Merge commit 'v2.6.29-rc7' into core/locking
diff --git a/Documentation/lockdep-design.txt b/Documentation/lockdep-design.txt
index 4887730..938ea22 100644
--- a/Documentation/lockdep-design.txt
+++ b/Documentation/lockdep-design.txt
@@ -27,33 +27,37 @@
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.
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 23bf02f..5a58ea3 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -20,43 +20,10 @@
#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 @@
* 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 @@
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 @@
# 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) \
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 7a0e5c4..3069ec7 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -50,8 +50,10 @@
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 list_head list;
struct task_struct *task;
#ifdef CONFIG_DEBUG_MUTEXES
- struct mutex *lock;
void *magic;
#endif
};
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8c216e0..a7faa8d0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -331,7 +331,9 @@
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;
@@ -1328,6 +1330,7 @@
int lockdep_depth;
unsigned int lockdep_recursion;
struct held_lock held_locks[MAX_LOCK_DEPTH];
+ gfp_t lockdep_reclaim_gfp;
#endif
/* journalling filesystem info */
diff --git a/include/linux/timer.h b/include/linux/timer.h
index daf9685..51774eb 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -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 @@
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);
}
/**
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 06b0c35..02014f7 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -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 @@
#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 @@
* 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 @@
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 @@
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 @@
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 @@
* 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 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;
- /*
- * 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 0;
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
return 1;
}
@@ -1861,9 +1900,9 @@
curr->comm, task_pid_nr(curr));
print_lock(this);
if (forwards)
- printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
+ printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
else
- printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
+ printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
print_lock_name(other);
printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
@@ -1933,7 +1972,7 @@
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 @@
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 +1988,95 @@
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,
+static int (*state_verbose_f[])(struct lock_class *class) = {
+#define LOCKDEP_STATE(__STATE) \
+ __STATE##_verbose,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+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,
enum lock_usage_bit new_bit)
{
- int ret = 1;
+ int excl_bit = exclusive_bit(new_bit);
+ int read = new_bit & 1;
+ int dir = new_bit & 2;
- switch(new_bit) {
- case LOCK_USED_IN_HARDIRQ:
- if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
+ /*
+ * 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 & ~1)))
+ 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 +2085,12 @@
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 +2144,7 @@
* 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 +2152,7 @@
* 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 +2232,7 @@
* enabled too:
*/
if (curr->hardirqs_enabled)
- mark_held_locks(curr, 0);
+ mark_held_locks(curr, SOFTIRQ);
}
/*
@@ -2317,6 +2261,31 @@
debug_atomic_inc(&redundant_softirqs_off);
}
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+ 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()))
+ return;
+
+ mark_held_locks(curr, RECLAIM_FS);
+}
+
static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
{
/*
@@ -2345,19 +2314,35 @@
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 +2397,10 @@
return 0;
}
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+}
+
#endif
/*
@@ -2445,14 +2434,13 @@
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 +2954,16 @@
}
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,
diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h
index 56b1969..a2cc7e9 100644
--- a/kernel/lockdep_internals.h
+++ b/kernel/lockdep_internals.h
@@ -7,6 +7,45 @@
*/
/*
+ * 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);
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index 13716b8..d7135aa 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -84,7 +84,7 @@
{
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 @@
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 @@
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_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",
diff --git a/kernel/lockdep_states.h b/kernel/lockdep_states.h
new file mode 100644
index 0000000..995b0cc
--- /dev/null
+++ b/kernel/lockdep_states.h
@@ -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)
diff --git a/kernel/mutex-debug.c b/kernel/mutex-debug.c
index 1d94160..50d022e 100644
--- a/kernel/mutex-debug.c
+++ b/kernel/mutex-debug.c
@@ -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 @@
/* 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 @@
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 @@
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;
}
diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h
index babfbdf..6b2d735 100644
--- a/kernel/mutex-debug.h
+++ b/kernel/mutex-debug.h
@@ -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_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); \
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 4f45d4b..5d79781 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -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 @@
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 @@
* 'unlocked' into 'locked' state.
*/
__mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
+ mutex_set_owner(lock);
}
EXPORT_SYMBOL(mutex_lock);
@@ -115,6 +122,14 @@
* 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 @@
{
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 @@
* 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 @@
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 @@
spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
+ preempt_enable();
return 0;
}
@@ -222,7 +292,8 @@
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 @@
wake_up_process(waiter->task);
}
- debug_mutex_clear_owner(lock);
-
spin_unlock_mutex(&lock->wait_lock, flags);
}
@@ -298,18 +367,30 @@
*/
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 @@
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 @@
*/
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);
diff --git a/kernel/mutex.h b/kernel/mutex.h
index a075daf..67578ca 100644
--- a/kernel/mutex.h
+++ b/kernel/mutex.h
@@ -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)
diff --git a/kernel/sched.c b/kernel/sched.c
index 8e2558c..faa63b9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4543,15 +4543,13 @@
/*
* 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);
@@ -4608,13 +4606,80 @@
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
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index da5d93b..07bc02e 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -13,3 +13,4 @@
SCHED_FEAT(ASYM_EFF_LOAD, 1)
SCHED_FEAT(WAKEUP_OVERLAP, 0)
SCHED_FEAT(LAST_BUDDY, 1)
+SCHED_FEAT(OWNER_SPIN, 1)
diff --git a/kernel/timer.c b/kernel/timer.c
index 13dd64f..ef1c385 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -491,14 +491,18 @@
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_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 @@
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 @@
* 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)
@@ -789,6 +800,15 @@
*/
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)
@@ -861,10 +881,36 @@
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"
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1bcf9cd..a0879b2 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -402,7 +402,7 @@
bool
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
select STACKTRACE
- select FRAME_POINTER if !X86 && !MIPS && !PPC
+ select FRAME_POINTER if !MIPS && !PPC
select KALLSYMS
select KALLSYMS_ALL
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5c44ed4..a3803ea 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1479,6 +1479,8 @@
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 @@
*/
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();
diff --git a/mm/slab.c b/mm/slab.c
index 4d00855..825c606 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3318,6 +3318,8 @@
unsigned long save_flags;
void *ptr;
+ lockdep_trace_alloc(flags);
+
if (slab_should_failslab(cachep, flags))
return NULL;
@@ -3394,6 +3396,8 @@
unsigned long save_flags;
void *objp;
+ lockdep_trace_alloc(flags);
+
if (slab_should_failslab(cachep, flags))
return NULL;
diff --git a/mm/slob.c b/mm/slob.c
index 52bc8a2..26aa464 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -464,6 +464,8 @@
unsigned int *m;
int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+ lockdep_trace_alloc(flags);
+
if (size < PAGE_SIZE - align) {
if (!size)
return ZERO_SIZE_PTR;
diff --git a/mm/slub.c b/mm/slub.c
index 0280eee..604da4b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1596,6 +1596,7 @@
unsigned long flags;
unsigned int objsize;
+ lockdep_trace_alloc(gfpflags);
might_sleep_if(gfpflags & __GFP_WAIT);
if (should_failslab(s->objsize, gfpflags))
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6177e3b..ae6f4c1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1965,6 +1965,8 @@
};
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;