*
* Started by Ingo Molnar:
*
- * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
*
* this code maps all the lock dependencies as they occur in a live kernel
* and will warn about the following classes of locking bugs:
* Thanks to Arjan van de Ven for coming up with the initial idea of
* mapping lock dependencies runtime.
*/
+#define DISABLE_BRANCH_PROFILING
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/debug_locks.h>
#include <linux/irqflags.h>
#include <linux/utsname.h>
+#include <linux/hash.h>
+#include <linux/ftrace.h>
+#include <linux/stringify.h>
+#include <linux/bitops.h>
#include <asm/sections.h>
#include "lockdep_internals.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/lockdep.h>
+
+#ifdef CONFIG_PROVE_LOCKING
+int prove_locking = 1;
+module_param(prove_locking, int, 0644);
+#else
+#define prove_locking 0
+#endif
+
+#ifdef CONFIG_LOCK_STAT
+int lock_stat = 1;
+module_param(lock_stat, int, 0644);
+#else
+#define lock_stat 0
+#endif
+
/*
* lockdep_lock: protects the lockdep graph, the hashes and the
* class/list/hash allocators.
__raw_spin_unlock(&lockdep_lock);
return 0;
}
+ /* prevent any recursions within lockdep from causing deadlocks */
+ current->lockdep_recursion++;
return 1;
}
if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
return DEBUG_LOCKS_WARN_ON(1);
+ current->lockdep_recursion--;
__raw_spin_unlock(&lockdep_lock);
return 0;
}
unsigned long nr_list_entries;
static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
-#ifdef CONFIG_PROVE_LOCKING
-/*
- * Allocate a lockdep entry. (assumes the graph_lock held, returns
- * with NULL on failure)
- */
-static struct lock_list *alloc_list_entry(void)
-{
- if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
- if (!debug_locks_off_graph_unlock())
- return NULL;
-
- printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
- printk("turning off the locking correctness validator.\n");
- return NULL;
- }
- return list_entries + nr_list_entries++;
-}
-#endif
-
/*
* All data structures here are protected by the global debug_lock.
*
unsigned long nr_lock_classes;
static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+static inline struct lock_class *hlock_class(struct held_lock *hlock)
+{
+ if (!hlock->class_idx) {
+ DEBUG_LOCKS_WARN_ON(1);
+ return NULL;
+ }
+ return lock_classes + hlock->class_idx - 1;
+}
+
+#ifdef CONFIG_LOCK_STAT
+static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
+
+static int lock_point(unsigned long points[], unsigned long ip)
+{
+ int i;
+
+ for (i = 0; i < LOCKSTAT_POINTS; i++) {
+ if (points[i] == 0) {
+ points[i] = ip;
+ break;
+ }
+ if (points[i] == ip)
+ break;
+ }
+
+ return i;
+}
+
+static void lock_time_inc(struct lock_time *lt, s64 time)
+{
+ if (time > lt->max)
+ lt->max = time;
+
+ if (time < lt->min || !lt->min)
+ lt->min = time;
+
+ lt->total += time;
+ lt->nr++;
+}
+
+static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
+{
+ dst->min += src->min;
+ dst->max += src->max;
+ dst->total += src->total;
+ dst->nr += src->nr;
+}
+
+struct lock_class_stats lock_stats(struct lock_class *class)
+{
+ struct lock_class_stats stats;
+ int cpu, i;
+
+ memset(&stats, 0, sizeof(struct lock_class_stats));
+ for_each_possible_cpu(cpu) {
+ struct lock_class_stats *pcs =
+ &per_cpu(lock_stats, cpu)[class - lock_classes];
+
+ for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
+ stats.contention_point[i] += pcs->contention_point[i];
+
+ for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
+ stats.contending_point[i] += pcs->contending_point[i];
+
+ lock_time_add(&pcs->read_waittime, &stats.read_waittime);
+ lock_time_add(&pcs->write_waittime, &stats.write_waittime);
+
+ lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
+ lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+
+ for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
+ stats.bounces[i] += pcs->bounces[i];
+ }
+
+ return stats;
+}
+
+void clear_lock_stats(struct lock_class *class)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct lock_class_stats *cpu_stats =
+ &per_cpu(lock_stats, cpu)[class - lock_classes];
+
+ memset(cpu_stats, 0, sizeof(struct lock_class_stats));
+ }
+ memset(class->contention_point, 0, sizeof(class->contention_point));
+ memset(class->contending_point, 0, sizeof(class->contending_point));
+}
+
+static struct lock_class_stats *get_lock_stats(struct lock_class *class)
+{
+ return &get_cpu_var(lock_stats)[class - lock_classes];
+}
+
+static void put_lock_stats(struct lock_class_stats *stats)
+{
+ put_cpu_var(lock_stats);
+}
+
+static void lock_release_holdtime(struct held_lock *hlock)
+{
+ struct lock_class_stats *stats;
+ s64 holdtime;
+
+ if (!lock_stat)
+ return;
+
+ holdtime = sched_clock() - hlock->holdtime_stamp;
+
+ stats = get_lock_stats(hlock_class(hlock));
+ if (hlock->read)
+ lock_time_inc(&stats->read_holdtime, holdtime);
+ else
+ lock_time_inc(&stats->write_holdtime, holdtime);
+ put_lock_stats(stats);
+}
+#else
+static inline void lock_release_holdtime(struct held_lock *hlock)
+{
+}
+#endif
+
/*
* We keep a global list of all lock classes. The list only grows,
* never shrinks. The list is only accessed with the lockdep
*/
#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
-#define CLASSHASH_MASK (CLASSHASH_SIZE - 1)
-#define __classhashfn(key) ((((unsigned long)key >> CLASSHASH_BITS) + (unsigned long)key) & CLASSHASH_MASK)
+#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
#define classhashentry(key) (classhash_table + __classhashfn((key)))
static struct list_head classhash_table[CLASSHASH_SIZE];
-unsigned long nr_lock_chains;
-#ifdef CONFIG_PROVE_LOCKING
-static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-#endif
-
/*
* We put the lock dependency chains into a hash-table as well, to cache
* their existence:
*/
#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
-#define CHAINHASH_MASK (CHAINHASH_SIZE - 1)
-#define __chainhashfn(chain) \
- (((chain >> CHAINHASH_BITS) + chain) & CHAINHASH_MASK)
+#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
static struct list_head chainhash_table[CHAINHASH_SIZE];
{
current->lockdep_recursion++;
}
-
EXPORT_SYMBOL(lockdep_off);
void lockdep_on(void)
{
current->lockdep_recursion--;
}
-
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:
*/
return 0;
}
-#ifdef CONFIG_TRACE_IRQFLAGS
-
-static int hardirq_verbose(struct lock_class *class)
-{
-#if HARDIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-static int softirq_verbose(struct lock_class *class)
-{
-#if SOFTIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-#endif
-
/*
* Stack-trace: tightly packed array of stack backtrace
* addresses. Protected by the graph_lock.
save_stack_trace(trace);
+ /*
+ * Some daft arches put -1 at the end to indicate its a full trace.
+ *
+ * <rant> this is buggy anyway, since it takes a whole extra entry so a
+ * complete trace that maxes out the entries provided will be reported
+ * as incomplete, friggin useless </rant>
+ */
+ if (trace->entries[trace->nr_entries-1] == ULONG_MAX)
+ trace->nr_entries--;
+
trace->max_entries = trace->nr_entries;
nr_stack_trace_entries += trace->nr_entries;
- if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
+ if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
if (!debug_locks_off_graph_unlock())
return 0;
unsigned int nr_softirq_chains;
unsigned int nr_process_chains;
unsigned int max_lockdep_depth;
-unsigned int max_recursion_depth;
#ifdef CONFIG_DEBUG_LOCKDEP
/*
* about it later on, in lockdep_info().
*/
static int lockdep_init_error;
+static unsigned long lockdep_init_trace_data[20];
+static struct stack_trace lockdep_init_trace = {
+ .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
+ .entries = lockdep_init_trace_data,
+};
/*
* Various lockdep statistics:
atomic_t redundant_softirqs_off;
atomic_t nr_unused_locks;
atomic_t nr_cyclic_checks;
-atomic_t nr_cyclic_check_recursions;
atomic_t nr_find_usage_forwards_checks;
-atomic_t nr_find_usage_forwards_recursions;
atomic_t nr_find_usage_backwards_checks;
-atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr) atomic_inc(ptr)
-# define debug_atomic_dec(ptr) atomic_dec(ptr)
-# define debug_atomic_read(ptr) atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr) do { } while (0)
-# define debug_atomic_dec(ptr) do { } while (0)
-# define debug_atomic_read(ptr) 0
#endif
/*
* 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)
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 = '.';
-
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
- *c1 = '+';
- else
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
- *c1 = '-';
+ return 1UL << bit;
+}
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
- *c2 = '+';
- else
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
- *c2 = '-';
+static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
+{
+ char c = '.';
- 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) {
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)
static void print_lock(struct held_lock *hlock)
{
- print_lock_name(hlock->class);
+ print_lock_name(hlock_class(hlock));
printk(", at: ");
print_ip_sym(hlock->acquire_ip);
}
int i, depth = curr->lockdep_depth;
if (!depth) {
- printk("no locks held by %s/%d.\n", curr->comm, curr->pid);
+ printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
return;
}
printk("%d lock%s held by %s/%d:\n",
- depth, depth > 1 ? "s" : "", curr->comm, curr->pid);
+ depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
for (i = 0; i < depth; i++) {
printk(" #%d: ", i);
}
}
-static void print_lock_class_header(struct lock_class *class, int depth)
+static void print_kernel_version(void)
{
- int bit;
-
- printk("%*s->", depth, "");
- print_lock_name(class);
- printk(" ops: %lu", class->ops);
- printk(" {\n");
-
- for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
- if (class->usage_mask & (1 << bit)) {
- int len = depth;
-
- len += printk("%*s %s", depth, "", usage_str[bit]);
- len += printk(" at:\n");
- print_stack_trace(class->usage_traces + bit, len);
- }
- }
- printk("%*s }\n", depth, "");
+ printk("%s %.*s\n", init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version);
+}
- printk("%*s ... key at: ",depth,"");
- print_ip_sym((unsigned long)class->key);
+static int very_verbose(struct lock_class *class)
+{
+#if VERY_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
}
/*
- * printk all lock dependencies starting at <entry>:
+ * Is this the address of a static object:
*/
-static void print_lock_dependencies(struct lock_class *class, int depth)
+static int static_obj(void *obj)
{
- struct lock_list *entry;
-
- if (DEBUG_LOCKS_WARN_ON(depth >= 20))
- return;
+ unsigned long start = (unsigned long) &_stext,
+ end = (unsigned long) &_end,
+ addr = (unsigned long) obj;
+#ifdef CONFIG_SMP
+ int i;
+#endif
- print_lock_class_header(class, depth);
+ /*
+ * static variable?
