From Manfred Spraul

A list_del debugging check.

Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 include/linux/list.h |    4 ++++
 1 files changed, 4 insertions(+)

diff -puN include/linux/list.h~list_del-debug include/linux/list.h
--- devel/include/linux/list.h~list_del-debug	2006-04-14 23:44:35.000000000 -0700
+++ devel-akpm/include/linux/list.h	2006-04-14 23:44:35.000000000 -0700
@@ -6,7 +6,9 @@
 #include <linux/stddef.h>
 #include <linux/poison.h>
 #include <linux/prefetch.h>
+#include <linux/kernel.h>
 #include <asm/system.h>
+#include <asm/bug.h>
 
 /*
  * Simple doubly linked list implementation.
@@ -155,6 +157,8 @@ static inline void __list_del(struct lis
  */
 static inline void list_del(struct list_head *entry)
 {
+	BUG_ON(entry->prev->next != entry);
+	BUG_ON(entry->next->prev != entry);
 	__list_del(entry->prev, entry->next);
 	entry->next = LIST_POISON1;
 	entry->prev = LIST_POISON2;
_