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Commit 559f9bad authored by Dave Jones's avatar Dave Jones Committed by Paul E. McKenney
Browse files

rcu: List-debug variants of rcu list routines. 



* Make __list_add_rcu check the next->prev and prev->next pointers
  just like __list_add does.
* Make list_del_rcu use __list_del_entry, which does the same checking
  at deletion time.

Has been running for a week here without anything being tripped up,
but it seems worth adding for completeness just in case something
ever does corrupt those lists.

Signed-off-by: default avatarDave Jones <davej@redhat.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 66f75a5d

include/linux/rculist.h

+6 −1
Original line number Original line Diff line number Diff line
@@ -30,6 +30,7 @@ 
 * This is only for internal list manipulation where we know

 * This is only for internal list manipulation where we know

 * the prev/next entries already!

 * the prev/next entries already!

 */

 */

#ifndef CONFIG_DEBUG_LIST

static inline void __list_add_rcu(struct list_head *new,

static inline void __list_add_rcu(struct list_head *new,

		struct list_head *prev, struct list_head *next)

		struct list_head *prev, struct list_head *next)

{

{
@@ -38,6 +39,10 @@ static inline void __list_add_rcu(struct list_head *new, 
	rcu_assign_pointer(list_next_rcu(prev), new);

	rcu_assign_pointer(list_next_rcu(prev), new);

	next->prev = new;

	next->prev = new;

}

}

#else

extern void __list_add_rcu(struct list_head *new,

		struct list_head *prev, struct list_head *next);

#endif





/**

/**

 * list_add_rcu - add a new entry to rcu-protected list

 * list_add_rcu - add a new entry to rcu-protected list
@@ -108,7 +113,7 @@ static inline void list_add_tail_rcu(struct list_head *new, 
 */

 */

static inline void list_del_rcu(struct list_head *entry)

static inline void list_del_rcu(struct list_head *entry)

{

{

	__list_del(entry->prev, entry->next);

	__list_del_entry(entry);

	entry->prev = LIST_POISON2;

	entry->prev = LIST_POISON2;

}

}

lib/list_debug.c

+22 −0
Original line number Original line Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/list.h>

#include <linux/list.h>

#include <linux/bug.h>

#include <linux/bug.h>

#include <linux/kernel.h>

#include <linux/kernel.h>

#include <linux/rculist.h>





/*

/*

 * Insert a new entry between two known consecutive entries.

 * Insert a new entry between two known consecutive entries.
@@ -75,3 +76,24 @@ void list_del(struct list_head *entry) 
	entry->prev = LIST_POISON2;

	entry->prev = LIST_POISON2;

}

}

EXPORT_SYMBOL(list_del);

EXPORT_SYMBOL(list_del);



/*

 * RCU variants.

 */

void __list_add_rcu(struct list_head *new,

		    struct list_head *prev, struct list_head *next)

{

	WARN(next->prev != prev,

		"list_add_rcu corruption. next->prev should be "

		"prev (%p), but was %p. (next=%p).\n",

		prev, next->prev, next);

	WARN(prev->next != next,

		"list_add_rcu corruption. prev->next should be "

		"next (%p), but was %p. (prev=%p).\n",

		next, prev->next, prev);

	new->next = next;

	new->prev = prev;

	rcu_assign_pointer(list_next_rcu(prev), new);

	next->prev = new;

}

EXPORT_SYMBOL(__list_add_rcu);