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Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

Browse source 
* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (33 commits)
  lockdep: fix deadlock in lockdep_trace_alloc
  lockdep: annotate reclaim context (__GFP_NOFS), fix SLOB
  lockdep: annotate reclaim context (__GFP_NOFS), fix
  lockdep: build fix for !PROVE_LOCKING
  lockstat: warn about disabled lock debugging
  lockdep: use stringify.h
  lockdep: simplify check_prev_add_irq()
  lockdep: get_user_chars() redo
  lockdep: simplify get_user_chars()
  lockdep: add comments to mark_lock_irq()
  lockdep: remove macro usage from mark_held_locks()
  lockdep: fully reduce mark_lock_irq()
  lockdep: merge the !_READ mark_lock_irq() helpers
  lockdep: merge the _READ mark_lock_irq() helpers
  lockdep: simplify mark_lock_irq() helpers #3
  lockdep: further simplify mark_lock_irq() helpers
  lockdep: simplify the mark_lock_irq() helpers
  lockdep: split up mark_lock_irq()
  lockdep: generate usage strings
  lockdep: generate the state bit definitions
  ...
This commit is contained in:
Linus Torvalds 2009-03-30 17:17:35 -07:00
commit c4e1aa67ed
21 changed files with 731 additions and 380 deletions
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30
Documentation/lockdep-design.txt
View file

@ -27,33 +27,37 @@ lock-class.
State
-----
The validator tracks lock-class usage history into 5 separate state bits:
The validator tracks lock-class usage history into 4n + 1 separate state bits:
- 'ever held in hardirq context' [ == hardirq-safe ]
- 'ever held in softirq context' [ == softirq-safe ]
- 'ever held with hardirqs enabled' [ == hardirq-unsafe ]
- 'ever held with softirqs and hardirqs enabled' [ == softirq-unsafe ]
- 'ever held in STATE context'
- 'ever head as readlock in STATE context'
- 'ever head with STATE enabled'
- 'ever head as readlock with STATE enabled'
Where STATE can be either one of (kernel/lockdep_states.h)
- hardirq
- softirq
- reclaim_fs
- 'ever used' [ == !unused ]
When locking rules are violated, these 4 state bits are presented in the
locking error messages, inside curlies. A contrived example:
When locking rules are violated, these state bits are presented in the
locking error messages, inside curlies. A contrived example:
modprobe/2287 is trying to acquire lock:
(&sio_locks[i].lock){--..}, at: [<c02867fd>] mutex_lock+0x21/0x24
(&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24
but task is already holding lock:
(&sio_locks[i].lock){--..}, at: [<c02867fd>] mutex_lock+0x21/0x24
(&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24
The bit position indicates hardirq, softirq, hardirq-read,
softirq-read respectively, and the character displayed in each
indicates:
The bit position indicates STATE, STATE-read, for each of the states listed
above, and the character displayed in each indicates:
'.' acquired while irqs disabled
'+' acquired in irq context
'-' acquired with irqs enabled
'?' read acquired in irq context with irqs enabled.
'?' acquired in irq context with irqs enabled.
Unused mutexes cannot be part of the cause of an error.

50
include/linux/lockdep.h
View file

@ -20,43 +20,10 @@ struct lockdep_map;
#include <linux/stacktrace.h>
/*
* Lock-class usage-state bits:
* We'd rather not expose kernel/lockdep_states.h this wide, but we do need
* the total number of states... :-(
*/
enum lock_usage_bit
{
LOCK_USED = 0,
LOCK_USED_IN_HARDIRQ,
LOCK_USED_IN_SOFTIRQ,
LOCK_ENABLED_SOFTIRQS,
LOCK_ENABLED_HARDIRQS,
LOCK_USED_IN_HARDIRQ_READ,
LOCK_USED_IN_SOFTIRQ_READ,
LOCK_ENABLED_SOFTIRQS_READ,
LOCK_ENABLED_HARDIRQS_READ,
LOCK_USAGE_STATES
};
/*
* Usage-state bitmasks:
*/
#define LOCKF_USED (1 << LOCK_USED)
#define LOCKF_USED_IN_HARDIRQ (1 << LOCK_USED_IN_HARDIRQ)
#define LOCKF_USED_IN_SOFTIRQ (1 << LOCK_USED_IN_SOFTIRQ)
#define LOCKF_ENABLED_HARDIRQS (1 << LOCK_ENABLED_HARDIRQS)
#define LOCKF_ENABLED_SOFTIRQS (1 << LOCK_ENABLED_SOFTIRQS)
#define LOCKF_ENABLED_IRQS (LOCKF_ENABLED_HARDIRQS | LOCKF_ENABLED_SOFTIRQS)
#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
#define LOCKF_USED_IN_HARDIRQ_READ (1 << LOCK_USED_IN_HARDIRQ_READ)
#define LOCKF_USED_IN_SOFTIRQ_READ (1 << LOCK_USED_IN_SOFTIRQ_READ)
#define LOCKF_ENABLED_HARDIRQS_READ (1 << LOCK_ENABLED_HARDIRQS_READ)
#define LOCKF_ENABLED_SOFTIRQS_READ (1 << LOCK_ENABLED_SOFTIRQS_READ)
#define LOCKF_ENABLED_IRQS_READ \
(LOCKF_ENABLED_HARDIRQS_READ | LOCKF_ENABLED_SOFTIRQS_READ)
#define LOCKF_USED_IN_IRQ_READ \
(LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
#define XXX_LOCK_USAGE_STATES (1+3*4)
#define MAX_LOCKDEP_SUBCLASSES 8UL
@ -97,7 +64,7 @@ struct lock_class {
* IRQ/softirq usage tracking bits:
*/
unsigned long usage_mask;
struct stack_trace usage_traces[LOCK_USAGE_STATES];
struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES];
/*
* These fields represent a directed graph of lock dependencies,
@ -324,7 +291,11 @@ static inline void lock_set_subclass(struct lockdep_map *lock,
lock_set_class(lock, lock->name, lock->key, subclass, ip);
}
# define INIT_LOCKDEP .lockdep_recursion = 0,
extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
extern void lockdep_clear_current_reclaim_state(void);
extern void lockdep_trace_alloc(gfp_t mask);
# define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,
#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
@ -342,6 +313,9 @@ static inline void lockdep_on(void)
# define lock_release(l, n, i) do { } while (0)
# define lock_set_class(l, n, k, s, i) do { } while (0)
# define lock_set_subclass(l, s, i) do { } while (0)
# define lockdep_set_current_reclaim_state(g) do { } while (0)
# define lockdep_clear_current_reclaim_state() do { } while (0)
# define lockdep_trace_alloc(g) do { } while (0)
# define lockdep_init() do { } while (0)
# define lockdep_info() do { } while (0)
# define lockdep_init_map(lock, name, key, sub) \