+ */
+ if ((addr >= start) && (addr < end))
+ return 1;
- list_for_each_entry(entry, &class->locks_after, entry) {
- if (DEBUG_LOCKS_WARN_ON(!entry->class))
- return;
+ if (arch_is_kernel_data(addr))
+ return 1;
- print_lock_dependencies(entry->class, depth + 1);
+#ifdef CONFIG_SMP
+ /*
+ * percpu var?
+ */
+ for_each_possible_cpu(i) {
+ start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
+ end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
+ + per_cpu_offset(i);
- printk("%*s ... acquired at:\n",depth,"");
- print_stack_trace(&entry->trace, 2);
- printk("\n");
+ if ((addr >= start) && (addr < end))
+ return 1;
}
+#endif
+
+ /*
+ * module var?
+ */
+ return is_module_address(addr);
}
-#ifdef CONFIG_PROVE_LOCKING
/*
- * Add a new dependency to the head of the list:
+ * To make lock name printouts unique, we calculate a unique
+ * class->name_version generation counter:
*/
-static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
- struct list_head *head, unsigned long ip, int distance)
+static int count_matching_names(struct lock_class *new_class)
{
- struct lock_list *entry;
- /*
- * Lock not present yet - get a new dependency struct and
- * add it to the list:
- */
- entry = alloc_list_entry();
- if (!entry)
- return 0;
+ struct lock_class *class;
+ int count = 0;
- entry->class = this;
- entry->distance = distance;
- if (!save_trace(&entry->trace))
+ if (!new_class->name)
return 0;
- /*
- * Since we never remove from the dependency list, the list can
- * be walked lockless by other CPUs, it's only allocation
- * that must be protected by the spinlock. But this also means
- * we must make new entries visible only once writes to the
- * entry become visible - hence the RCU op:
- */
- list_add_tail_rcu(&entry->entry, head);
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ if (new_class->key - new_class->subclass == class->key)
+ return class->name_version;
+ if (class->name && !strcmp(class->name, new_class->name))
+ count = max(count, class->name_version);
+ }
- return 1;
+ return count + 1;
}
/*
- * Recursive, forwards-direction lock-dependency checking, used for
- * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
- * checking.
- *
- * (to keep the stackframe of the recursive functions small we
- * use these global variables, and we also mark various helper
- * functions as noinline.)
- */
-static struct held_lock *check_source, *check_target;
-
-/*
- * Print a dependency chain entry (this is only done when a deadlock
- * has been detected):
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
*/
-static noinline int
-print_circular_bug_entry(struct lock_list *target, unsigned int depth)
+static inline struct lock_class *
+look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
{
- if (debug_locks_silent)
- return 0;
- printk("\n-> #%u", depth);
- print_lock_name(target->class);
- printk(":\n");
- print_stack_trace(&target->trace, 6);
-
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ /*
+ * If the architecture calls into lockdep before initializing
+ * the hashes then we'll warn about it later. (we cannot printk
+ * right now)
+ */
+ if (unlikely(!lockdep_initialized)) {
+ lockdep_init();
+ lockdep_init_error = 1;
+ save_stack_trace(&lockdep_init_trace);
+ }
+#endif
+
+ /*
+ * Static locks do not have their class-keys yet - for them the key
+ * is the lock object itself:
+ */
+ if (unlikely(!lock->key))
+ lock->key = (void *)lock;
+
+ /*
+ * NOTE: the class-key must be unique. For dynamic locks, a static
+ * lock_class_key variable is passed in through the mutex_init()
+ * (or spin_lock_init()) call - which acts as the key. For static
+ * locks we use the lock object itself as the key.
+ */
+ BUILD_BUG_ON(sizeof(struct lock_class_key) >
+ sizeof(struct lockdep_map));
+
+ key = lock->key->subkeys + subclass;
+
+ hash_head = classhashentry(key);
+
+ /*
+ * We can walk the hash lockfree, because the hash only
+ * grows, and we are careful when adding entries to the end:
+ */
+ list_for_each_entry(class, hash_head, hash_entry) {
+ if (class->key == key) {
+ WARN_ON_ONCE(class->name != lock->name);
+ return class;
+ }
+ }
+
+ return NULL;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+ unsigned long flags;
+
+ class = look_up_lock_class(lock, subclass);
+ if (likely(class))
+ return class;
+
+ /*
+ * Debug-check: all keys must be persistent!
+ */
+ if (!static_obj(lock->key)) {
+ debug_locks_off();
+ printk("INFO: trying to register non-static key.\n");
+ printk("the code is fine but needs lockdep annotation.\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+
+ return NULL;
+ }
+
+ key = lock->key->subkeys + subclass;
+ hash_head = classhashentry(key);
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ /*
+ * We have to do the hash-walk again, to avoid races
+ * with another CPU:
+ */
+ list_for_each_entry(class, hash_head, hash_entry)
+ if (class->key == key)
+ goto out_unlock_set;
+ /*
+ * Allocate a new key from the static array, and add it to
+ * the hash:
+ */
+ if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
+ if (!debug_locks_off_graph_unlock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ raw_local_irq_restore(flags);
+
+ printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+ return NULL;
+ }
+ class = lock_classes + nr_lock_classes++;
+ debug_atomic_inc(&nr_unused_locks);
+ class->key = key;
+ class->name = lock->name;
+ class->subclass = subclass;
+ INIT_LIST_HEAD(&class->lock_entry);
+ INIT_LIST_HEAD(&class->locks_before);
+ INIT_LIST_HEAD(&class->locks_after);
+ class->name_version = count_matching_names(class);
+ /*
+ * We use RCU's safe list-add method to make
+ * parallel walking of the hash-list safe:
+ */
+ list_add_tail_rcu(&class->hash_entry, hash_head);
+ /*
+ * Add it to the global list of classes:
+ */
+ list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
+
+ if (verbose(class)) {
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+ printk("\nnew class %p: %s", class->key, class->name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ printk("\n");
+ dump_stack();
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ }
+out_unlock_set:
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+ if (!subclass || force)
+ lock->class_cache = class;
+
+ if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+ return NULL;
+
+ return class;
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+/*
+ * Allocate a lockdep entry. (assumes the graph_lock held, returns
+ * with NULL on failure)
+ */
+static struct lock_list *alloc_list_entry(void)
+{
+ if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
+ if (!debug_locks_off_graph_unlock())
+ return NULL;
+
+ printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+ return NULL;
+ }
+ return list_entries + nr_list_entries++;
+}
+
+/*
+ * Add a new dependency to the head of the list:
+ */
+static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
+ struct list_head *head, unsigned long ip, int distance)
+{
+ struct lock_list *entry;
+ /*
+ * Lock not present yet - get a new dependency struct and
+ * add it to the list:
+ */
+ entry = alloc_list_entry();
+ if (!entry)
+ return 0;
+
+ if (!save_trace(&entry->trace))
+ return 0;
+
+ entry->class = this;
+ entry->distance = distance;
+ /*
+ * Since we never remove from the dependency list, the list can
+ * be walked lockless by other CPUs, it's only allocation
+ * that must be protected by the spinlock. But this also means
+ * we must make new entries visible only once writes to the
+ * entry become visible - hence the RCU op:
+ */
+ list_add_tail_rcu(&entry->entry, head);
+
+ return 1;
+}
+
+/*
+ * For good efficiency of modular, we use power of 2
+ */
+#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
+#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
+
+/*
+ * The circular_queue and helpers is used to implement the
+ * breadth-first search(BFS)algorithem, by which we can build
+ * the shortest path from the next lock to be acquired to the
+ * previous held lock if there is a circular between them.
+ */
+struct circular_queue {
+ unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
+ unsigned int front, rear;
+};
+
+static struct circular_queue lock_cq;
+
+unsigned int max_bfs_queue_depth;
+
+static unsigned int lockdep_dependency_gen_id;
+
+static inline void __cq_init(struct circular_queue *cq)
+{
+ cq->front = cq->rear = 0;
+ lockdep_dependency_gen_id++;
+}
+
+static inline int __cq_empty(struct circular_queue *cq)
+{
+ return (cq->front == cq->rear);
+}
+
+static inline int __cq_full(struct circular_queue *cq)
+{
+ return ((cq->rear + 1) & CQ_MASK) == cq->front;
+}
+
+static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
+{
+ if (__cq_full(cq))
+ return -1;
+
+ cq->element[cq->rear] = elem;
+ cq->rear = (cq->rear + 1) & CQ_MASK;
return 0;
}
-#endif
-static void print_kernel_version(void)
+static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
+{
+ if (__cq_empty(cq))
+ return -1;
+
+ *elem = cq->element[cq->front];
+ cq->front = (cq->front + 1) & CQ_MASK;
+ return 0;
+}
+
+static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
+{
+ return (cq->rear - cq->front) & CQ_MASK;
+}
+
+static inline void mark_lock_accessed(struct lock_list *lock,
+ struct lock_list *parent)
+{
+ unsigned long nr;
+
+ nr = lock - list_entries;
+ WARN_ON(nr >= nr_list_entries);
+ lock->parent = parent;
+ lock->class->dep_gen_id = lockdep_dependency_gen_id;
+}
+
+static inline unsigned long lock_accessed(struct lock_list *lock)
+{
+ unsigned long nr;
+
+ nr = lock - list_entries;
+ WARN_ON(nr >= nr_list_entries);
+ return lock->class->dep_gen_id == lockdep_dependency_gen_id;
+}
+
+static inline struct lock_list *get_lock_parent(struct lock_list *child)
+{
+ return child->parent;
+}
+
+static inline int get_lock_depth(struct lock_list *child)
+{
+ int depth = 0;
+ struct lock_list *parent;
+
+ while ((parent = get_lock_parent(child))) {
+ child = parent;
+ depth++;
+ }
+ return depth;
+}
+
+static int __bfs(struct lock_list *source_entry,
+ void *data,
+ int (*match)(struct lock_list *entry, void *data),
+ struct lock_list **target_entry,
+ int forward)
+{
+ struct lock_list *entry;
+ struct list_head *head;
+ struct circular_queue *cq = &lock_cq;
+ int ret = 1;
+
+ if (match(source_entry, data)) {
+ *target_entry = source_entry;
+ ret = 0;
+ goto exit;
+ }
+
+ if (forward)
+ head = &source_entry->class->locks_after;
+ else
+ head = &source_entry->class->locks_before;
+
+ if (list_empty(head))
+ goto exit;
+
+ __cq_init(cq);
+ __cq_enqueue(cq, (unsigned long)source_entry);
+
+ while (!__cq_empty(cq)) {
+ struct lock_list *lock;
+
+ __cq_dequeue(cq, (unsigned long *)&lock);
+
+ if (!lock->class) {
+ ret = -2;
+ goto exit;
+ }
+
+ if (forward)
+ head = &lock->class->locks_after;
+ else
+ head = &lock->class->locks_before;
+
+ list_for_each_entry(entry, head, entry) {
+ if (!lock_accessed(entry)) {
+ unsigned int cq_depth;
+ mark_lock_accessed(entry, lock);
+ if (match(entry, data)) {
+ *target_entry = entry;
+ ret = 0;
+ goto exit;
+ }
+
+ if (__cq_enqueue(cq, (unsigned long)entry)) {
+ ret = -1;
+ goto exit;
+ }
+ cq_depth = __cq_get_elem_count(cq);
+ if (max_bfs_queue_depth < cq_depth)
+ max_bfs_queue_depth = cq_depth;
+ }
+ }
+ }
+exit:
+ return ret;
+}
+
+static inline int __bfs_forwards(struct lock_list *src_entry,
+ void *data,
+ int (*match)(struct lock_list *entry, void *data),
+ struct lock_list **target_entry)
+{
+ return __bfs(src_entry, data, match, target_entry, 1);
+
+}
+
+static inline int __bfs_backwards(struct lock_list *src_entry,
+ void *data,
+ int (*match)(struct lock_list *entry, void *data),
+ struct lock_list **target_entry)
+{
+ return __bfs(src_entry, data, match, target_entry, 0);
+
+}
+
+/*
+ * Recursive, forwards-direction lock-dependency checking, used for
+ * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
+ * checking.
