATCH] slub: Add check for kfree() of non slab objects.

We can detect kfree()s on non slab objects by checking for PageCompound().
Works in the same way as for ksize. This helped me catch an invalid
kfree().

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---
 mm/slub.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/slub.c b/mm/slub.c
index 5f6e2c4a2ba..b3f2e713cdf 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2766,6 +2766,7 @@ void kfree(const void *x)
 
 	page = virt_to_head_page(x);
 	if (unlikely(!PageSlab(page))) {
+		BUG_ON(!PageCompound(page));
 		put_page(page);
 		return;
 	}
-- 
2.41.1