5
include/linux/mutex.h
View file

@ -50,8 +50,10 @@ struct mutex {
atomic_t count;
spinlock_t wait_lock;
struct list_head wait_list;
#ifdef CONFIG_DEBUG_MUTEXES
#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP)
struct thread_info *owner;
#endif
#ifdef CONFIG_DEBUG_MUTEXES
const char *name;
void *magic;
#endif
@ -68,7 +70,6 @@ struct mutex_waiter {
struct list_head list;
struct task_struct *task;
#ifdef CONFIG_DEBUG_MUTEXES
struct mutex *lock;
void *magic;
#endif
};

3
include/linux/sched.h
View file

@ -331,7 +331,9 @@ extern signed long schedule_timeout(signed long timeout);
extern signed long schedule_timeout_interruptible(signed long timeout);
extern signed long schedule_timeout_killable(signed long timeout);
extern signed long schedule_timeout_uninterruptible(signed long timeout);
asmlinkage void __schedule(void);
asmlinkage void schedule(void);
extern int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner);
struct nsproxy;
struct user_namespace;
@ -1334,6 +1336,7 @@ struct task_struct {
int lockdep_depth;
unsigned int lockdep_recursion;
struct held_lock held_locks[MAX_LOCK_DEPTH];
gfp_t lockdep_reclaim_gfp;
#endif
/* journalling filesystem info */

93
include/linux/timer.h
View file

@ -5,6 +5,7 @@
#include <linux/ktime.h>
#include <linux/stddef.h>
#include <linux/debugobjects.h>
#include <linux/stringify.h>
struct tvec_base;
@ -21,52 +22,126 @@ struct timer_list {
char start_comm[16];
int start_pid;
#endif
#ifdef CONFIG_LOCKDEP
struct lockdep_map lockdep_map;
#endif
};
extern struct tvec_base boot_tvec_bases;
#ifdef CONFIG_LOCKDEP
/*
* NB: because we have to copy the lockdep_map, setting the lockdep_map key
* (second argument) here is required, otherwise it could be initialised to
* the copy of the lockdep_map later! We use the pointer to and the string
* "<file>:<line>" as the key resp. the name of the lockdep_map.
*/
#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
#else
#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
#endif
#define TIMER_INITIALIZER(_function, _expires, _data) { \
.entry = { .prev = TIMER_ENTRY_STATIC }, \
.function = (_function), \
.expires = (_expires), \
.data = (_data), \
.base = &boot_tvec_bases, \
__TIMER_LOCKDEP_MAP_INITIALIZER( \
__FILE__ ":" __stringify(__LINE__)) \
}
#define DEFINE_TIMER(_name, _function, _expires, _data) \
struct timer_list _name = \
TIMER_INITIALIZER(_function, _expires, _data)
void init_timer(struct timer_list *timer);
void init_timer_deferrable(struct timer_list *timer);
void init_timer_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
void init_timer_deferrable_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
#ifdef CONFIG_LOCKDEP
#define init_timer(timer) \
do { \
static struct lock_class_key __key; \
init_timer_key((timer), #timer, &__key); \
} while (0)
#define init_timer_deferrable(timer) \
do { \
static struct lock_class_key __key; \
init_timer_deferrable_key((timer), #timer, &__key); \
} while (0)
#define init_timer_on_stack(timer) \
do { \
static struct lock_class_key __key; \
init_timer_on_stack_key((timer), #timer, &__key); \
} while (0)
#define setup_timer(timer, fn, data) \
do { \
static struct lock_class_key __key; \
setup_timer_key((timer), #timer, &__key, (fn), (data));\
} while (0)
#define setup_timer_on_stack(timer, fn, data) \
do { \
static struct lock_class_key __key; \
setup_timer_on_stack_key((timer), #timer, &__key, \
(fn), (data)); \
} while (0)
#else
#define init_timer(timer)\
init_timer_key((timer), NULL, NULL)
#define init_timer_deferrable(timer)\
init_timer_deferrable_key((timer), NULL, NULL)
#define init_timer_on_stack(timer)\
init_timer_on_stack_key((timer), NULL, NULL)
#define setup_timer(timer, fn, data)\
setup_timer_key((timer), NULL, NULL, (fn), (data))
#define setup_timer_on_stack(timer, fn, data)\
setup_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
#endif
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
extern void init_timer_on_stack(struct timer_list *timer);
extern void init_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
extern void destroy_timer_on_stack(struct timer_list *timer);
#else
static inline void destroy_timer_on_stack(struct timer_list *timer) { }
static inline void init_timer_on_stack(struct timer_list *timer)
static inline void init_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
init_timer(timer);
init_timer_key(timer, name, key);
}
#endif
static inline void setup_timer(struct timer_list * timer,
static inline void setup_timer_key(struct timer_list * timer,
const char *name,
struct lock_class_key *key,
void (*function)(unsigned long),
unsigned long data)
{
timer->function = function;
timer->data = data;
init_timer(timer);
init_timer_key(timer, name, key);
}
static inline void setup_timer_on_stack(struct timer_list *timer,
static inline void setup_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key,
void (*function)(unsigned long),
unsigned long data)
{
timer->function = function;
timer->data = data;
init_timer_on_stack(timer);
init_timer_on_stack_key(timer, name, key);
}
/**

