*
* 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/stacktrace.h>
#include <linux/debug_locks.h>
#include <linux/irqflags.h>
+#include <linux/utsname.h>
+#include <linux/hash.h>
+#include <linux/ftrace.h>
#include <asm/sections.h>
#include "lockdep_internals.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
+
/*
- * hash_lock: protects the lockdep hashes and class/list/hash allocators.
+ * lockdep_lock: protects the lockdep graph, the hashes and the
+ * class/list/hash allocators.
*
* This is one of the rare exceptions where it's justified
* to use a raw spinlock - we really dont want the spinlock
- * code to recurse back into the lockdep code.
+ * code to recurse back into the lockdep code...
*/
-static raw_spinlock_t hash_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
-static int lockdep_initialized;
+static int graph_lock(void)
+{
+ __raw_spin_lock(&lockdep_lock);
+ /*
+ * Make sure that if another CPU detected a bug while
+ * walking the graph we dont change it (while the other
+ * CPU is busy printing out stuff with the graph lock
+ * dropped already)
+ */
+ if (!debug_locks) {
+ __raw_spin_unlock(&lockdep_lock);
+ return 0;
+ }
+ /* prevent any recursions within lockdep from causing deadlocks */
+ current->lockdep_recursion++;
+ return 1;
+}
-unsigned long nr_list_entries;
-static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
+static inline int graph_unlock(void)
+{
+ 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;
+}
/*
- * Allocate a lockdep entry. (assumes hash_lock held, returns
- * with NULL on failure)
+ * Turn lock debugging off and return with 0 if it was off already,
+ * and also release the graph lock:
*/
-static struct lock_list *alloc_list_entry(void)
+static inline int debug_locks_off_graph_unlock(void)
{
- if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
- __raw_spin_unlock(&hash_lock);
- debug_locks_off();
- printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
- printk("turning off the locking correctness validator.\n");
- return NULL;
- }
- return list_entries + nr_list_entries++;
+ int ret = debug_locks_off();
+
+ __raw_spin_unlock(&lockdep_lock);
+
+ return ret;
}
+static int lockdep_initialized;
+
+unsigned long nr_list_entries;
+static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
+
/*
* 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;
-static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-
/*
* 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];
* unique.
*/
#define iterate_chain_key(key1, key2) \
- (((key1) << MAX_LOCKDEP_KEYS_BITS/2) ^ \
- ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS/2)) ^ \
+ (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
+ ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
(key2))
void lockdep_off(void)
{
current->lockdep_recursion++;
}
-
EXPORT_SYMBOL(lockdep_off);
void lockdep_on(void)
{
current->lockdep_recursion--;
}
-
EXPORT_SYMBOL(lockdep_on);
-int lockdep_internal(void)
-{
- return current->lockdep_recursion != 0;
-}
-
-EXPORT_SYMBOL(lockdep_internal);
-
/*
* Debugging switches:
*/
#define VERBOSE 0
-#ifdef VERBOSE
-# define VERY_VERBOSE 0
-#endif
+#define VERY_VERBOSE 0
#if VERBOSE
# define HARDIRQ_VERBOSE 1
!strcmp(class->name, "&struct->lockfield"))
return 1;
#endif
- /* Allow everything else. 0 would be filter everything else */
- return 1;
+ /* Filter everything else. 1 would be to allow everything else */
+ return 0;
}
#endif
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 hash_lock.
+ * addresses. Protected by the graph_lock.