+ */
+
+/*
+ * Print a dependency chain entry (this is only done when a deadlock
+ * has been detected):
+ */
+static noinline int
+print_circular_bug_entry(struct lock_list *target, int depth)
{
- printk("%s %.*s\n", init_utsname()->release,
- (int)strcspn(init_utsname()->version, " "),
- init_utsname()->version);
+ if (debug_locks_silent)
+ return 0;
+ printk("\n-> #%u", depth);
+ print_lock_name(target->class);
+ printk(":\n");
+ print_stack_trace(&target->trace, 6);
+
+ return 0;
}
-#ifdef CONFIG_PROVE_LOCKING
/*
* When a circular dependency is detected, print the
* header first:
*/
static noinline int
-print_circular_bug_header(struct lock_list *entry, unsigned int depth)
+print_circular_bug_header(struct lock_list *entry, unsigned int depth,
+ struct held_lock *check_src,
+ struct held_lock *check_tgt)
{
struct task_struct *curr = current;
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ if (debug_locks_silent)
return 0;
printk("\n=======================================================\n");
print_kernel_version();
printk( "-------------------------------------------------------\n");
printk("%s/%d is trying to acquire lock:\n",
- curr->comm, curr->pid);
- print_lock(check_source);
+ curr->comm, task_pid_nr(curr));
+ print_lock(check_src);
printk("\nbut task is already holding lock:\n");
- print_lock(check_target);
+ print_lock(check_tgt);
printk("\nwhich lock already depends on the new lock.\n\n");
printk("\nthe existing dependency chain (in reverse order) is:\n");
return 0;
}
-static noinline int print_circular_bug_tail(void)
+static inline int class_equal(struct lock_list *entry, void *data)
+{
+ return entry->class == data;
+}
+
+static noinline int print_circular_bug(struct lock_list *this,
+ struct lock_list *target,
+ struct held_lock *check_src,
+ struct held_lock *check_tgt)
{
struct task_struct *curr = current;
- struct lock_list this;
+ struct lock_list *parent;
+ int depth;
- if (debug_locks_silent)
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;
- this.class = check_source->class;
- if (!save_trace(&this.trace))
+ if (!save_trace(&this->trace))
return 0;
- print_circular_bug_entry(&this, 0);
+ depth = get_lock_depth(target);
+
+ print_circular_bug_header(target, depth, check_src, check_tgt);
+
+ parent = get_lock_parent(target);
+
+ while (parent) {
+ print_circular_bug_entry(parent, --depth);
+ parent = get_lock_parent(parent);
+ }
printk("\nother info that might help us debug this:\n\n");
lockdep_print_held_locks(curr);
return 0;
}
-#define RECURSION_LIMIT 40
-
-static int noinline print_infinite_recursion_bug(void)
+static noinline int print_bfs_bug(int ret)
{
if (!debug_locks_off_graph_unlock())
return 0;
- WARN_ON(1);
+ WARN(1, "lockdep bfs error:%d\n", ret);
+
+ return 0;
+}
+static int noop_count(struct lock_list *entry, void *data)
+{
+ (*(unsigned long *)data)++;
return 0;
}
+unsigned long __lockdep_count_forward_deps(struct lock_list *this)
+{
+ unsigned long count = 0;
+ struct lock_list *uninitialized_var(target_entry);
+
+ __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
+
+ return count;
+}
+unsigned long lockdep_count_forward_deps(struct lock_class *class)
+{
+ unsigned long ret, flags;
+ struct lock_list this;
+
+ this.parent = NULL;
+ this.class = class;
+
+ local_irq_save(flags);
+ __raw_spin_lock(&lockdep_lock);
+ ret = __lockdep_count_forward_deps(&this);
+ __raw_spin_unlock(&lockdep_lock);
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+unsigned long __lockdep_count_backward_deps(struct lock_list *this)
+{
+ unsigned long count = 0;
+ struct lock_list *uninitialized_var(target_entry);
+
+ __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
+
+ return count;
+}
+
+unsigned long lockdep_count_backward_deps(struct lock_class *class)
+{
+ unsigned long ret, flags;
+ struct lock_list this;
+
+ this.parent = NULL;
+ this.class = class;
+
+ local_irq_save(flags);
+ __raw_spin_lock(&lockdep_lock);
+ ret = __lockdep_count_backward_deps(&this);
+ __raw_spin_unlock(&lockdep_lock);
+ local_irq_restore(flags);
+
+ return ret;
+}
+
/*
* Prove that the dependency graph starting at <entry> can not
* lead to <target>. Print an error and return 0 if it does.
*/
static noinline int
-check_noncircular(struct lock_class *source, unsigned int depth)
+check_noncircular(struct lock_list *root, struct lock_class *target,
+ struct lock_list **target_entry)
{
- struct lock_list *entry;
+ int result;
- debug_atomic_inc(&nr_cyclic_check_recursions);
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_after, entry) {
- if (entry->class == check_target->class)
- return print_circular_bug_header(entry, depth+1);
- debug_atomic_inc(&nr_cyclic_checks);
- if (!check_noncircular(entry->class, depth+1))
- return print_circular_bug_entry(entry, depth+1);
- }
- return 1;
-}
-#endif
+ debug_atomic_inc(&nr_cyclic_checks);
-static int very_verbose(struct lock_class *class)
-{
-#if VERY_VERBOSE
- return class_filter(class);
-#endif
- return 0;
+ result = __bfs_forwards(root, target, class_equal, target_entry);
+
+ return result;
}
-#ifdef CONFIG_TRACE_IRQFLAGS
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
/*
* Forwards and backwards subgraph searching, for the purposes of
* proving that two subgraphs can be connected by a new dependency
* without creating any illegal irq-safe -> irq-unsafe lock dependency.
*/
-static enum lock_usage_bit find_usage_bit;
-static struct lock_class *forwards_match, *backwards_match;
+
+static inline int usage_match(struct lock_list *entry, void *bit)
+{
+ return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
+}
+
+
/*
* Find a node in the forwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
+ * at @root->class that matches @bit.
*
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <forwards_match>.
+ * Return 0 if such a node exists in the subgraph, and put that node
+ * into *@target_entry.
*
- * Return 1 otherwise and keep <forwards_match> unchanged.
- * Return 0 on error.
+ * Return 1 otherwise and keep *@target_entry unchanged.
+ * Return <0 on error.
*/
-static noinline int
-find_usage_forwards(struct lock_class *source, unsigned int depth)
+static int
+find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
+ struct lock_list **target_entry)
{
- struct lock_list *entry;
- int ret;
-
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
+ int result;
debug_atomic_inc(&nr_find_usage_forwards_checks);
- if (source->usage_mask & (1 << find_usage_bit)) {
- forwards_match = source;
- return 2;
- }
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_after, entry) {
- debug_atomic_inc(&nr_find_usage_forwards_recursions);
- ret = find_usage_forwards(entry->class, depth+1);
- if (ret == 2 || ret == 0)
- return ret;
- }
- return 1;
+ result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
+
+ return result;
}
/*
* Find a node in the backwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
+ * at @root->class that matches @bit.
*
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <backwards_match>.
+ * Return 0 if such a node exists in the subgraph, and put that node
+ * into *@target_entry.
*
- * Return 1 otherwise and keep <backwards_match> unchanged.
- * Return 0 on error.
+ * Return 1 otherwise and keep *@target_entry unchanged.
+ * Return <0 on error.