530
kernel/lockdep.c
View file

@ -41,6 +41,7 @@
#include <linux/utsname.h>
#include <linux/hash.h>
#include <linux/ftrace.h>
#include <linux/stringify.h>
#include <asm/sections.h>
@ -310,12 +311,14 @@ EXPORT_SYMBOL(lockdep_on);
#if VERBOSE
# define HARDIRQ_VERBOSE 1
# define SOFTIRQ_VERBOSE 1
# define RECLAIM_VERBOSE 1
#else
# define HARDIRQ_VERBOSE 0
# define SOFTIRQ_VERBOSE 0
# define RECLAIM_VERBOSE 0
#endif
#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
/*
* Quick filtering for interesting events:
*/
@ -443,17 +446,18 @@ atomic_t nr_find_usage_backwards_recursions;
* Locking printouts:
*/
#define __USAGE(__STATE) \
[LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
[LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
[LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
[LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
static const char *usage_str[] =
{
[LOCK_USED] = "initial-use ",
[LOCK_USED_IN_HARDIRQ] = "in-hardirq-W",
[LOCK_USED_IN_SOFTIRQ] = "in-softirq-W",
[LOCK_ENABLED_SOFTIRQS] = "softirq-on-W",
[LOCK_ENABLED_HARDIRQS] = "hardirq-on-W",
[LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R",
[LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R",
[LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R",
[LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R",
#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
#include "lockdep_states.h"
#undef LOCKDEP_STATE
[LOCK_USED] = "INITIAL USE",
};
const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
@ -461,46 +465,45 @@ const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
}
void
get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4)
static inline unsigned long lock_flag(enum lock_usage_bit bit)
{
*c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.';
return 1UL << bit;
}
if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
*c1 = '+';
else
if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
*c1 = '-';
static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
{
char c = '.';
if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
*c2 = '+';
else
if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
*c2 = '-';
if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
*c3 = '-';
if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) {
*c3 = '+';
if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
*c3 = '?';
if (class->usage_mask & lock_flag(bit + 2))
c = '+';
if (class->usage_mask & lock_flag(bit)) {
c = '-';
if (class->usage_mask & lock_flag(bit + 2))
c = '?';
}
if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
*c4 = '-';
if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) {
*c4 = '+';
if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
*c4 = '?';
}
return c;
}
void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
{
int i = 0;
#define LOCKDEP_STATE(__STATE) \
usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
#include "lockdep_states.h"
#undef LOCKDEP_STATE
usage[i] = '\0';
}
static void print_lock_name(struct lock_class *class)
{
char str[KSYM_NAME_LEN], c1, c2, c3, c4;
char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS];
const char *name;
get_usage_chars(class, &c1, &c2, &c3, &c4);
get_usage_chars(class, usage);
name = class->name;
if (!name) {
@ -513,7 +516,7 @@ static void print_lock_name(struct lock_class *class)
if (class->subclass)
printk("/%d", class->subclass);
}
printk("){%c%c%c%c}", c1, c2, c3, c4);
printk("){%s}", usage);
}
static void print_lockdep_cache(struct lockdep_map *lock)
@ -1263,9 +1266,49 @@ check_usage(struct task_struct *curr, struct held_lock *prev,
bit_backwards, bit_forwards, irqclass);
}
static int
check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
static const char *state_names[] = {
#define LOCKDEP_STATE(__STATE) \
__stringify(__STATE),
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};
static const char *state_rnames[] = {
#define LOCKDEP_STATE(__STATE) \
__stringify(__STATE)"-READ",
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};
static inline const char *state_name(enum lock_usage_bit bit)
{
return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
}
static int exclusive_bit(int new_bit)
{
/*
* USED_IN
* USED_IN_READ
* ENABLED
* ENABLED_READ
*
* bit 0 - write/read
* bit 1 - used_in/enabled
* bit 2+ state
*/
int state = new_bit & ~3;
int dir = new_bit & 2;
/*
* keep state, bit flip the direction and strip read.
*/
return state | (dir ^ 2);
}
static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next, enum lock_usage_bit bit)
{
/*
* Prove that the new dependency does not connect a hardirq-safe
@ -1273,38 +1316,34 @@ check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
* the backwards-subgraph starting at <prev>, and the
* forwards-subgraph starting at <next>:
*/
if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
LOCK_ENABLED_HARDIRQS, "hard"))
if (!check_usage(curr, prev, next, bit,
exclusive_bit(bit), state_name(bit)))
return 0;
bit++; /* _READ */
/*
* Prove that the new dependency does not connect a hardirq-safe-read
* lock with a hardirq-unsafe lock - to achieve this we search
* the backwards-subgraph starting at <prev>, and the
* forwards-subgraph starting at <next>:
*/
if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
LOCK_ENABLED_HARDIRQS, "hard-read"))
if (!check_usage(curr, prev, next, bit,
exclusive_bit(bit), state_name(bit)))
return 0;
/*
* Prove that the new dependency does not connect a softirq-safe
* lock with a softirq-unsafe lock - to achieve this we search
* the backwards-subgraph starting at <prev>, and the
* forwards-subgraph starting at <next>:
*/
if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
LOCK_ENABLED_SOFTIRQS, "soft"))
return 0;
/*
* Prove that the new dependency does not connect a softirq-safe-read
* lock with a softirq-unsafe lock - to achieve this we search
* the backwards-subgraph starting at <prev>, and the
* forwards-subgraph starting at <next>:
*/
if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
LOCK_ENABLED_SOFTIRQS, "soft"))
return 1;
}
static int
check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
{
#define LOCKDEP_STATE(__STATE) \
if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
return 0;
#include "lockdep_states.h"
#undef LOCKDEP_STATE
return 1;
}
@ -1933,7 +1972,7 @@ void print_irqtrace_events(struct task_struct *curr)
print_ip_sym(curr->softirq_disable_ip);
}
static int hardirq_verbose(struct lock_class *class)
static int HARDIRQ_verbose(struct lock_class *class)
{
#if HARDIRQ_VERBOSE
return class_filter(class);
@ -1941,7 +1980,7 @@ static int hardirq_verbose(struct lock_class *class)
return 0;
}
static int softirq_verbose(struct lock_class *class)
static int SOFTIRQ_verbose(struct lock_class *class)
{
#if SOFTIRQ_VERBOSE
return class_filter(class);
@ -1949,185 +1988,94 @@ static int softirq_verbose(struct lock_class *class)
return 0;
}
static int RECLAIM_FS_verbose(struct lock_class *class)
{
#if RECLAIM_VERBOSE
return class_filter(class);
#endif
return 0;
}
#define STRICT_READ_CHECKS 1
static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit)
{
int ret = 1;
static int (*state_verbose_f[])(struct lock_class *class) = {
#define LOCKDEP_STATE(__STATE) \
__STATE##_verbose,
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};
switch(new_bit) {
case LOCK_USED_IN_HARDIRQ:
if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
static inline int state_verbose(enum lock_usage_bit bit,
struct lock_class *class)
{
return state_verbose_f[bit >> 2](class);
}
typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
enum lock_usage_bit bit, const char *name);
static int
mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
{
int excl_bit = exclusive_bit(new_bit);
int read = new_bit & 1;
int dir = new_bit & 2;
/*
* mark USED_IN has to look forwards -- to ensure no dependency
* has ENABLED state, which would allow recursion deadlocks.
*
* mark ENABLED has to look backwards -- to ensure no dependee
* has USED_IN state, which, again, would allow recursion deadlocks.
*/
check_usage_f usage = dir ?
check_usage_backwards : check_usage_forwards;
/*
* Validate that this particular lock does not have conflicting
* usage states.
*/
if (!valid_state(curr, this, new_bit, excl_bit))
return 0;
/*
* Validate that the lock dependencies don't have conflicting usage
* states.
*/
if ((!read || !dir || STRICT_READ_CHECKS) &&
!usage(curr, this, excl_bit, state_name(new_bit)))
return 0;
/*
* Check for read in write conflicts
*/
if (!read) {
if (!valid_state(curr, this, new_bit, excl_bit + 1))
return 0;
if (!valid_state(curr, this, new_bit,
LOCK_ENABLED_HARDIRQS_READ))
if (STRICT_READ_CHECKS &&
!usage(curr, this, excl_bit + 1,
