Commit 199a9afc authored by Dave Jones's avatar Dave Jones Committed by Linus Torvalds
Browse files

[PATCH] Debug variants of linked list macros


Signed-off-by: default avatarDave Jones <davej@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent df67b3da
......@@ -39,6 +39,7 @@ static inline void INIT_LIST_HEAD(struct list_head *list)
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
#ifndef CONFIG_DEBUG_LIST
static inline void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next)
......@@ -48,6 +49,11 @@ static inline void __list_add(struct list_head *new,
new->prev = prev;
prev->next = new;
}
#else
extern void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next);
#endif
/**
* list_add - add a new entry
......@@ -57,10 +63,15 @@ static inline void __list_add(struct list_head *new,
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*/
#ifndef CONFIG_DEBUG_LIST
static inline void list_add(struct list_head *new, struct list_head *head)
{
__list_add(new, head, head->next);
}
#else
extern void list_add(struct list_head *new, struct list_head *head);
#endif
/**
* list_add_tail - add a new entry
......@@ -153,12 +164,16 @@ static inline void __list_del(struct list_head * prev, struct list_head * next)
* Note: list_empty on entry does not return true after this, the entry is
* in an undefined state.
*/
#ifndef CONFIG_DEBUG_LIST
static inline void list_del(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
entry->next = LIST_POISON1;
entry->prev = LIST_POISON2;
}
#else
extern void list_del(struct list_head *entry);
#endif
/**
* list_del_rcu - deletes entry from list without re-initialization
......
......@@ -320,6 +320,15 @@ config DEBUG_VM
If unsure, say N.
config DEBUG_LIST
bool "Debug linked list manipulation"
depends on DEBUG_KERNEL
help
Enable this to turn on extended checks in the linked-list
walking routines.
If unsure, say N.
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH)
......
......@@ -28,6 +28,7 @@ lib-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
obj-$(CONFIG_PLIST) += plist.o
obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
obj-$(CONFIG_DEBUG_LIST) += list_debug.o
ifneq ($(CONFIG_HAVE_DEC_LOCK),y)
lib-y += dec_and_lock.o
......
/*
* Copyright 2006, Red Hat, Inc., Dave Jones
* Released under the General Public License (GPL).
*
* This file contains the linked list implementations for
* DEBUG_LIST.
*/
#include <linux/module.h>
#include <linux/list.h>
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next)
{
if (unlikely(next->prev != prev)) {
printk(KERN_ERR "list_add corruption. next->prev should be %p, but was %p\n",
prev, next->prev);
BUG();
}
if (unlikely(prev->next != next)) {
printk(KERN_ERR "list_add corruption. prev->next should be %p, but was %p\n",
next, prev->next);
BUG();
}
next->prev = new;
new->next = next;
new->prev = prev;
prev->next = new;
}
EXPORT_SYMBOL(__list_add);
/**
* list_add - add a new entry
* @new: new entry to be added
* @head: list head to add it after
*
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*/
void list_add(struct list_head *new, struct list_head *head)
{
__list_add(new, head, head->next);
}
EXPORT_SYMBOL(list_add);
/**
* list_del - deletes entry from list.
* @entry: the element to delete from the list.
* Note: list_empty on entry does not return true after this, the entry is
* in an undefined state.
*/
void list_del(struct list_head *entry)
{
if (unlikely(entry->prev->next != entry)) {
printk(KERN_ERR "list_del corruption. prev->next should be %p, but was %p\n",
entry, entry->prev->next);
BUG();
}
if (unlikely(entry->next->prev != entry)) {
printk(KERN_ERR "list_del corruption. next->prev should be %p, but was %p\n",
entry, entry->next->prev);
BUG();
}
__list_del(entry->prev, entry->next);
entry->next = LIST_POISON1;
entry->prev = LIST_POISON2;
}
EXPORT_SYMBOL(list_del);
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