*/
-static noinline int
-find_usage_backwards(struct lock_class *source, unsigned int depth)
+static int
+find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
+ struct lock_list **target_entry)
{
- struct lock_list *entry;
- int ret;
+ int result;
- if (!__raw_spin_is_locked(&lockdep_lock))
- return DEBUG_LOCKS_WARN_ON(1);
+ debug_atomic_inc(&nr_find_usage_backwards_checks);
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
+ result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
- debug_atomic_inc(&nr_find_usage_backwards_checks);
- if (source->usage_mask & (1 << find_usage_bit)) {
- backwards_match = source;
- return 2;
- }
+ return result;
+}
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_before, entry) {
- debug_atomic_inc(&nr_find_usage_backwards_recursions);
- ret = find_usage_backwards(entry->class, depth+1);
- if (ret == 2 || ret == 0)
- return ret;
+static void print_lock_class_header(struct lock_class *class, int depth)
+{
+ int bit;
+
+ printk("%*s->", depth, "");
+ print_lock_name(class);
+ printk(" ops: %lu", class->ops);
+ printk(" {\n");
+
+ for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
+ if (class->usage_mask & (1 << bit)) {
+ int len = depth;
+
+ len += printk("%*s %s", depth, "", usage_str[bit]);
+ len += printk(" at:\n");
+ print_stack_trace(class->usage_traces + bit, len);
+ }
}
- return 1;
+ printk("%*s }\n", depth, "");
+
+ printk("%*s ... key at: ",depth,"");
+ print_ip_sym((unsigned long)class->key);
+}
+
+/*
+ * printk the shortest lock dependencies from @start to @end in reverse order:
+ */
+static void __used
+print_shortest_lock_dependencies(struct lock_list *leaf,
+ struct lock_list *root)
+{
+ struct lock_list *entry = leaf;
+ int depth;
+
+ /*compute depth from generated tree by BFS*/
+ depth = get_lock_depth(leaf);
+
+ do {
+ print_lock_class_header(entry->class, depth);
+ printk("%*s ... acquired at:\n", depth, "");
+ print_stack_trace(&entry->trace, 2);
+ printk("\n");
+
+ if (depth == 0 && (entry != root)) {
+ printk("lockdep:%s bad BFS generated tree\n", __func__);
+ break;
+ }
+
+ entry = get_lock_parent(entry);
+ depth--;
+ } while (entry && (depth >= 0));
+
+ return;
}
static int
print_bad_irq_dependency(struct task_struct *curr,
+ struct lock_list *prev_root,
+ struct lock_list *next_root,
+ struct lock_list *backwards_entry,
+ struct lock_list *forwards_entry,
struct held_lock *prev,
struct held_lock *next,
enum lock_usage_bit bit1,
print_kernel_version();
printk( "------------------------------------------------------\n");
printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
- curr->comm, curr->pid,
+ curr->comm, task_pid_nr(curr),
curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
curr->hardirqs_enabled,
printk("\nand this task is already holding:\n");
print_lock(prev);
printk("which would create a new lock dependency:\n");
- print_lock_name(prev->class);
+ print_lock_name(hlock_class(prev));
printk(" ->");
- print_lock_name(next->class);
+ print_lock_name(hlock_class(next));
printk("\n");
printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
irqclass);
- print_lock_name(backwards_match);
+ print_lock_name(backwards_entry->class);
printk("\n... which became %s-irq-safe at:\n", irqclass);
- print_stack_trace(backwards_match->usage_traces + bit1, 1);
+ print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
printk("\nto a %s-irq-unsafe lock:\n", irqclass);
- print_lock_name(forwards_match);
+ print_lock_name(forwards_entry->class);
printk("\n... which became %s-irq-unsafe at:\n", irqclass);
printk("...");
- print_stack_trace(forwards_match->usage_traces + bit2, 1);
+ print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
printk("\nother info that might help us debug this:\n\n");
lockdep_print_held_locks(curr);
- printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass);
- print_lock_dependencies(backwards_match, 0);
+ printk("\nthe dependencies between %s-irq-safe lock", irqclass);
+ printk(" and the holding lock:\n");
+ if (!save_trace(&prev_root->trace))
+ return 0;
+ print_shortest_lock_dependencies(backwards_entry, prev_root);
- printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass);
- print_lock_dependencies(forwards_match, 0);
+ printk("\nthe dependencies between the lock to be acquired");
+ printk(" and %s-irq-unsafe lock:\n", irqclass);
+ if (!save_trace(&next_root->trace))
+ return 0;
+ print_shortest_lock_dependencies(forwards_entry, next_root);
printk("\nstack backtrace:\n");
dump_stack();
enum lock_usage_bit bit_forwards, const char *irqclass)
{
int ret;
+ struct lock_list this, that;
+ struct lock_list *uninitialized_var(target_entry);
+ struct lock_list *uninitialized_var(target_entry1);
- find_usage_bit = bit_backwards;
- /* fills in <backwards_match> */
- ret = find_usage_backwards(prev->class, 0);
- if (!ret || ret == 1)
+ this.parent = NULL;
+
+ this.class = hlock_class(prev);
+ ret = find_usage_backwards(&this, bit_backwards, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- find_usage_bit = bit_forwards;
- ret = find_usage_forwards(next->class, 0);
- if (!ret || ret == 1)
+ that.parent = NULL;
+ that.class = hlock_class(next);
+ ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- /* ret == 2 */
- return print_bad_irq_dependency(curr, prev, next,
+
+ return print_bad_irq_dependency(curr, &this, &that,
+ target_entry, target_entry1,
+ prev, next,
bit_backwards, bit_forwards, irqclass);
}
+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
+ * 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, 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, bit,
+ exclusive_bit(bit), state_name(bit)))
+ return 0;
+
+ 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;
+}
+
+static void inc_chains(void)
+{
+ if (current->hardirq_context)
+ nr_hardirq_chains++;
+ else {
+ if (current->softirq_context)
+ nr_softirq_chains++;
+ else
+ nr_process_chains++;
+ }
+}
+
+#else
+
+static inline int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ return 1;
+}
+
+static inline void inc_chains(void)
+{
+ nr_process_chains++;
+}
+
#endif
-#ifdef CONFIG_PROVE_LOCKING
static int
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
print_kernel_version();
printk( "---------------------------------------------\n");
printk("%s/%d is trying to acquire lock:\n",
- curr->comm, curr->pid);
+ curr->comm, task_pid_nr(curr));
print_lock(next);
printk("\nbut task is already holding lock:\n");
print_lock(prev);
struct lockdep_map *next_instance, int read)
{
struct held_lock *prev;
+ struct held_lock *nest = NULL;
int i;
for (i = 0; i < curr->lockdep_depth; i++) {
prev = curr->held_locks + i;
- if (prev->class != next->class)
+
+ if (prev->instance == next->nest_lock)
+ nest = prev;
+
+ if (hlock_class(prev) != hlock_class(next))
continue;
+
/*
* Allow read-after-read recursion of the same
* lock class (i.e. read_lock(lock)+read_lock(lock)):
*/
if ((read == 2) && prev->read)
return 2;
+
+ /*
+ * We're holding the nest_lock, which serializes this lock's
+ * nesting behaviour.
+ */
+ if (nest)
+ return 2;
+
return print_deadlock_bug(curr, prev, next);
}
return 1;
{
struct lock_list *entry;
int ret;
+ struct lock_list this;
+ struct lock_list *uninitialized_var(target_entry);
/*
- * Prove that the new <prev> -> <next> dependency would not
- * create a circular dependency in the graph. (We do this by
- * forward-recursing into the graph starting at <next>, and
- * checking whether we can reach <prev>.)
- *
- * We are using global variables to control the recursion, to
- * keep the stackframe size of the recursive functions low:
- */
- check_source = next;
- check_target = prev;
- if (!(check_noncircular(next->class, 0)))
- return print_circular_bug_tail();
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- /*
- * Prove that the new dependency does not connect a hardirq-safe
- * 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,
- LOCK_ENABLED_HARDIRQS, "hard"))
- return 0;
-
- /*
- * 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"))
- 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>:
+ * Prove that the new <prev> -> <next> dependency would not
+ * create a circular dependency in the graph. (We do this by
+ * forward-recursing into the graph starting at <next>, and
+ * checking whether we can reach <prev>.)
+ *
+ * We are using global variables to control the recursion, to
+ * keep the stackframe size of the recursive functions low:
*/
- if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
- LOCK_ENABLED_SOFTIRQS, "soft"))
+ this.class = hlock_class(next);
+ this.parent = NULL;
+ ret = check_noncircular(&this, hlock_class(prev), &target_entry);
+ if (unlikely(!ret))
+ return print_circular_bug(&this, target_entry, next, prev);
+ else if (unlikely(ret < 0))
+ return print_bfs_bug(ret);
+
+ if (!check_prev_add_irq(curr, prev, next))
return 0;
-#endif
+
/*
* For recursive read-locks we do all the dependency checks,
* but we dont store read-triggered dependencies (only
* chains - the second one will be new, but L1 already has
* L2 added to its dependency list, due to the first chain.)
*/
- list_for_each_entry(entry, &prev->class->locks_after, entry) {
- if (entry->class == next->class) {
+ list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
+ if (entry->class == hlock_class(next)) {
if (distance == 1)
entry->distance = 1;
return 2;
* Ok, all validations passed, add the new lock
* to the previous lock's dependency list:
*/
- ret = add_lock_to_list(prev->class, next->class,
- &prev->class->locks_after, next->acquire_ip, distance);
+ ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
+ &hlock_class(prev)->locks_after,
+ next->acquire_ip, distance);
if (!ret)
return 0;
- ret = add_lock_to_list(next->class, prev->class,
- &next->class->locks_before, next->acquire_ip, distance);
+ ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
+ &hlock_class(next)->locks_before,
+ next->acquire_ip, distance);
if (!ret)
return 0;
/*
* Debugging printouts:
*/
- if (verbose(prev->class) || verbose(next->class)) {
+ if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
graph_unlock();
printk("\n new dependency: ");
- print_lock_name(prev->class);
+ print_lock_name(hlock_class(prev));
printk(" => ");
- print_lock_name(next->class);
+ print_lock_name(hlock_class(next));
printk("\n");
dump_stack();
return graph_lock();
return 0;
}
-#endif
-
-/*
- * Is this the address of a static object:
- */
-static int static_obj(void *obj)
-{
- unsigned long start = (unsigned long) &_stext,
- end = (unsigned long) &_end,
- addr = (unsigned long) obj;
-#ifdef CONFIG_SMP
- int i;
-#endif
-
- /*
- * static variable?
- */
- if ((addr >= start) && (addr < end))
- return 1;
-
-#ifdef CONFIG_SMP
- /*
- * percpu var?
- */
- for_each_possible_cpu(i) {
- start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
- end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
- + per_cpu_offset(i);
-
- if ((addr >= start) && (addr < end))
- return 1;
- }
-#endif
-
- /*
- * module var?
- */
- return is_module_address(addr);
-}
-
-/*
- * To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
- */
-static int count_matching_names(struct lock_class *new_class)
-{
- struct lock_class *class;
- int count = 0;
-
- if (!new_class->name)
- return 0;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
- if (new_class->key - new_class->subclass == class->key)
- return class->name_version;
- if (class->name && !strcmp(class->name, new_class->name))
- count = max(count, class->name_version);
- }
-
- return count + 1;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- /*
- * If the architecture calls into lockdep before initializing
- * the hashes then we'll warn about it later. (we cannot printk
- * right now)
- */
- if (unlikely(!lockdep_initialized)) {
- lockdep_init();
- lockdep_init_error = 1;
- }
-#endif
- /*
- * Static locks do not have their class-keys yet - for them the key
- * is the lock object itself:
- */
- if (unlikely(!lock->key))
- lock->key = (void *)lock;
-
- /*
- * NOTE: the class-key must be unique. For dynamic locks, a static
- * lock_class_key variable is passed in through the mutex_init()
- * (or spin_lock_init()) call - which acts as the key. For static
- * locks we use the lock object itself as the key.
