diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 15 | ||||
| -rw-r--r-- | lib/list_debug.c | 99 |
2 files changed, 42 insertions, 72 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a6c8db1d62f6..9bb7d825ba14 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1218,7 +1218,7 @@ config DEBUG_BUGVERBOSE config DEBUG_LIST bool "Debug linked list manipulation" - depends on DEBUG_KERNEL + depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION help Enable this to turn on extended checks in the linked-list walking routines. @@ -1434,7 +1434,8 @@ config RCU_TRACE select TRACE_CLOCK help This option provides tracing in RCU which presents stats - in debugfs for debugging RCU implementation. + in debugfs for debugging RCU implementation. It also enables + additional tracepoints for ftrace-style event tracing. Say Y here if you want to enable RCU tracing Say N if you are unsure. @@ -1964,6 +1965,16 @@ config TEST_STATIC_KEYS If unsure, say N. +config BUG_ON_DATA_CORRUPTION + bool "Trigger a BUG when data corruption is detected" + select DEBUG_LIST + help + Select this option if the kernel should BUG when it encounters + data corruption in kernel memory structures when they get checked + for validity. + + If unsure, say N. + source "samples/Kconfig" source "lib/Kconfig.kgdb" diff --git a/lib/list_debug.c b/lib/list_debug.c index 3859bf63561c..7f7bfa55eb6d 100644 --- a/lib/list_debug.c +++ b/lib/list_debug.c @@ -2,8 +2,7 @@ * Copyright 2006, Red Hat, Inc., Dave Jones * Released under the General Public License (GPL). * - * This file contains the linked list implementations for - * DEBUG_LIST. + * This file contains the linked list validation for DEBUG_LIST. */ #include <linux/export.h> @@ -13,88 +12,48 @@ #include <linux/rculist.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! + * Check that the data structures for the list manipulations are reasonably + * valid. Failures here indicate memory corruption (and possibly an exploit + * attempt). */ -void __list_add(struct list_head *new, - struct list_head *prev, - struct list_head *next) +bool __list_add_valid(struct list_head *new, struct list_head *prev, + struct list_head *next) { - WARN(next->prev != prev, - "list_add corruption. next->prev should be " - "prev (%p), but was %p. (next=%p).\n", + CHECK_DATA_CORRUPTION(next->prev != prev, + "list_add corruption. next->prev should be prev (%p), but was %p. (next=%p).\n", prev, next->prev, next); - WARN(prev->next != next, - "list_add corruption. prev->next should be " - "next (%p), but was %p. (prev=%p).\n", + CHECK_DATA_CORRUPTION(prev->next != next, + "list_add corruption. prev->next should be next (%p), but was %p. (prev=%p).\n", next, prev->next, prev); - WARN(new == prev || new == next, - "list_add double add: new=%p, prev=%p, next=%p.\n", - new, prev, next); - next->prev = new; - new->next = next; - new->prev = prev; - WRITE_ONCE(prev->next, new); + CHECK_DATA_CORRUPTION(new == prev || new == next, + "list_add double add: new=%p, prev=%p, next=%p.\n", + new, prev, next); + + return true; } -EXPORT_SYMBOL(__list_add); +EXPORT_SYMBOL(__list_add_valid); -void __list_del_entry(struct list_head *entry) +bool __list_del_entry_valid(struct list_head *entry) { struct list_head *prev, *next; prev = entry->prev; next = entry->next; - if (WARN(next == LIST_POISON1, + CHECK_DATA_CORRUPTION(next == LIST_POISON1, "list_del corruption, %p->next is LIST_POISON1 (%p)\n", - entry, LIST_POISON1) || - WARN(prev == LIST_POISON2, + entry, LIST_POISON1); + CHECK_DATA_CORRUPTION(prev == LIST_POISON2, "list_del corruption, %p->prev is LIST_POISON2 (%p)\n", - entry, LIST_POISON2) || - WARN(prev->next != entry, - "list_del corruption. prev->next should be %p, " - "but was %p\n", entry, prev->next) || - WARN(next->prev != entry, - "list_del corruption. next->prev should be %p, " - "but was %p\n", entry, next->prev)) - return; - - __list_del(prev, next); -} -EXPORT_SYMBOL(__list_del_entry); + entry, LIST_POISON2); + CHECK_DATA_CORRUPTION(prev->next != entry, + "list_del corruption. prev->next should be %p, but was %p\n", + entry, prev->next); + CHECK_DATA_CORRUPTION(next->prev != entry, + "list_del corruption. next->prev should be %p, but was %p\n", + entry, next->prev); + return true; -/** - * 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) -{ - __list_del_entry(entry); - entry->next = LIST_POISON1; - entry->prev = LIST_POISON2; -} -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); +EXPORT_SYMBOL(__list_del_entry_valid); |