state_name(new_bit + 1)))
return 0;
/*
* just marked it hardirq-safe, check that this lock
* took no hardirq-unsafe lock in the past:
*/
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_HARDIRQS, "hard"))
return 0;
#if STRICT_READ_CHECKS
/*
* just marked it hardirq-safe, check that this lock
* took no hardirq-unsafe-read lock in the past:
*/
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_HARDIRQS_READ, "hard-read"))
return 0;
#endif
if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_USED_IN_SOFTIRQ:
if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
return 0;
if (!valid_state(curr, this, new_bit,
LOCK_ENABLED_SOFTIRQS_READ))
return 0;
/*
* just marked it softirq-safe, check that this lock
* took no softirq-unsafe lock in the past:
*/
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_SOFTIRQS, "soft"))
return 0;
#if STRICT_READ_CHECKS
/*
* just marked it softirq-safe, check that this lock
* took no softirq-unsafe-read lock in the past:
*/
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_SOFTIRQS_READ, "soft-read"))
return 0;
#endif
if (softirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_USED_IN_HARDIRQ_READ:
if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
return 0;
/*
* just marked it hardirq-read-safe, check that this lock
* took no hardirq-unsafe lock in the past:
*/
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_HARDIRQS, "hard"))
return 0;
if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_USED_IN_SOFTIRQ_READ:
if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
return 0;
/*
* just marked it softirq-read-safe, check that this lock
* took no softirq-unsafe lock in the past:
*/
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_SOFTIRQS, "soft"))
return 0;
if (softirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_HARDIRQS:
if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
return 0;
if (!valid_state(curr, this, new_bit,
LOCK_USED_IN_HARDIRQ_READ))
return 0;
/*
* just marked it hardirq-unsafe, check that no hardirq-safe
* lock in the system ever took it in the past:
*/
if (!check_usage_backwards(curr, this,
LOCK_USED_IN_HARDIRQ, "hard"))
return 0;
#if STRICT_READ_CHECKS
/*
* just marked it hardirq-unsafe, check that no
* hardirq-safe-read lock in the system ever took
* it in the past:
*/
if (!check_usage_backwards(curr, this,
LOCK_USED_IN_HARDIRQ_READ, "hard-read"))
return 0;
#endif
if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_SOFTIRQS:
if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
return 0;
if (!valid_state(curr, this, new_bit,
LOCK_USED_IN_SOFTIRQ_READ))
return 0;
/*
* just marked it softirq-unsafe, check that no softirq-safe
* lock in the system ever took it in the past:
*/
if (!check_usage_backwards(curr, this,
LOCK_USED_IN_SOFTIRQ, "soft"))
return 0;
#if STRICT_READ_CHECKS
/*
* just marked it softirq-unsafe, check that no
* softirq-safe-read lock in the system ever took
* it in the past:
*/
if (!check_usage_backwards(curr, this,
LOCK_USED_IN_SOFTIRQ_READ, "soft-read"))
return 0;
#endif
if (softirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_HARDIRQS_READ:
if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
return 0;
#if STRICT_READ_CHECKS
/*
* just marked it hardirq-read-unsafe, check that no
* hardirq-safe lock in the system ever took it in the past:
*/
if (!check_usage_backwards(curr, this,
LOCK_USED_IN_HARDIRQ, "hard"))
return 0;
#endif
if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_SOFTIRQS_READ:
if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
return 0;
#if STRICT_READ_CHECKS
/*
* just marked it softirq-read-unsafe, check that no
* softirq-safe lock in the system ever took it in the past:
*/
if (!check_usage_backwards(curr, this,
LOCK_USED_IN_SOFTIRQ, "soft"))
return 0;
#endif
if (softirq_verbose(hlock_class(this)))
ret = 2;
break;
default:
WARN_ON(1);
break;
}
return ret;
if (state_verbose(new_bit, hlock_class(this)))
return 2;
return 1;
}
enum mark_type {
#define LOCKDEP_STATE(__STATE) __STATE,
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};
/*
* Mark all held locks with a usage bit:
*/
static int
mark_held_locks(struct task_struct *curr, int hardirq)
mark_held_locks(struct task_struct *curr, enum mark_type mark)
{
enum lock_usage_bit usage_bit;
struct held_lock *hlock;
@ -2136,17 +2084,12 @@ mark_held_locks(struct task_struct *curr, int hardirq)
for (i = 0; i < curr->lockdep_depth; i++) {
hlock = curr->held_locks + i;
if (hardirq) {
if (hlock->read)
usage_bit = LOCK_ENABLED_HARDIRQS_READ;
else
usage_bit = LOCK_ENABLED_HARDIRQS;
} else {
if (hlock->read)
usage_bit = LOCK_ENABLED_SOFTIRQS_READ;
else
usage_bit = LOCK_ENABLED_SOFTIRQS;
}
usage_bit = 2 + (mark << 2); /* ENABLED */
if (hlock->read)
usage_bit += 1; /* READ */
BUG_ON(usage_bit >= LOCK_USAGE_STATES);
if (!mark_lock(curr, hlock, usage_bit))
return 0;
}
@ -2200,7 +2143,7 @@ void trace_hardirqs_on_caller(unsigned long ip)
* We are going to turn hardirqs on, so set the
* usage bit for all held locks:
*/
if (!mark_held_locks(curr, 1))
if (!mark_held_locks(curr, HARDIRQ))
return;
/*
* If we have softirqs enabled, then set the usage
@ -2208,7 +2151,7 @@ void trace_hardirqs_on_caller(unsigned long ip)
* this bit from being set before)
*/
if (curr->softirqs_enabled)
if (!mark_held_locks(curr, 0))
if (!mark_held_locks(curr, SOFTIRQ))
return;
curr->hardirq_enable_ip = ip;
@ -2288,7 +2231,7 @@ void trace_softirqs_on(unsigned long ip)
* enabled too:
*/
if (curr->hardirqs_enabled)
mark_held_locks(curr, 0);
mark_held_locks(curr, SOFTIRQ);
}
/*
@ -2317,6 +2260,48 @@ void trace_softirqs_off(unsigned long ip)
debug_atomic_inc(&redundant_softirqs_off);
}
static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
{
struct task_struct *curr = current;
if (unlikely(!debug_locks))
return;
/* no reclaim without waiting on it */
if (!(gfp_mask & __GFP_WAIT))
return;
/* this guy won't enter reclaim */
if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
return;
/* We're only interested __GFP_FS allocations for now */
if (!(gfp_mask & __GFP_FS))
return;
if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
return;
mark_held_locks(curr, RECLAIM_FS);
}
static void check_flags(unsigned long flags);
void lockdep_trace_alloc(gfp_t gfp_mask)
{
unsigned long flags;
if (unlikely(current->lockdep_recursion))
return;
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion = 1;
__lockdep_trace_alloc(gfp_mask, flags);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
{
/*
@ -2345,19 +2330,35 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
if (!hlock->hardirqs_off) {
if (hlock->read) {
if (!mark_lock(curr, hlock,
LOCK_ENABLED_HARDIRQS_READ))
LOCK_ENABLED_HARDIRQ_READ))
return 0;
if (curr->softirqs_enabled)
if (!mark_lock(curr, hlock,
LOCK_ENABLED_SOFTIRQS_READ))
LOCK_ENABLED_SOFTIRQ_READ))
return 0;
} else {
if (!mark_lock(curr, hlock,
LOCK_ENABLED_HARDIRQS))
LOCK_ENABLED_HARDIRQ))
return 0;
if (curr->softirqs_enabled)
if (!mark_lock(curr, hlock,
LOCK_ENABLED_SOFTIRQS))
LOCK_ENABLED_SOFTIRQ))
return 0;
}
}
/*
* We reuse the irq context infrastructure more broadly as a general
* context checking code. This tests GFP_FS recursion (a lock taken
* during reclaim for a GFP_FS allocation is held over a GFP_FS
* allocation).
*/
if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
if (hlock->read) {
if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
return 0;
} else {
if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
return 0;
}
}
@ -2412,6 +2413,10 @@ static inline int separate_irq_context(struct task_struct *curr,
return 0;
}
void lockdep_trace_alloc(gfp_t gfp_mask)
{
}
#endif
/*
@ -2445,14 +2450,13 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
return 0;
switch (new_bit) {
case LOCK_USED_IN_HARDIRQ:
case LOCK_USED_IN_SOFTIRQ:
case LOCK_USED_IN_HARDIRQ_READ:
case LOCK_USED_IN_SOFTIRQ_READ:
case LOCK_ENABLED_HARDIRQS:
case LOCK_ENABLED_SOFTIRQS:
case LOCK_ENABLED_HARDIRQS_READ:
case LOCK_ENABLED_SOFTIRQS_READ:
#define LOCKDEP_STATE(__STATE) \
case LOCK_USED_IN_##__STATE: \
case LOCK_USED_IN_##__STATE##_READ: \
case LOCK_ENABLED_##__STATE: \
case LOCK_ENABLED_##__STATE##_READ:
#include "lockdep_states.h"
#undef LOCKDEP_STATE
ret = mark_lock_irq(curr, this, new_bit);
if (!ret)
return 0;
@ -2966,6 +2970,16 @@ void lock_release(struct lockdep_map *lock, int nested,
}
EXPORT_SYMBOL_GPL(lock_release);
void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
{
current->lockdep_reclaim_gfp = gfp_mask;
}
void lockdep_clear_current_reclaim_state(void)
{
current->lockdep_reclaim_gfp = 0;
}
#ifdef CONFIG_LOCK_STAT
static int
print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,