*/
unsigned long nr_stack_trace_entries;
static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
trace->entries = stack_trace + nr_stack_trace_entries;
- save_stack_trace(trace, NULL, 0, 3);
+ trace->skip = 3;
+
+ save_stack_trace(trace);
trace->max_entries = trace->nr_entries;
nr_stack_trace_entries += trace->nr_entries;
- if (DEBUG_LOCKS_WARN_ON(nr_stack_trace_entries > MAX_STACK_TRACE_ENTRIES))
- return 0;
if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
- __raw_spin_unlock(&hash_lock);
- if (debug_locks_off()) {
- printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
- printk("turning off the locking correctness validator.\n");
- dump_stack();
- }
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+
return 0;
}
unsigned int max_lockdep_depth;
unsigned int max_recursion_depth;
+static unsigned int lockdep_dependency_gen_id;
+
+static bool lockdep_dependency_visit(struct lock_class *source,
+ unsigned int depth)
+{
+ if (!depth)
+ lockdep_dependency_gen_id++;
+ if (source->dep_gen_id == lockdep_dependency_gen_id)
+ return true;
+ source->dep_gen_id = lockdep_dependency_gen_id;
+ return false;
+}
+
#ifdef CONFIG_DEBUG_LOCKDEP
/*
* We cannot printk in early bootup code. Not even early_printk()
* 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:
const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
{
- unsigned long offs, size;
- char *modname;
-
- return kallsyms_lookup((unsigned long)key, &size, &offs, &modname, str);
+ return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
}
void
static void print_lock_name(struct lock_class *class)
{
- char str[128], c1, c2, c3, c4;
+ char str[KSYM_NAME_LEN], c1, c2, c3, c4;
const char *name;
get_usage_chars(class, &c1, &c2, &c3, &c4);
static void print_lockdep_cache(struct lockdep_map *lock)
{
const char *name;
- char str[128];
+ char str[KSYM_NAME_LEN];
name = lock->name;
if (!name)
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);
/*
* printk all lock dependencies starting at <entry>:
*/
-static void print_lock_dependencies(struct lock_class *class, int depth)
+static void __used
+print_lock_dependencies(struct lock_class *class, int depth)
{
struct lock_list *entry;
+ if (lockdep_dependency_visit(class, depth))
+ return;
+
if (DEBUG_LOCKS_WARN_ON(depth >= 20))
return;
print_lock_class_header(class, depth);
list_for_each_entry(entry, &class->locks_after, entry) {
- DEBUG_LOCKS_WARN_ON(!entry->class);
+ if (DEBUG_LOCKS_WARN_ON(!entry->class))
+ return;
+
print_lock_dependencies(entry->class, depth + 1);
printk("%*s ... acquired at:\n",depth,"");
}
}
+static void print_kernel_version(void)
+{
+ printk("%s %.*s\n", init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version);
+}
+
+static int very_verbose(struct lock_class *class)
+{
+#if VERY_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
/*
- * Add a new dependency to the head of the list:
+ * Is this the address of a static object:
*/
-static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
- struct list_head *head, unsigned long ip)
+static int static_obj(void *obj)
{
- struct lock_list *entry;
+ unsigned long start = (unsigned long) &_stext,
+ end = (unsigned long) &_end,
+ addr = (unsigned long) obj;
+#ifdef CONFIG_SMP
+ int i;
+#endif
+
/*
- * Lock not present yet - get a new dependency struct and
- * add it to the list:
+ * static variable?
*/
- entry = alloc_list_entry();
- if (!entry)
- return 0;
-
- entry->class = this;
- save_trace(&entry->trace);
+ if ((addr >= start) && (addr < end))
+ return 1;
+#ifdef CONFIG_SMP
/*
- * 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:
+ * percpu var?
*/
- list_add_tail_rcu(&entry->entry, head);
+ 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);
- return 1;
-}
+ if ((addr >= start) && (addr < end))
+ return 1;
+ }
+#endif
-/*
- * 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;
+ /*
+ * module var?
