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 if (unlikely(next->prev != prev)) { 24 WARN(1, "list_add corruption. next->prev should be prev (%p), but was %p. (next=%p).\n", 25 prev, next->prev, next); 26 return false; 27 } 28 if (unlikely(prev->next != next)) { 29 WARN(1, "list_add corruption. prev->next should be next (%p), but was %p. (prev=%p).\n", 30 next, prev->next, prev); 31 return false; 32 } 33 if (unlikely(new == prev || new == next)) { 34 WARN(1, "list_add double add: new=%p, prev=%p, next=%p.\n", 35 new, prev, next); 36 return false; 37 } 38 return true; 39 } 40 EXPORT_SYMBOL(__list_add_valid); 41 42 bool __list_del_entry_valid(struct list_head *entry) 43 { 44 struct list_head *prev, *next; 45 46 prev = entry->prev; 47 next = entry->next; 48 49 if (unlikely(next == LIST_POISON1)) { 50 WARN(1, "list_del corruption, %p->next is LIST_POISON1 (%p)\n", 51 entry, LIST_POISON1); 52 return false; 53 } 54 if (unlikely(prev == LIST_POISON2)) { 55 WARN(1, "list_del corruption, %p->prev is LIST_POISON2 (%p)\n", 56 entry, LIST_POISON2); 57 return false; 58 } 59 if (unlikely(prev->next != entry)) { 60 WARN(1, "list_del corruption. prev->next should be %p, but was %p\n", 61 entry, prev->next); 62 return false; 63 } 64 if (unlikely(next->prev != entry)) { 65 WARN(1, "list_del corruption. next->prev should be %p, but was %p\n", 66 entry, next->prev); 67 return false; 68 } 69 return true; 70 71 } 72 EXPORT_SYMBOL(__list_del_entry_valid); 73