- */
- BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class));
-
- key = lock->key->subkeys + subclass;
-
- hash_head = classhashentry(key);
-
- /*
- * We can walk the hash lockfree, because the hash only
- * grows, and we are careful when adding entries to the end:
- */
- list_for_each_entry(class, hash_head, hash_entry)
- if (class->key == key)
- return class;
-
- return NULL;
-}
+unsigned long nr_lock_chains;
+struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
+int nr_chain_hlocks;
+static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
+struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
- unsigned long flags;
-
- class = look_up_lock_class(lock, subclass);
- if (likely(class))
- return class;
-
- /*
- * Debug-check: all keys must be persistent!
- */
- if (!static_obj(lock->key)) {
- debug_locks_off();
- printk("INFO: trying to register non-static key.\n");
- printk("the code is fine but needs lockdep annotation.\n");
- printk("turning off the locking correctness validator.\n");
- dump_stack();
-
- return NULL;
- }
-
- key = lock->key->subkeys + subclass;
- hash_head = classhashentry(key);
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- /*
- * We have to do the hash-walk again, to avoid races
- * with another CPU:
- */
- list_for_each_entry(class, hash_head, hash_entry)
- if (class->key == key)
- goto out_unlock_set;
- /*
- * Allocate a new key from the static array, and add it to
- * the hash:
- */
- if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
- if (!debug_locks_off_graph_unlock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- raw_local_irq_restore(flags);
-
- printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
- printk("turning off the locking correctness validator.\n");
- return NULL;
- }
- class = lock_classes + nr_lock_classes++;
- debug_atomic_inc(&nr_unused_locks);
- class->key = key;
- class->name = lock->name;
- class->subclass = subclass;
- INIT_LIST_HEAD(&class->lock_entry);
- INIT_LIST_HEAD(&class->locks_before);
- INIT_LIST_HEAD(&class->locks_after);
- class->name_version = count_matching_names(class);
- /*
- * We use RCU's safe list-add method to make
- * parallel walking of the hash-list safe:
- */
- list_add_tail_rcu(&class->hash_entry, hash_head);
-
- if (verbose(class)) {
- graph_unlock();
- raw_local_irq_restore(flags);
-
- printk("\nnew class %p: %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- }
-out_unlock_set:
- graph_unlock();
- raw_local_irq_restore(flags);
-
- if (!subclass || force)
- lock->class_cache = class;
-
- if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
- return NULL;
-
- return class;
+ return lock_classes + chain_hlocks[chain->base + i];
}
-#ifdef CONFIG_PROVE_LOCKING
/*
* Look up a dependency chain. If the key is not present yet then
* add it and return 1 - in this case the new dependency chain is
* validated. If the key is already hashed, return 0.
* (On return with 1 graph_lock is held.)
*/
-static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
+static inline int lookup_chain_cache(struct task_struct *curr,
+ struct held_lock *hlock,
+ u64 chain_key)
{
+ struct lock_class *class = hlock_class(hlock);
struct list_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
+ struct held_lock *hlock_curr, *hlock_next;
+ int i, j, n, cn;
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return 0;
if (!debug_locks_off_graph_unlock())
return 0;
- printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
- printk("turning off the locking correctness validator.\n");
- return 0;
- }
- chain = lock_chains + nr_lock_chains++;
- chain->chain_key = chain_key;
- list_add_tail_rcu(&chain->entry, hash_head);
- debug_atomic_inc(&chain_lookup_misses);
-#ifdef CONFIG_TRACE_IRQFLAGS
- if (current->hardirq_context)
- nr_hardirq_chains++;
- else {
- if (current->softirq_context)
- nr_softirq_chains++;
- else
- nr_process_chains++;
- }
+ printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+ return 0;
+ }
+ chain = lock_chains + nr_lock_chains++;
+ chain->chain_key = chain_key;
+ chain->irq_context = hlock->irq_context;
+ /* Find the first held_lock of current chain */
+ hlock_next = hlock;
+ for (i = curr->lockdep_depth - 1; i >= 0; i--) {
+ hlock_curr = curr->held_locks + i;
+ if (hlock_curr->irq_context != hlock_next->irq_context)
+ break;
+ hlock_next = hlock;
+ }
+ i++;
+ chain->depth = curr->lockdep_depth + 1 - i;
+ cn = nr_chain_hlocks;
+ while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) {
+ n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth);
+ if (n == cn)
+ break;
+ cn = n;
+ }
+ if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
+ chain->base = cn;
+ for (j = 0; j < chain->depth - 1; j++, i++) {
+ int lock_id = curr->held_locks[i].class_idx - 1;
+ chain_hlocks[chain->base + j] = lock_id;
+ }
+ chain_hlocks[chain->base + j] = class - lock_classes;
+ }
+ list_add_tail_rcu(&chain->entry, hash_head);
+ debug_atomic_inc(&chain_lookup_misses);
+ inc_chains();
+
+ return 1;
+}
+
+static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
+ struct held_lock *hlock, int chain_head, u64 chain_key)
+{
+ /*
+ * Trylock needs to maintain the stack of held locks, but it
+ * does not add new dependencies, because trylock can be done
+ * in any order.
+ *
+ * We look up the chain_key and do the O(N^2) check and update of
+ * the dependencies only if this is a new dependency chain.
+ * (If lookup_chain_cache() returns with 1 it acquires
+ * graph_lock for us)
+ */
+ if (!hlock->trylock && (hlock->check == 2) &&
+ lookup_chain_cache(curr, hlock, chain_key)) {
+ /*
+ * Check whether last held lock:
+ *
+ * - is irq-safe, if this lock is irq-unsafe
+ * - is softirq-safe, if this lock is hardirq-unsafe
+ *
+ * And check whether the new lock's dependency graph
+ * could lead back to the previous lock.
+ *
+ * any of these scenarios could lead to a deadlock. If
+ * All validations
+ */
+ int ret = check_deadlock(curr, hlock, lock, hlock->read);
+
+ if (!ret)
+ return 0;
+ /*
+ * Mark recursive read, as we jump over it when
+ * building dependencies (just like we jump over
+ * trylock entries):
+ */
+ if (ret == 2)
+ hlock->read = 2;
+ /*
+ * Add dependency only if this lock is not the head
+ * of the chain, and if it's not a secondary read-lock:
+ */
+ if (!chain_head && ret != 2)
+ if (!check_prevs_add(curr, hlock))
+ return 0;
+ graph_unlock();
+ } else
+ /* after lookup_chain_cache(): */
+ if (unlikely(!debug_locks))
+ return 0;
+
+ return 1;
+}
#else
- nr_process_chains++;
-#endif
-
+static inline int validate_chain(struct task_struct *curr,
+ struct lockdep_map *lock, struct held_lock *hlock,
+ int chain_head, u64 chain_key)
+{
return 1;
}
#endif
hlock = curr->held_locks + i;
if (chain_key != hlock->prev_chain_key) {
debug_locks_off();
- printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n",
+ WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
curr->lockdep_depth, i,
(unsigned long long)chain_key,
(unsigned long long)hlock->prev_chain_key);
- WARN_ON(1);
return;
}
- id = hlock->class - lock_classes;
+ id = hlock->class_idx - 1;
if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
return;
}
if (chain_key != curr->curr_chain_key) {
debug_locks_off();
- printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n",
+ WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
curr->lockdep_depth, i,
(unsigned long long)chain_key,
(unsigned long long)curr->curr_chain_key);
- WARN_ON(1);
}
#endif
}
-#ifdef CONFIG_TRACE_IRQFLAGS
+static int
+print_usage_bug(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n=================================\n");
+ printk( "[ INFO: inconsistent lock state ]\n");
+ print_kernel_version();
+ printk( "---------------------------------\n");
+
+ printk("inconsistent {%s} -> {%s} usage.\n",
+ usage_str[prev_bit], usage_str[new_bit]);
+
+ printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
+ curr->comm, task_pid_nr(curr),
+ trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
+ trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
+ trace_hardirqs_enabled(curr),
+ trace_softirqs_enabled(curr));
+ print_lock(this);
+
+ printk("{%s} state was registered at:\n", usage_str[prev_bit]);
+ print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
+
+ print_irqtrace_events(curr);
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Print out an error if an invalid bit is set:
+ */
+static inline int
+valid_state(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+{
+ if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
+ return print_usage_bug(curr, this, bad_bit, new_bit);
+ return 1;
+}
+
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit);
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
/*
* print irq inversion bug:
*/
static int
-print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
+print_irq_inversion_bug(struct task_struct *curr,
+ struct lock_list *root, struct lock_list *other,
struct held_lock *this, int forwards,
const char *irqclass)
{
print_kernel_version();
printk( "---------------------------------------------------------\n");
printk("%s/%d just changed the state of lock:\n",
- curr->comm, curr->pid);
+ 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);
- print_lock_name(other);
+ printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
+ print_lock_name(other->class);
printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
printk("\nother info that might help us debug this:\n");
lockdep_print_held_locks(curr);
- printk("\nthe first lock's dependencies:\n");
- print_lock_dependencies(this->class, 0);
-
- printk("\nthe second lock's dependencies:\n");
- print_lock_dependencies(other, 0);
+ printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
+ if (!save_trace(&root->trace))
+ return 0;
+ print_shortest_lock_dependencies(other, root);
printk("\nstack backtrace:\n");
dump_stack();
enum lock_usage_bit bit, const char *irqclass)
{
int ret;
-
- find_usage_bit = bit;
- /* fills in <forwards_match> */
- ret = find_usage_forwards(this->class, 0);
- if (!ret || ret == 1)
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
+
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_forwards(&root, bit, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass);
+ return print_irq_inversion_bug(curr, &root, target_entry,
+ this, 1, irqclass);
}
/*
enum lock_usage_bit bit, const char *irqclass)
{
int ret;
-
- find_usage_bit = bit;
- /* fills in <backwards_match> */
- ret = find_usage_backwards(this->class, 0);
- if (!ret || ret == 1)
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
+
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_backwards(&root, bit, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
+ return print_irq_inversion_bug(curr, &root, target_entry,
+ this, 1, irqclass);
}
void print_irqtrace_events(struct task_struct *curr)