45
kernel/lockdep_internals.h
View file

@ -6,6 +6,45 @@
* lockdep subsystem internal functions and variables.
*/
/*
* Lock-class usage-state bits:
*/
enum lock_usage_bit {
#define LOCKDEP_STATE(__STATE) \
LOCK_USED_IN_##__STATE, \
LOCK_USED_IN_##__STATE##_READ, \
LOCK_ENABLED_##__STATE, \
LOCK_ENABLED_##__STATE##_READ,
#include "lockdep_states.h"
#undef LOCKDEP_STATE
LOCK_USED,
LOCK_USAGE_STATES
};
/*
* Usage-state bitmasks:
*/
#define __LOCKF(__STATE) LOCKF_##__STATE = (1 << LOCK_##__STATE),
enum {
#define LOCKDEP_STATE(__STATE) \
__LOCKF(USED_IN_##__STATE) \
__LOCKF(USED_IN_##__STATE##_READ) \
__LOCKF(ENABLED_##__STATE) \
__LOCKF(ENABLED_##__STATE##_READ)
#include "lockdep_states.h"
#undef LOCKDEP_STATE
__LOCKF(USED)
};
#define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ)
#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
#define LOCKF_ENABLED_IRQ_READ \
(LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ)
#define LOCKF_USED_IN_IRQ_READ \
(LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
/*
* MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
* we track.
@ -31,8 +70,10 @@
extern struct list_head all_lock_classes;
extern struct lock_chain lock_chains[];
extern void
get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
#define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)
extern void get_usage_chars(struct lock_class *class,
char usage[LOCK_USAGE_CHARS]);
extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);

