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

include/linux/list.h

+15 −0
Original line number Diff line number Diff line
@@ -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

lib/Kconfig.debug

+9 −0
Original line number Diff line number Diff line
@@ -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)

lib/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

lib/list_debug.c

0 → 100644
+77 −0
Original line number Diff line number Diff line 
/*

 * 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);