+ */
+ return is_module_address(addr);
+}
/*
- * Print a dependency chain entry (this is only done when a deadlock
- * has been detected):
+ * To make lock name printouts unique, we calculate a unique
+ * class->name_version generation counter:
*/
-static noinline int
-print_circular_bug_entry(struct lock_list *target, unsigned int depth)
+static int count_matching_names(struct lock_class *new_class)
{
- if (debug_locks_silent)
+ struct lock_class *class;
+ int count = 0;
+
+ if (!new_class->name)
return 0;
- printk("\n-> #%u", depth);
- print_lock_name(target->class);
- printk(":\n");
- print_stack_trace(&target->trace, 6);
- 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;
}
/*
- * When a circular dependency is detected, print the
- * header first:
+ * 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_header(struct lock_list *entry, unsigned int depth)
+static inline struct lock_class *
+look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
{
- struct task_struct *curr = current;
-
- __raw_spin_unlock(&hash_lock);
- debug_locks_off();
- if (debug_locks_silent)
- return 0;
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
- printk("\n=======================================================\n");
- printk( "[ INFO: possible circular locking dependency detected ]\n");
- printk( "-------------------------------------------------------\n");
+#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");
+ 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");
+ 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;
+}
+
+/*
+ * 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):
+ */
+static noinline int
+print_circular_bug_entry(struct lock_list *target, unsigned int depth)
+{
+ 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;
+}
+
+/*
+ * When a circular dependency is detected, print the
+ * header first:
+ */
+static noinline int
+print_circular_bug_header(struct lock_list *entry, unsigned int depth)
+{
+ struct task_struct *curr = current;
+
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n=======================================================\n");
+ printk( "[ INFO: possible circular locking dependency detected ]\n");
+ 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(check_source);
printk("\nbut task is already holding lock:\n");
print_lock(check_target);
if (debug_locks_silent)
return 0;
- this.class = check_source->class;
- save_trace(&this.trace);
+ this.class = hlock_class(check_source);
+ if (!save_trace(&this.trace))
+ return 0;
+
print_circular_bug_entry(&this, 0);
printk("\nother info that might help us debug this:\n\n");
return 0;
}
+#define RECURSION_LIMIT 40
+
static int noinline print_infinite_recursion_bug(void)
{
- __raw_spin_unlock(&hash_lock);
- DEBUG_LOCKS_WARN_ON(1);
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ WARN_ON(1);
return 0;
}
+unsigned long __lockdep_count_forward_deps(struct lock_class *class,
+ unsigned int depth)
+{
+ struct lock_list *entry;
+ unsigned long ret = 1;
+
+ if (lockdep_dependency_visit(class, depth))
+ return 0;
+
+ /*
+ * Recurse this class's dependency list:
+ */
+ list_for_each_entry(entry, &class->locks_after, entry)
+ ret += __lockdep_count_forward_deps(entry->class, depth + 1);
+
+ return ret;
+}
+
+unsigned long lockdep_count_forward_deps(struct lock_class *class)
+{
+ unsigned long ret, flags;
+
+ local_irq_save(flags);
+ __raw_spin_lock(&lockdep_lock);
+ ret = __lockdep_count_forward_deps(class, 0);
+ __raw_spin_unlock(&lockdep_lock);
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+unsigned long __lockdep_count_backward_deps(struct lock_class *class,
+ unsigned int depth)
+{
+ struct lock_list *entry;
+ unsigned long ret = 1;
+
+ if (lockdep_dependency_visit(class, depth))
+ return 0;
+ /*
+ * Recurse this class's dependency list:
+ */
+ list_for_each_entry(entry, &class->locks_before, entry)
+ ret += __lockdep_count_backward_deps(entry->class, depth + 1);
+
+ return ret;
+}
+
+unsigned long lockdep_count_backward_deps(struct lock_class *class)
+{
+ unsigned long ret, flags;
+
+ local_irq_save(flags);
+ __raw_spin_lock(&lockdep_lock);
+ ret = __lockdep_count_backward_deps(class, 0);
+ __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.