22
kernel/lockdep_proc.c
View file

@ -84,7 +84,7 @@ static int l_show(struct seq_file *m, void *v)
{
struct lock_class *class = v;
struct lock_list *entry;
char c1, c2, c3, c4;
char usage[LOCK_USAGE_CHARS];
if (v == SEQ_START_TOKEN) {
seq_printf(m, "all lock classes:\n");
@ -100,8 +100,8 @@ static int l_show(struct seq_file *m, void *v)
seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
#endif
get_usage_chars(class, &c1, &c2, &c3, &c4);
seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
get_usage_chars(class, usage);
seq_printf(m, " %s", usage);
seq_printf(m, ": ");
print_name(m, class);
@ -300,27 +300,27 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
nr_uncategorized++;
if (class->usage_mask & LOCKF_USED_IN_IRQ)
nr_irq_safe++;
if (class->usage_mask & LOCKF_ENABLED_IRQS)
if (class->usage_mask & LOCKF_ENABLED_IRQ)
nr_irq_unsafe++;
if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
nr_softirq_safe++;
if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
nr_softirq_unsafe++;
if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
nr_hardirq_safe++;
if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
nr_hardirq_unsafe++;
if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
nr_irq_read_safe++;
if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
nr_irq_read_unsafe++;
if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
nr_softirq_read_safe++;
if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
nr_softirq_read_unsafe++;
if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
nr_hardirq_read_safe++;
if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
nr_hardirq_read_unsafe++;
#ifdef CONFIG_PROVE_LOCKING
@ -601,6 +601,10 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
static void seq_header(struct seq_file *m)
{
seq_printf(m, "lock_stat version 0.3\n");
if (unlikely(!debug_locks))
seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
"%14s %14s\n",

9
kernel/lockdep_states.h Normal file
View file

@ -0,0 +1,9 @@
/*
* Lockdep states,
*
* please update XXX_LOCK_USAGE_STATES in include/linux/lockdep.h whenever
* you add one, or come up with a nice dynamic solution.
*/
LOCKDEP_STATE(HARDIRQ)
LOCKDEP_STATE(SOFTIRQ)
LOCKDEP_STATE(RECLAIM_FS)

9
kernel/mutex-debug.c
View file

@ -26,11 +26,6 @@
/*
* Must be called with lock->wait_lock held.
*/
void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
{
lock->owner = new_owner;
}
void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
{
memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
@ -59,7 +54,6 @@ void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
/* Mark the current thread as blocked on the lock: */
ti->task->blocked_on = waiter;
waiter->lock = lock;
}
void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
@ -82,7 +76,7 @@ void debug_mutex_unlock(struct mutex *lock)
DEBUG_LOCKS_WARN_ON(lock->magic != lock);
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
mutex_clear_owner(lock);
}
void debug_mutex_init(struct mutex *lock, const char *name,
@ -95,7 +89,6 @@ void debug_mutex_init(struct mutex *lock, const char *name,
debug_check_no_locks_freed((void *)lock, sizeof(*lock));
lockdep_init_map(&lock->dep_map, name, key, 0);
#endif
lock->owner = NULL;
lock->magic = lock;
}

18
kernel/mutex-debug.h
View file

@ -13,14 +13,6 @@
/*
* This must be called with lock->wait_lock held.
*/
extern void
debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner);
static inline void debug_mutex_clear_owner(struct mutex *lock)
{
lock->owner = NULL;
}
extern void debug_mutex_lock_common(struct mutex *lock,
struct mutex_waiter *waiter);
extern void debug_mutex_wake_waiter(struct mutex *lock,
@ -35,6 +27,16 @@ extern void debug_mutex_unlock(struct mutex *lock);
extern void debug_mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key);
static inline void mutex_set_owner(struct mutex *lock)
{
lock->owner = current_thread_info();
}
static inline void mutex_clear_owner(struct mutex *lock)
{
lock->owner = NULL;
}
#define spin_lock_mutex(lock, flags) \
do { \
struct mutex *l = container_of(lock, struct mutex, wait_lock); \