print_ip_sym(curr->softirq_disable_ip);
}
-#endif
-
-static int
-print_usage_bug(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+static int HARDIRQ_verbose(struct lock_class *class)
{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n=================================\n");
- printk( "[ INFO: inconsistent lock state ]\n");
- print_kernel_version();
- printk( "---------------------------------\n");
-
- printk("inconsistent {%s} -> {%s} usage.\n",
- usage_str[prev_bit], usage_str[new_bit]);
-
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
- curr->comm, curr->pid,
- trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
- trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
- trace_hardirqs_enabled(curr),
- trace_softirqs_enabled(curr));
- print_lock(this);
-
- printk("{%s} state was registered at:\n", usage_str[prev_bit]);
- print_stack_trace(this->class->usage_traces + prev_bit, 1);
-
- print_irqtrace_events(curr);
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
+#if HARDIRQ_VERBOSE
+ return class_filter(class);
+#endif
return 0;
}
-/*
- * Print out an error if an invalid bit is set:
- */
-static inline int
-valid_state(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+static int SOFTIRQ_verbose(struct lock_class *class)
{
- if (unlikely(this->class->usage_mask & (1 << bad_bit)))
- return print_usage_bug(curr, this, bad_bit, new_bit);
- return 1;
+#if SOFTIRQ_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
}
-#define STRICT_READ_CHECKS 1
-
-/*
- * Mark a lock with a usage bit, and validate the state transition:
- */
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
+static int RECLAIM_FS_verbose(struct lock_class *class)
{
- unsigned int new_mask = 1 << new_bit, ret = 1;
-
- /*
- * If already set then do not dirty the cacheline,
- * nor do any checks:
- */
- if (likely(this->class->usage_mask & new_mask))
- return 1;
-
- if (!graph_lock())
- return 0;
- /*
- * Make sure we didnt race:
- */
- if (unlikely(this->class->usage_mask & new_mask)) {
- graph_unlock();
- return 1;
- }
-
- this->class->usage_mask |= new_mask;
-
- if (!save_trace(this->class->usage_traces + new_bit))
- return 0;
-
- switch (new_bit) {
-#ifdef CONFIG_TRACE_IRQFLAGS
- case LOCK_USED_IN_HARDIRQ:
- if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
- return 0;
- if (!valid_state(curr, this, new_bit,
- LOCK_ENABLED_HARDIRQS_READ))
- 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(this->class))
- 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(this->class))
- 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(this->class))
- 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(this->class))
- 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(this->class))
- 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(this->class))
- 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(this->class))
- 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(this->class))
- ret = 2;
- break;
-#endif
- case LOCK_USED:
- /*
- * Add it to the global list of classes:
- */
- list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes);
- debug_atomic_dec(&nr_unused_locks);
- break;
- default:
- if (!debug_locks_off_graph_unlock())
- return 0;
- WARN_ON(1);
+#if RECLAIM_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+#define STRICT_READ_CHECKS 1
+
+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 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;
- }
- graph_unlock();
+ /*
+ * 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;
/*
- * We must printk outside of the graph_lock:
+ * Check for read in write conflicts
*/
- if (ret == 2) {
- printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
- print_lock(this);
- print_irqtrace_events(curr);
- dump_stack();
+ if (!read) {
+ if (!valid_state(curr, this, new_bit, excl_bit + 1))
+ return 0;
+
+ if (STRICT_READ_CHECKS &&
+ !usage(curr, this, excl_bit + 1,
+ state_name(new_bit + 1)))
+ return 0;
}
- return ret;
+ if (state_verbose(new_bit, hlock_class(this)))
+ return 2;
+
+ return 1;
}
-#ifdef CONFIG_TRACE_IRQFLAGS
+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;
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;
}
/*
* Hardirqs will be enabled:
*/
-void trace_hardirqs_on(void)
+void trace_hardirqs_on_caller(unsigned long ip)
{
struct task_struct *curr = current;
- unsigned long ip;
+
+ time_hardirqs_on(CALLER_ADDR0, ip);
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
}
/* we'll do an OFF -> ON transition: */
curr->hardirqs_enabled = 1;
- ip = (unsigned long) __builtin_return_address(0);
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return;
* 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
* 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;
curr->hardirq_enable_event = ++curr->irq_events;
debug_atomic_inc(&hardirqs_on_events);
}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+void trace_hardirqs_on(void)
+{
+ trace_hardirqs_on_caller(CALLER_ADDR0);
+}
EXPORT_SYMBOL(trace_hardirqs_on);
/*
* Hardirqs were disabled:
*/
-void trace_hardirqs_off(void)
+void trace_hardirqs_off_caller(unsigned long ip)
{
struct task_struct *curr = current;
+ time_hardirqs_off(CALLER_ADDR0, ip);
+
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
* We have done an ON -> OFF transition:
*/
curr->hardirqs_enabled = 0;
- curr->hardirq_disable_ip = _RET_IP_;
+ curr->hardirq_disable_ip = ip;
curr->hardirq_disable_event = ++curr->irq_events;
debug_atomic_inc(&hardirqs_off_events);
} else
debug_atomic_inc(&redundant_hardirqs_off);
}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+void trace_hardirqs_off(void)
+{
+ trace_hardirqs_off_caller(CALLER_ADDR0);
+}
EXPORT_SYMBOL(trace_hardirqs_off);
/*
}
/*
- * We'll do an OFF -> ON transition:
- */
- curr->softirqs_enabled = 1;
- curr->softirq_enable_ip = ip;
- curr->softirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(&softirqs_on_events);
- /*
- * We are going to turn softirqs on, so set the
- * usage bit for all held locks, if hardirqs are
- * enabled too:
+ * We'll do an OFF -> ON transition:
+ */
+ curr->softirqs_enabled = 1;
+ curr->softirq_enable_ip = ip;
+ curr->softirq_enable_event = ++curr->irq_events;
+ debug_atomic_inc(&softirqs_on_events);
+ /*
+ * We are going to turn softirqs on, so set the
+ * usage bit for all held locks, if hardirqs are
+ * enabled too:
+ */
+ if (curr->hardirqs_enabled)
+ mark_held_locks(curr, SOFTIRQ);
+}
+
+/*
+ * Softirqs were disabled:
+ */
+void trace_softirqs_off(unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(!debug_locks))
+ return;
+
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ if (curr->softirqs_enabled) {
+ /*
+ * We have done an ON -> OFF transition:
+ */
+ curr->softirqs_enabled = 0;
+ curr->softirq_disable_ip = ip;
+ curr->softirq_disable_event = ++curr->irq_events;
+ debug_atomic_inc(&softirqs_off_events);
+ DEBUG_LOCKS_WARN_ON(!softirq_count());
+ } else
+ 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)
+{
+ /*
+ * If non-trylock use in a hardirq or softirq context, then
+ * mark the lock as used in these contexts:
+ */
+ if (!hlock->trylock) {
+ if (hlock->read) {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_HARDIRQ_READ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_SOFTIRQ_READ))
+ return 0;
+ } else {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
+ return 0;
+ }
+ }
+ if (!hlock->hardirqs_off) {
+ if (hlock->read) {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQ_READ))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_SOFTIRQ_READ))
+ return 0;
+ } else {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQ))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ 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;
+ }
+ }
+
+ return 1;
+}
+
+static int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ unsigned int depth = curr->lockdep_depth;
+
+ /*
+ * Keep track of points where we cross into an interrupt context:
+ */
+ hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
+ curr->softirq_context;
+ if (depth) {
+ struct held_lock *prev_hlock;
+
+ prev_hlock = curr->held_locks + depth-1;
+ /*
+ * If we cross into another context, reset the
+ * hash key (this also prevents the checking and the
+ * adding of the dependency to 'prev'):
+ */
+ if (prev_hlock->irq_context != hlock->irq_context)
+ return 1;
+ }
+ return 0;
+}
+
+#else
+
+static inline
+int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ WARN_ON(1);
+ return 1;
+}
+
+static inline int mark_irqflags(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 1;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 0;
+}
+
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+}
+
+#endif
+
+/*
+ * Mark a lock with a usage bit, and validate the state transition:
+ */
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ unsigned int new_mask = 1 << new_bit, ret = 1;
+
+ /*
+ * If already set then do not dirty the cacheline,
+ * nor do any checks:
+ */
+ if (likely(hlock_class(this)->usage_mask & new_mask))
+ return 1;
+
+ if (!graph_lock())
+ return 0;
+ /*
+ * Make sure we didnt race:
+ */
+ if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
+ graph_unlock();
+ return 1;
+ }
+
+ hlock_class(this)->usage_mask |= new_mask;
+
+ if (!save_trace(hlock_class(this)->usage_traces + new_bit))
+ return 0;
+
+ switch (new_bit) {
+#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;
+ break;
+ case LOCK_USED:
+ debug_atomic_dec(&nr_unused_locks);
+ break;
+ default:
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+ WARN_ON(1);
+ return 0;
+ }
+
+ graph_unlock();
+
+ /*
+ * We must printk outside of the graph_lock:
*/
- if (curr->hardirqs_enabled)
- mark_held_locks(curr, 0);
-}
-
-/*
- * Softirqs were disabled:
- */
-void trace_softirqs_off(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
+ if (ret == 2) {
+ printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+ print_lock(this);
+ print_irqtrace_events(curr);
+ dump_stack();
+ }
- if (curr->softirqs_enabled) {
- /*
- * We have done an ON -> OFF transition:
- */
- curr->softirqs_enabled = 0;
- curr->softirq_disable_ip = ip;
- curr->softirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(&softirqs_off_events);
- DEBUG_LOCKS_WARN_ON(!softirq_count());
- } else
- debug_atomic_inc(&redundant_softirqs_off);
+ return ret;
}
-#endif
-
/*
* Initialize a lock instance's lock-class mapping info:
*/
void lockdep_init_map(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass)
{
- if (unlikely(!debug_locks))
+ lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+ lock->cpu = raw_smp_processor_id();
+#endif
+
+ if (DEBUG_LOCKS_WARN_ON(!name)) {
+ lock->name = "NULL";
return;
+ }
+
+ lock->name = name;
if (DEBUG_LOCKS_WARN_ON(!key))
return;
- if (DEBUG_LOCKS_WARN_ON(!name))
- return;
/*
* Sanity check, the lock-class key must be persistent:
*/
DEBUG_LOCKS_WARN_ON(1);
