lib/list_debug.c

   1 /*
   2  * Copyright 2006, Red Hat, Inc., Dave Jones
   3  * Released under the General Public License (GPL).
   4  *
   5  * This file contains the linked list validation for DEBUG_LIST.
   6  */
   7
   8 #include <linux/export.h>
   9 #include <linux/list.h>
  10 #include <linux/bug.h>
  11 #include <linux/kernel.h>
  12 #include <linux/rculist.h>
  13
  14 /*
  15  * Check that the data structures for the list manipulations are reasonably
  16  * valid. Failures here indicate memory corruption (and possibly an exploit
  17  * attempt).
  18  */
  19
  20 bool __list_add_valid(struct list_head *new, struct list_head *prev,
  21                       struct list_head *next)
  22 {
  23         CHECK_DATA_CORRUPTION(next->prev != prev,
  24                 "list_add corruption. next->prev should be prev (%p), but was %p. (next=%p).\n",
  25                 prev, next->prev, next);
  26         CHECK_DATA_CORRUPTION(prev->next != next,
  27                 "list_add corruption. prev->next should be next (%p), but was %p. (prev=%p).\n",
  28                 next, prev->next, prev);
  29         CHECK_DATA_CORRUPTION(new == prev || new == next,
  30                 "list_add double add: new=%p, prev=%p, next=%p.\n",
  31                 new, prev, next);
  32
  33         return true;
  34 }
  35 EXPORT_SYMBOL(__list_add_valid);
  36
  37 bool __list_del_entry_valid(struct list_head *entry)
  38 {
  39         struct list_head *prev, *next;
  40
  41         prev = entry->prev;
  42         next = entry->next;
  43
  44         CHECK_DATA_CORRUPTION(next == LIST_POISON1,
  45                 "list_del corruption, %p->next is LIST_POISON1 (%p)\n",
  46                 entry, LIST_POISON1);
  47         CHECK_DATA_CORRUPTION(prev == LIST_POISON2,
  48                 "list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
  49                 entry, LIST_POISON2);
  50         CHECK_DATA_CORRUPTION(prev->next != entry,
  51                 "list_del corruption. prev->next should be %p, but was %p\n",
  52                 entry, prev->next);
  53         CHECK_DATA_CORRUPTION(next->prev != entry,
  54                 "list_del corruption. next->prev should be %p, but was %p\n",
  55                 entry, next->prev);
  56         return true;
  57
  58 }
  59 EXPORT_SYMBOL(__list_del_entry_valid);