121
kernel/mutex.c
View file

@ -10,6 +10,11 @@
* Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
* David Howells for suggestions and improvements.
*
* - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
* from the -rt tree, where it was originally implemented for rtmutexes
* by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
* and Sven Dietrich.
*
* Also see Documentation/mutex-design.txt.
*/
#include <linux/mutex.h>
@ -46,6 +51,7 @@ __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
atomic_set(&lock->count, 1);
spin_lock_init(&lock->wait_lock);
INIT_LIST_HEAD(&lock->wait_list);
mutex_clear_owner(lock);
debug_mutex_init(lock, name, key);
}
@ -91,6 +97,7 @@ void inline __sched mutex_lock(struct mutex *lock)
* 'unlocked' into 'locked' state.
*/
__mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
mutex_set_owner(lock);
}
EXPORT_SYMBOL(mutex_lock);
@ -115,6 +122,14 @@ void __sched mutex_unlock(struct mutex *lock)
* The unlocking fastpath is the 0->1 transition from 'locked'
* into 'unlocked' state:
*/
#ifndef CONFIG_DEBUG_MUTEXES
/*
* When debugging is enabled we must not clear the owner before time,
* the slow path will always be taken, and that clears the owner field
* after verifying that it was indeed current.
*/
mutex_clear_owner(lock);
#endif
__mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
}
@ -129,21 +144,75 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
{
struct task_struct *task = current;
struct mutex_waiter waiter;
unsigned int old_val;
unsigned long flags;
preempt_disable();
mutex_acquire(&lock->dep_map, subclass, 0, ip);
#if defined(CONFIG_SMP) && !defined(CONFIG_DEBUG_MUTEXES)
/*
* Optimistic spinning.
*
* We try to spin for acquisition when we find that there are no
* pending waiters and the lock owner is currently running on a
* (different) CPU.
*
* The rationale is that if the lock owner is running, it is likely to
* release the lock soon.
*
* Since this needs the lock owner, and this mutex implementation
* doesn't track the owner atomically in the lock field, we need to
* track it non-atomically.
*
* We can't do this for DEBUG_MUTEXES because that relies on wait_lock
* to serialize everything.
*/
for (;;) {
struct thread_info *owner;
/*
* If there's an owner, wait for it to either
* release the lock or go to sleep.
*/
owner = ACCESS_ONCE(lock->owner);
if (owner && !mutex_spin_on_owner(lock, owner))
break;
if (atomic_cmpxchg(&lock->count, 1, 0) == 1) {
lock_acquired(&lock->dep_map, ip);
mutex_set_owner(lock);
preempt_enable();
return 0;
}
/*
* When there's no owner, we might have preempted between the
* owner acquiring the lock and setting the owner field. If
* we're an RT task that will live-lock because we won't let
* the owner complete.
*/
if (!owner && (need_resched() || rt_task(task)))
break;
/*
* The cpu_relax() call is a compiler barrier which forces
* everything in this loop to be re-loaded. We don't need
* memory barriers as we'll eventually observe the right
* values at the cost of a few extra spins.
*/
cpu_relax();
}
#endif
spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_lock_common(lock, &waiter);
mutex_acquire(&lock->dep_map, subclass, 0, ip);
debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
/* add waiting tasks to the end of the waitqueue (FIFO): */
list_add_tail(&waiter.list, &lock->wait_list);
waiter.task = task;
old_val = atomic_xchg(&lock->count, -1);
if (old_val == 1)
if (atomic_xchg(&lock->count, -1) == 1)
goto done;
lock_contended(&lock->dep_map, ip);
@ -158,8 +227,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* that when we release the lock, we properly wake up the
* other waiters:
*/
old_val = atomic_xchg(&lock->count, -1);
if (old_val == 1)
if (atomic_xchg(&lock->count, -1) == 1)
break;
/*
@ -173,21 +241,22 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
preempt_enable();
return -EINTR;
}
__set_task_state(task, state);
/* didnt get the lock, go to sleep: */
spin_unlock_mutex(&lock->wait_lock, flags);
schedule();
__schedule();
spin_lock_mutex(&lock->wait_lock, flags);
}
done:
lock_acquired(&lock->dep_map, ip);
/* got the lock - rejoice! */
mutex_remove_waiter(lock, &waiter, task_thread_info(task));
debug_mutex_set_owner(lock, task_thread_info(task));
mutex_remove_waiter(lock, &waiter, current_thread_info());
mutex_set_owner(lock);
/* set it to 0 if there are no waiters left: */
if (likely(list_empty(&lock->wait_list)))
@ -196,6 +265,7 @@ done:
spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
preempt_enable();
return 0;
}
@ -222,7 +292,8 @@ int __sched
mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass, _RET_IP_);
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
subclass, _RET_IP_);
}
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
@ -260,8 +331,6 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
wake_up_process(waiter->task);
}
debug_mutex_clear_owner(lock);
spin_unlock_mutex(&lock->wait_lock, flags);
}
@ -298,18 +367,30 @@ __mutex_lock_interruptible_slowpath(atomic_t *lock_count);
*/
int __sched mutex_lock_interruptible(struct mutex *lock)
{
int ret;
might_sleep();
return __mutex_fastpath_lock_retval
ret = __mutex_fastpath_lock_retval
(&lock->count, __mutex_lock_interruptible_slowpath);
if (!ret)
mutex_set_owner(lock);
return ret;
}
EXPORT_SYMBOL(mutex_lock_interruptible);
int __sched mutex_lock_killable(struct mutex *lock)
{
int ret;
might_sleep();
return __mutex_fastpath_lock_retval
ret = __mutex_fastpath_lock_retval
(&lock->count, __mutex_lock_killable_slowpath);
if (!ret)
mutex_set_owner(lock);
return ret;
}
EXPORT_SYMBOL(mutex_lock_killable);
@ -352,9 +433,10 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
prev = atomic_xchg(&lock->count, -1);
if (likely(prev == 1)) {
debug_mutex_set_owner(lock, current_thread_info());
mutex_set_owner(lock);
mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
}
/* Set it back to 0 if there are no waiters: */
if (likely(list_empty(&lock->wait_list)))
atomic_set(&lock->count, 0);
@ -380,8 +462,13 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
*/
int __sched mutex_trylock(struct mutex *lock)
{
return __mutex_fastpath_trylock(&lock->count,
__mutex_trylock_slowpath);
int ret;
ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
if (ret)
mutex_set_owner(lock);
return ret;
}
EXPORT_SYMBOL(mutex_trylock);

22
kernel/mutex.h
View file

@ -16,8 +16,26 @@
#define mutex_remove_waiter(lock, waiter, ti) \
__list_del((waiter)->list.prev, (waiter)->list.next)
#define debug_mutex_set_owner(lock, new_owner) do { } while (0)
#define debug_mutex_clear_owner(lock) do { } while (0)
#ifdef CONFIG_SMP
static inline void mutex_set_owner(struct mutex *lock)
{
lock->owner = current_thread_info();
}
static inline void mutex_clear_owner(struct mutex *lock)
{
lock->owner = NULL;
}
#else
static inline void mutex_set_owner(struct mutex *lock)
{
}
static inline void mutex_clear_owner(struct mutex *lock)
{
}
#endif
#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
#define debug_mutex_free_waiter(waiter) do { } while (0)
#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)

71
kernel/sched.c
View file

@ -4942,15 +4942,13 @@ pick_next_task(struct rq *rq)
/*
* schedule() is the main scheduler function.
*/
asmlinkage void __sched schedule(void)
asmlinkage void __sched __schedule(void)
{
struct task_struct *prev, *next;
unsigned long *switch_count;
struct rq *rq;
int cpu;
need_resched:
preempt_disable();
cpu = smp_processor_id();
rq = cpu_rq(cpu);
rcu_qsctr_inc(cpu);
@ -5007,13 +5005,80 @@ need_resched_nonpreemptible:
if (unlikely(reacquire_kernel_lock(current) < 0))
goto need_resched_nonpreemptible;
}
asmlinkage void __sched schedule(void)
{
need_resched:
preempt_disable();
__schedule();
preempt_enable_no_resched();
if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
goto need_resched;
}
EXPORT_SYMBOL(schedule);
#ifdef CONFIG_SMP
/*
* Look out! "owner" is an entirely speculative pointer
* access and not reliable.
*/
int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
{
unsigned int cpu;
struct rq *rq;
if (!sched_feat(OWNER_SPIN))
return 0;
#ifdef CONFIG_DEBUG_PAGEALLOC
/*
* Need to access the cpu field knowing that
* DEBUG_PAGEALLOC could have unmapped it if
* the mutex owner just released it and exited.
*/
if (probe_kernel_address(&owner->cpu, cpu))
goto out;
#else
cpu = owner->cpu;
#endif
/*
* Even if the access succeeded (likely case),
* the cpu field may no longer be valid.
*/
if (cpu >= nr_cpumask_bits)
goto out;
/*
* We need to validate that we can do a
* get_cpu() and that we have the percpu area.
*/
if (!cpu_online(cpu))
goto out;
rq = cpu_rq(cpu);
for (;;) {
/*
* Owner changed, break to re-assess state.
*/
if (lock->owner != owner)
break;
/*
* Is that owner really running on that cpu?
*/
if (task_thread_info(rq->curr) != owner || need_resched())
return 0;
cpu_relax();
}
out:
return 1;
}
#endif
#ifdef CONFIG_PREEMPT
/*
* this is the entry point to schedule() from in-kernel preemption