return;
}
- lock->name = name;
lock->key = key;
- lock->class_cache = NULL;
+
+ if (unlikely(!debug_locks))
+ return;
+
if (subclass)
register_lock_class(lock, subclass, 1);
}
-
EXPORT_SYMBOL_GPL(lockdep_init_map);
/*
*/
static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
int trylock, int read, int check, int hardirqs_off,
- unsigned long ip)
+ struct lockdep_map *nest_lock, unsigned long ip,
+ int references)
{
struct task_struct *curr = current;
struct lock_class *class = NULL;
struct held_lock *hlock;
unsigned int depth, id;
int chain_head = 0;
+ int class_idx;
u64 chain_key;
+ if (!prove_locking)
+ check = 1;
+
if (unlikely(!debug_locks))
return 0;
debug_locks_off();
printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return 0;
}
if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
return 0;
- hlock = curr->held_locks + depth;
+ class_idx = class - lock_classes + 1;
+
+ if (depth) {
+ hlock = curr->held_locks + depth - 1;
+ if (hlock->class_idx == class_idx && nest_lock) {
+ if (hlock->references)
+ hlock->references++;
+ else
+ hlock->references = 2;
+
+ return 1;
+ }
+ }
- hlock->class = class;
+ hlock = curr->held_locks + depth;
+ if (DEBUG_LOCKS_WARN_ON(!class))
+ return 0;
+ hlock->class_idx = class_idx;
hlock->acquire_ip = ip;
hlock->instance = lock;
+ hlock->nest_lock = nest_lock;
hlock->trylock = trylock;
hlock->read = read;
hlock->check = check;
- hlock->hardirqs_off = hardirqs_off;
-
- if (check != 2)
- goto out_calc_hash;
-#ifdef CONFIG_TRACE_IRQFLAGS
- /*
- * If non-trylock use in a hardirq or softirq context, then
- * mark the lock as used in these contexts:
- */
- if (!trylock) {
- if (read) {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_HARDIRQ_READ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_SOFTIRQ_READ))
- return 0;
- } else {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
- return 0;
- }
- }
- if (!hardirqs_off) {
- if (read) {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS_READ))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS_READ))
- return 0;
- } else {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS))
- return 0;
- }
- }
+ hlock->hardirqs_off = !!hardirqs_off;
+ hlock->references = references;
+#ifdef CONFIG_LOCK_STAT
+ hlock->waittime_stamp = 0;
+ hlock->holdtime_stamp = sched_clock();
#endif
+
+ if (check == 2 && !mark_irqflags(curr, hlock))
+ return 0;
+
/* mark it as used: */
if (!mark_lock(curr, hlock, LOCK_USED))
return 0;
-out_calc_hash:
+
/*
- * Calculate the chain hash: it's the combined has of all the
+ * Calculate the chain hash: it's the combined hash of all the
* lock keys along the dependency chain. We save the hash value
* at every step so that we can get the current hash easily
* after unlock. The chain hash is then used to cache dependency
}
hlock->prev_chain_key = chain_key;
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- /*
- * Keep track of points where we cross into an interrupt context:
- */
- hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
- curr->softirq_context;
- if (depth) {
- struct held_lock *prev_hlock;
-
- prev_hlock = curr->held_locks + depth-1;
- /*
- * If we cross into another context, reset the
- * hash key (this also prevents the checking and the
- * adding of the dependency to 'prev'):
- */
- if (prev_hlock->irq_context != hlock->irq_context) {
- chain_key = 0;
- chain_head = 1;
- }
+ if (separate_irq_context(curr, hlock)) {
+ chain_key = 0;
+ chain_head = 1;
}
-#endif
chain_key = iterate_chain_key(chain_key, id);
- curr->curr_chain_key = chain_key;
-
- /*
- * Trylock needs to maintain the stack of held locks, but it
- * does not add new dependencies, because trylock can be done
- * in any order.
- *
- * We look up the chain_key and do the O(N^2) check and update of
- * the dependencies only if this is a new dependency chain.
- * (If lookup_chain_cache() returns with 1 it acquires
- * graph_lock for us)
- */
- if (!trylock && (check == 2) && lookup_chain_cache(chain_key, class)) {
- /*
- * Check whether last held lock:
- *
- * - is irq-safe, if this lock is irq-unsafe
- * - is softirq-safe, if this lock is hardirq-unsafe
- *
- * And check whether the new lock's dependency graph
- * could lead back to the previous lock.
- *
- * any of these scenarios could lead to a deadlock. If
- * All validations
- */
- int ret = check_deadlock(curr, hlock, lock, read);
- if (!ret)
- return 0;
- /*
- * Mark recursive read, as we jump over it when
- * building dependencies (just like we jump over
- * trylock entries):
- */
- if (ret == 2)
- hlock->read = 2;
- /*
- * Add dependency only if this lock is not the head
- * of the chain, and if it's not a secondary read-lock:
- */
- if (!chain_head && ret != 2)
- if (!check_prevs_add(curr, hlock))
- return 0;
- graph_unlock();
- } else
- /* after lookup_chain_cache(): */
- if (unlikely(!debug_locks))
- return 0;
+ if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
+ return 0;
+ curr->curr_chain_key = chain_key;
curr->lockdep_depth++;
check_chain_key(curr);
#ifdef CONFIG_DEBUG_LOCKDEP
debug_locks_off();
printk("BUG: MAX_LOCK_DEPTH too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return 0;
}
if (debug_locks_silent)
return 0;
- printk("\n=====================================\n");
- printk( "[ BUG: bad unlock balance detected! ]\n");
- printk( "-------------------------------------\n");
- printk("%s/%d is trying to release lock (",
- curr->comm, curr->pid);
- print_lockdep_cache(lock);
- printk(") at:\n");
- print_ip_sym(ip);
- printk("but there are no more locks to release!\n");
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
+ printk("\n=====================================\n");
+ printk( "[ BUG: bad unlock balance detected! ]\n");
+ printk( "-------------------------------------\n");
+ printk("%s/%d is trying to release lock (",
+ curr->comm, task_pid_nr(curr));
+ print_lockdep_cache(lock);
+ printk(") at:\n");
+ print_ip_sym(ip);
+ printk("but there are no more locks to release!\n");
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Common debugging checks for both nested and non-nested unlock:
+ */
+static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
+ unsigned long ip)
+{
+ if (unlikely(!debug_locks))
+ return 0;
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+
+ if (curr->lockdep_depth <= 0)
+ return print_unlock_inbalance_bug(curr, lock, ip);
+
+ return 1;
+}
+
+static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
+{
+ if (hlock->instance == lock)
+ return 1;
+
+ if (hlock->references) {
+ struct lock_class *class = lock->class_cache;
+
+ if (!class)
+ class = look_up_lock_class(lock, 0);
+
+ if (DEBUG_LOCKS_WARN_ON(!class))
+ return 0;
+
+ if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
+ return 0;
+
+ if (hlock->class_idx == class - lock_classes + 1)
+ return 1;
+ }
+
+ return 0;
+}
+
+static int
+__lock_set_class(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, unsigned int subclass,
+ unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class *class;
+ unsigned int depth;
+ int i;
+
+ depth = curr->lockdep_depth;
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return 0;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (match_held_lock(hlock, lock))
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ return print_unlock_inbalance_bug(curr, lock, ip);
+
+found_it:
+ lockdep_init_map(lock, name, key, 0);
+ class = register_lock_class(lock, subclass, 0);
+ hlock->class_idx = class - lock_classes + 1;
- printk("\nstack backtrace:\n");
- dump_stack();
+ curr->lockdep_depth = i;
+ curr->curr_chain_key = hlock->prev_chain_key;
- return 0;
-}
+ for (; i < depth; i++) {
+ hlock = curr->held_locks + i;
+ if (!__lock_acquire(hlock->instance,
+ hlock_class(hlock)->subclass, hlock->trylock,
+ hlock->read, hlock->check, hlock->hardirqs_off,
+ hlock->nest_lock, hlock->acquire_ip,
+ hlock->references))
+ return 0;
+ }
-/*
- * Common debugging checks for both nested and non-nested unlock:
- */
-static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
-{
- if (unlikely(!debug_locks))
- return 0;
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
return 0;
-
- if (curr->lockdep_depth <= 0)
- return print_unlock_inbalance_bug(curr, lock, ip);
-
return 1;
}
*/
if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
break;
- if (hlock->instance == lock)
+ if (match_held_lock(hlock, lock))
goto found_it;
prev_hlock = hlock;
}
return print_unlock_inbalance_bug(curr, lock, ip);
found_it:
+ if (hlock->instance == lock)
+ lock_release_holdtime(hlock);
+
+ if (hlock->references) {
+ hlock->references--;
+ if (hlock->references) {
+ /*
+ * We had, and after removing one, still have
+ * references, the current lock stack is still
+ * valid. We're done!
+ */
+ return 1;
+ }
+ }
+
/*
* We have the right lock to unlock, 'hlock' points to it.
* Now we remove it from the stack, and add back the other
* entries (if any), recalculating the hash along the way:
*/
+
curr->lockdep_depth = i;
curr->curr_chain_key = hlock->prev_chain_key;
for (i++; i < depth; i++) {
hlock = curr->held_locks + i;
if (!__lock_acquire(hlock->instance,
- hlock->class->subclass, hlock->trylock,
+ hlock_class(hlock)->subclass, hlock->trylock,
hlock->read, hlock->check, hlock->hardirqs_off,
- hlock->acquire_ip))
+ hlock->nest_lock, hlock->acquire_ip,
+ hlock->references))
return 0;
}
/*
* Is the unlock non-nested:
*/
- if (hlock->instance != lock)
+ if (hlock->instance != lock || hlock->references)
return lock_release_non_nested(curr, lock, ip);
curr->lockdep_depth--;
curr->curr_chain_key = hlock->prev_chain_key;
+ lock_release_holdtime(hlock);
+
#ifdef CONFIG_DEBUG_LOCKDEP
hlock->prev_chain_key = 0;
- hlock->class = NULL;
+ hlock->class_idx = 0;
hlock->acquire_ip = 0;
hlock->irq_context = 0;
#endif
check_chain_key(curr);
}
+static int __lock_is_held(struct lockdep_map *lock)
+{
+ struct task_struct *curr = current;
+ int i;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ struct held_lock *hlock = curr->held_locks + i;
+
+ if (match_held_lock(hlock, lock))
+ return 1;
+ }
+
+ return 0;
+}
+
/*
* Check whether we follow the irq-flags state precisely:
*/
static void check_flags(unsigned long flags)
{
-#if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS)
+#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
+ defined(CONFIG_TRACE_IRQFLAGS)
if (!debug_locks)
return;
- if (irqs_disabled_flags(flags))
- DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled);
- else
- DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled);
+ if (irqs_disabled_flags(flags)) {
+ if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
+ printk("possible reason: unannotated irqs-off.\n");
+ }
+ } else {
+ if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
+ printk("possible reason: unannotated irqs-on.\n");
+ }
+ }
/*
* We dont accurately track softirq state in e.g.
