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Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

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Pull RCU updates from Paul E. McKenney:

 - Documentation updates, yet again just simple changes.

 - Miscellaneous fixes, including a change to call_rcu()'s
   rcu_head alignment check.

 - Security-motivated list consistency checks, which are
   disabled by default behind DEBUG_LIST.

 - Torture-test updates.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar
2016-11-23 10:04:28 +01:00
parent 23400ac997 6190aaafd0
commit af91a81131
17 changed files with 222 additions and 108 deletions
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15
lib/Kconfig.debug
View File

@@ -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"

101
lib/list_debug.c
View File

@@ -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);
}
EXPORT_SYMBOL(__list_add);
CHECK_DATA_CORRUPTION(new == prev || new == next,
"list_add double add: new=%p, prev=%p, next=%p.\n",
new, prev, next);
void __list_del_entry(struct list_head *entry)
return true;
}
EXPORT_SYMBOL(__list_add_valid);
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;
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(prev, next);
}
EXPORT_SYMBOL(__list_del_entry);
/**
* 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);