1
kernel/sched_features.h
View file

@ -14,3 +14,4 @@ SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
SCHED_FEAT(ASYM_EFF_LOAD, 1)
SCHED_FEAT(WAKEUP_OVERLAP, 0)
SCHED_FEAT(LAST_BUDDY, 1)
SCHED_FEAT(OWNER_SPIN, 1)

68
kernel/timer.c
View file

@ -491,14 +491,18 @@ static inline void debug_timer_free(struct timer_list *timer)
debug_object_free(timer, &timer_debug_descr);
}
static void __init_timer(struct timer_list *timer);
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
void init_timer_on_stack(struct timer_list *timer)
void init_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
debug_object_init_on_stack(timer, &timer_debug_descr);
__init_timer(timer);
__init_timer(timer, name, key);
}
EXPORT_SYMBOL_GPL(init_timer_on_stack);
EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
void destroy_timer_on_stack(struct timer_list *timer)
{
@ -512,7 +516,9 @@ static inline void debug_timer_activate(struct timer_list *timer) { }
static inline void debug_timer_deactivate(struct timer_list *timer) { }
#endif
static void __init_timer(struct timer_list *timer)
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
timer->entry.next = NULL;
timer->base = __raw_get_cpu_var(tvec_bases);
@ -521,6 +527,7 @@ static void __init_timer(struct timer_list *timer)
timer->start_pid = -1;
memset(timer->start_comm, 0, TASK_COMM_LEN);
#endif
lockdep_init_map(&timer->lockdep_map, name, key, 0);
}
/**
@ -530,19 +537,23 @@ static void __init_timer(struct timer_list *timer)
* init_timer() must be done to a timer prior calling *any* of the
* other timer functions.
*/
void init_timer(struct timer_list *timer)
void init_timer_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
debug_timer_init(timer);
__init_timer(timer);
__init_timer(timer, name, key);
}
EXPORT_SYMBOL(init_timer);
EXPORT_SYMBOL(init_timer_key);
void init_timer_deferrable(struct timer_list *timer)
void init_timer_deferrable_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
init_timer(timer);
init_timer_key(timer, name, key);
timer_set_deferrable(timer);
}
EXPORT_SYMBOL(init_timer_deferrable);
EXPORT_SYMBOL(init_timer_deferrable_key);
static inline void detach_timer(struct timer_list *timer,
int clear_pending)
@ -826,6 +837,15 @@ EXPORT_SYMBOL(try_to_del_timer_sync);
*/
int del_timer_sync(struct timer_list *timer)
{
#ifdef CONFIG_LOCKDEP
unsigned long flags;
local_irq_save(flags);
lock_map_acquire(&timer->lockdep_map);
lock_map_release(&timer->lockdep_map);
local_irq_restore(flags);
#endif
for (;;) {
int ret = try_to_del_timer_sync(timer);
if (ret >= 0)
@ -897,10 +917,36 @@ static inline void __run_timers(struct tvec_base *base)
set_running_timer(base, timer);
detach_timer(timer, 1);
spin_unlock_irq(&base->lock);
{
int preempt_count = preempt_count();
#ifdef CONFIG_LOCKDEP
/*
* It is permissible to free the timer from
* inside the function that is called from
* it, this we need to take into account for
* lockdep too. To avoid bogus "held lock
* freed" warnings as well as problems when
* looking into timer->lockdep_map, make a
* copy and use that here.
*/
struct lockdep_map lockdep_map =
timer->lockdep_map;
#endif
/*
* Couple the lock chain with the lock chain at
* del_timer_sync() by acquiring the lock_map
* around the fn() call here and in
* del_timer_sync().
*/
lock_map_acquire(&lockdep_map);
fn(data);
lock_map_release(&lockdep_map);
if (preempt_count != preempt_count()) {
printk(KERN_ERR "huh, entered %p "
"with preempt_count %08x, exited"

5
mm/page_alloc.c
View file

@ -1479,6 +1479,8 @@ __alloc_pages_internal(gfp_t gfp_mask, unsigned int order,
unsigned long did_some_progress;
unsigned long pages_reclaimed = 0;
lockdep_trace_alloc(gfp_mask);
might_sleep_if(wait);
if (should_fail_alloc_page(gfp_mask, order))
@ -1578,12 +1580,15 @@ nofail_alloc:
*/
cpuset_update_task_memory_state();
p->flags |= PF_MEMALLOC;
lockdep_set_current_reclaim_state(gfp_mask);
reclaim_state.reclaimed_slab = 0;
p->reclaim_state = &reclaim_state;
did_some_progress = try_to_free_pages(zonelist, order, gfp_mask);
p->reclaim_state = NULL;
lockdep_clear_current_reclaim_state();
p->flags &= ~PF_MEMALLOC;
cond_resched();

4
mm/slab.c
View file

@ -3318,6 +3318,8 @@ __cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
unsigned long save_flags;
void *ptr;
lockdep_trace_alloc(flags);
if (slab_should_failslab(cachep, flags))
return NULL;
@ -3394,6 +3396,8 @@ __cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller)
unsigned long save_flags;
void *objp;
lockdep_trace_alloc(flags);
if (slab_should_failslab(cachep, flags))
return NULL;

2
mm/slob.c
View file

@ -475,6 +475,8 @@ void *__kmalloc_node(size_t size, gfp_t gfp, int node)
unsigned int *m;
int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
lockdep_trace_alloc(gfp);
if (size < PAGE_SIZE - align) {
if (!size)
return ZERO_SIZE_PTR;

1
mm/slub.c
View file

@ -1590,6 +1590,7 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
unsigned long flags;
unsigned int objsize;
lockdep_trace_alloc(gfpflags);
might_sleep_if(gfpflags & __GFP_WAIT);
if (should_failslab(s->objsize, gfpflags))

2
mm/vmscan.c
View file

@ -1965,6 +1965,8 @@ static int kswapd(void *p)
};
node_to_cpumask_ptr(cpumask, pgdat->node_id);
lockdep_set_current_reclaim_state(GFP_KERNEL);
if (!cpumask_empty(cpumask))
set_cpus_allowed_ptr(tsk, cpumask);
current->reclaim_state = &reclaim_state;