#endif
}
+void lock_set_class(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, unsigned int subclass,
+ unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ current->lockdep_recursion = 1;
+ check_flags(flags);
+ if (__lock_set_class(lock, name, key, subclass, ip))
+ check_chain_key(current);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_set_class);
+
/*
* We are not always called with irqs disabled - do that here,
* and also avoid lockdep recursion:
*/
void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
- int trylock, int read, int check, unsigned long ip)
+ int trylock, int read, int check,
+ struct lockdep_map *nest_lock, unsigned long ip)
{
unsigned long flags;
+ trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
+
if (unlikely(current->lockdep_recursion))
return;
current->lockdep_recursion = 1;
__lock_acquire(lock, subclass, trylock, read, check,
- irqs_disabled_flags(flags), ip);
+ irqs_disabled_flags(flags), nest_lock, ip, 0);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
-
EXPORT_SYMBOL_GPL(lock_acquire);
-void lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+void lock_release(struct lockdep_map *lock, int nested,
+ unsigned long ip)
{
unsigned long flags;
+ trace_lock_release(lock, nested, ip);
+
if (unlikely(current->lockdep_recursion))
return;
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
-
EXPORT_SYMBOL_GPL(lock_release);
+int lock_is_held(struct lockdep_map *lock)
+{
+ unsigned long flags;
+ int ret = 0;
+
+ if (unlikely(current->lockdep_recursion))
+ return ret;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+
+ current->lockdep_recursion = 1;
+ ret = __lock_is_held(lock);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(lock_is_held);
+
+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,
+ unsigned long ip)
+{
+ if (!debug_locks_off())
+ return 0;
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n=================================\n");
+ printk( "[ BUG: bad contention detected! ]\n");
+ printk( "---------------------------------\n");
+ printk("%s/%d is trying to contend lock (",
+ curr->comm, task_pid_nr(curr));
+ print_lockdep_cache(lock);
+ printk(") at:\n");
+ print_ip_sym(ip);
+ printk("but there are no locks held!\n");
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static void
+__lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class_stats *stats;
+ unsigned int depth;
+ int i, contention_point, contending_point;
+
+ depth = curr->lockdep_depth;
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (match_held_lock(hlock, lock))
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, ip);
+ return;
+
+found_it:
+ if (hlock->instance != lock)
+ return;
+
+ hlock->waittime_stamp = sched_clock();
+
+ contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
+ contending_point = lock_point(hlock_class(hlock)->contending_point,
+ lock->ip);
+
+ stats = get_lock_stats(hlock_class(hlock));
+ if (contention_point < LOCKSTAT_POINTS)
+ stats->contention_point[contention_point]++;
+ if (contending_point < LOCKSTAT_POINTS)
+ stats->contending_point[contending_point]++;
+ if (lock->cpu != smp_processor_id())
+ stats->bounces[bounce_contended + !!hlock->read]++;
+ put_lock_stats(stats);
+}
+
+static void
+__lock_acquired(struct lockdep_map *lock, unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class_stats *stats;
+ unsigned int depth;
+ u64 now;
+ s64 waittime = 0;
+ int i, cpu;
+
+ depth = curr->lockdep_depth;
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (match_held_lock(hlock, lock))
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, _RET_IP_);
+ return;
+
+found_it:
+ if (hlock->instance != lock)
+ return;
+
+ cpu = smp_processor_id();
+ if (hlock->waittime_stamp) {
+ now = sched_clock();
+ waittime = now - hlock->waittime_stamp;
+ hlock->holdtime_stamp = now;
+ }
+
+ trace_lock_acquired(lock, ip, waittime);
+
+ stats = get_lock_stats(hlock_class(hlock));
+ if (waittime) {
+ if (hlock->read)
+ lock_time_inc(&stats->read_waittime, waittime);
+ else
+ lock_time_inc(&stats->write_waittime, waittime);
+ }
+ if (lock->cpu != cpu)
+ stats->bounces[bounce_acquired + !!hlock->read]++;
+ put_lock_stats(stats);
+
+ lock->cpu = cpu;
+ lock->ip = ip;
+}
+
+void lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+ unsigned long flags;
+
+ trace_lock_contended(lock, ip);
+
+ if (unlikely(!lock_stat))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ __lock_contended(lock, ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_contended);
+
+void lock_acquired(struct lockdep_map *lock, unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(!lock_stat))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ __lock_acquired(lock, ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_acquired);
+#endif
+
/*
* Used by the testsuite, sanitize the validator state
* after a simulated failure:
list_del_rcu(&class->hash_entry);
list_del_rcu(&class->lock_entry);
+ class->key = NULL;
}
-static inline int within(void *addr, void *start, unsigned long size)
+static inline int within(const void *addr, void *start, unsigned long size)
{
return addr >= start && addr < start + size;
}
struct list_head *head;
unsigned long flags;
int i;
+ int locked;
raw_local_irq_save(flags);
- graph_lock();
+ locked = graph_lock();
/*
* Unhash all classes that were created by this module:
head = classhash_table + i;
if (list_empty(head))
continue;
- list_for_each_entry_safe(class, next, head, hash_entry)
+ list_for_each_entry_safe(class, next, head, hash_entry) {
if (within(class->key, start, size))
zap_class(class);
+ else if (within(class->name, start, size))
+ zap_class(class);
+ }
}
- graph_unlock();
+ if (locked)
+ graph_unlock();
raw_local_irq_restore(flags);
}
struct list_head *head;
unsigned long flags;
int i, j;
+ int locked;
raw_local_irq_save(flags);
* Debug check: in the end all mapped classes should
* be gone.
*/
- graph_lock();
+ locked = graph_lock();
for (i = 0; i < CLASSHASH_SIZE; i++) {
head = classhash_table + i;
if (list_empty(head))
}
}
}
- graph_unlock();
+ if (locked)
+ graph_unlock();
out_restore:
raw_local_irq_restore(flags);
{
printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
- printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
+ printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
- printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
+ printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
sizeof(struct list_head) * CLASSHASH_SIZE +
sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
- sizeof(struct list_head) * CHAINHASH_SIZE) / 1024);
+ sizeof(struct list_head) * CHAINHASH_SIZE
+#ifdef CONFIG_PROVE_LOCKING
+ + sizeof(struct circular_queue)
+#endif
+ ) / 1024
+ );
printk(" per task-struct memory footprint: %lu bytes\n",
sizeof(struct held_lock) * MAX_LOCK_DEPTH);
#ifdef CONFIG_DEBUG_LOCKDEP
- if (lockdep_init_error)
- printk("WARNING: lockdep init error! Arch code didnt call lockdep_init() early enough?\n");
+ if (lockdep_init_error) {
+ printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
+ printk("Call stack leading to lockdep invocation was:\n");
+ print_stack_trace(&lockdep_init_trace, 0);
+ }
#endif
}
-static inline int in_range(const void *start, const void *addr, const void *end)
-{
- return addr >= start && addr <= end;
-}
-
static void
print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
const void *mem_to, struct held_lock *hlock)
printk( "[ BUG: held lock freed! ]\n");
printk( "-------------------------\n");
printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
- curr->comm, curr->pid, mem_from, mem_to-1);
+ curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
print_lock(hlock);
lockdep_print_held_locks(curr);
dump_stack();
}
+static inline int not_in_range(const void* mem_from, unsigned long mem_len,
+ const void* lock_from, unsigned long lock_len)
+{
+ return lock_from + lock_len <= mem_from ||
+ mem_from + mem_len <= lock_from;
+}
+
/*
* Called when kernel memory is freed (or unmapped), or if a lock
* is destroyed or reinitialized - this code checks whether there is
*/
void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
{
- const void *mem_to = mem_from + mem_len, *lock_from, *lock_to;
struct task_struct *curr = current;
struct held_lock *hlock;
unsigned long flags;
for (i = 0; i < curr->lockdep_depth; i++) {
hlock = curr->held_locks + i;
- lock_from = (void *)hlock->instance;
- lock_to = (void *)(hlock->instance + 1);
-
- if (!in_range(mem_from, lock_from, mem_to) &&
- !in_range(mem_from, lock_to, mem_to))
+ if (not_in_range(mem_from, mem_len, hlock->instance,
+ sizeof(*hlock->instance)))
continue;
- print_freed_lock_bug(curr, mem_from, mem_to, hlock);
+ print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
break;
}
local_irq_restore(flags);
printk( "[ BUG: lock held at task exit time! ]\n");
printk( "-------------------------------------\n");
printk("%s/%d is exiting with locks still held!\n",
- curr->comm, curr->pid);
+ curr->comm, task_pid_nr(curr));
lockdep_print_held_locks(curr);
printk("\nstack backtrace:\n");
}
printk(" ignoring it.\n");
unlock = 0;
+ } else {
+ if (count != 10)
+ printk(KERN_CONT " locked it.\n");
}
- if (count != 10)
- printk(" locked it.\n");
do_each_thread(g, p) {
+ /*
+ * It's not reliable to print a task's held locks
+ * if it's not sleeping (or if it's not the current
+ * task):
+ */
+ if (p->state == TASK_RUNNING && p != current)
+ continue;
if (p->lockdep_depth)
lockdep_print_held_locks(p);
if (!unlock)
if (unlock)
read_unlock(&tasklist_lock);
}
-
EXPORT_SYMBOL_GPL(debug_show_all_locks);
-void debug_show_held_locks(struct task_struct *task)
+/*
+ * Careful: only use this function if you are sure that
+ * the task cannot run in parallel!
+ */
+void __debug_show_held_locks(struct task_struct *task)
{
if (unlikely(!debug_locks)) {
printk("INFO: lockdep is turned off.\n");
}
lockdep_print_held_locks(task);
}
+EXPORT_SYMBOL_GPL(__debug_show_held_locks);
+void debug_show_held_locks(struct task_struct *task)
+{
+ __debug_show_held_locks(task);
+}
EXPORT_SYMBOL_GPL(debug_show_held_locks);
+
+void lockdep_sys_exit(void)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(curr->lockdep_depth)) {
+ if (!debug_locks_off())
+ return;
+ printk("\n================================================\n");
+ printk( "[ BUG: lock held when returning to user space! ]\n");
+ printk( "------------------------------------------------\n");
+ printk("%s/%d is leaving the kernel with locks still held!\n",
+ curr->comm, curr->pid);
+ lockdep_print_held_locks(curr);
+ }
+}