{
struct lock_list *entry;
+ if (lockdep_dependency_visit(source, depth))
+ return 1;
+
debug_atomic_inc(&nr_cyclic_check_recursions);
if (depth > max_recursion_depth)
max_recursion_depth = depth;
- if (depth >= 20)
+ 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)
+ if (entry->class == hlock_class(check_target))
return print_circular_bug_header(entry, depth+1);
debug_atomic_inc(&nr_cyclic_checks);
if (!check_noncircular(entry->class, depth+1))
return 1;
}
-static int very_verbose(struct lock_class *class)
-{
-#if VERY_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-#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
struct lock_list *entry;
int ret;
+ if (lockdep_dependency_visit(source, depth))
+ return 1;
+
if (depth > max_recursion_depth)
max_recursion_depth = depth;
- if (depth >= 20)
+ if (depth >= RECURSION_LIMIT)
return print_infinite_recursion_bug();
debug_atomic_inc(&nr_find_usage_forwards_checks);
struct lock_list *entry;
int ret;
+ if (lockdep_dependency_visit(source, depth))
+ return 1;
+
+ if (!__raw_spin_is_locked(&lockdep_lock))
+ return DEBUG_LOCKS_WARN_ON(1);
+
if (depth > max_recursion_depth)
max_recursion_depth = depth;
- if (depth >= 20)
+ if (depth >= RECURSION_LIMIT)
return print_infinite_recursion_bug();
debug_atomic_inc(&nr_find_usage_backwards_checks);
return 2;
}
+ if (!source && debug_locks_off_graph_unlock()) {
+ WARN_ON(1);
+ return 0;
+ }
+
/*
* Check this lock's dependency list:
*/
enum lock_usage_bit bit2,
const char *irqclass)
{
- __raw_spin_unlock(&hash_lock);
- debug_locks_off();
- if (debug_locks_silent)
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;
printk("\n======================================================\n");
printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
irqclass, irqclass);
+ 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",
find_usage_bit = bit_backwards;
/* fills in <backwards_match> */
- ret = find_usage_backwards(prev->class, 0);
+ ret = find_usage_backwards(hlock_class(prev), 0);
if (!ret || ret == 1)
return ret;
find_usage_bit = bit_forwards;
- ret = find_usage_forwards(next->class, 0);
+ ret = find_usage_forwards(hlock_class(next), 0);
if (!ret || ret == 1)
return ret;
/* ret == 2 */
bit_backwards, bit_forwards, irqclass);
}
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ /*
+ * 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>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
+ LOCK_ENABLED_SOFTIRQS, "soft"))
+ return 0;
+
+ 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
static int
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
{
- debug_locks_off();
- __raw_spin_unlock(&hash_lock);
- if (debug_locks_silent)
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;
printk("\n=============================================\n");
printk( "[ INFO: possible recursive locking detected ]\n");
+ 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;
* any of these scenarios could lead to a deadlock.
*
* Then if all the validations pass, we add the forwards and backwards
- * dependency.
- */
-static int
-check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
- struct lock_list *entry;
- int ret;
-
- /*
- * 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;
+ * dependency.
+ */
+static int
+check_prev_add(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next, int distance)
+{
+ struct lock_list *entry;
+ int ret;
/*
- * 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"))
+ check_source = next;
+ check_target = prev;
+ if (!(check_noncircular(hlock_class(next), 0)))
+ return print_circular_bug_tail();
+
+ 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);
+ 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(hlock_class(next), hlock_class(prev),
+ &hlock_class(next)->locks_before,
+ next->acquire_ip, distance);
if (!ret)
return 0;
- /*
- * Return value of 2 signals 'dependency already added',
- * in that case we dont have to add the backlink either.
- */
- if (ret == 2)
- return 2;
- ret = add_lock_to_list(next->class, prev->class,
- &next->class->locks_before, next->acquire_ip);
/*
* Debugging printouts:
*/
- if (verbose(prev->class) || verbose(next->class)) {
- __raw_spin_unlock(&hash_lock);
+ 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();
- __raw_spin_lock(&hash_lock);
+ return graph_lock();
}
return 1;
}
* to be a head:
*/
if (curr->held_locks[depth].irq_context !=
- curr->held_locks[depth-1].irq_context)
- goto out_bug;
-
- for (;;) {
- hlock = curr->held_locks + depth-1;
- /*
- * Only non-recursive-read entries get new dependencies
- * added:
- */
- if (hlock->read != 2) {
- check_prev_add(curr, hlock, next);
- /*
- * Stop after the first non-trylock entry,
- * as non-trylock entries have added their
- * own direct dependencies already, so this
- * lock is connected to them indirectly:
- */
- if (!hlock->trylock)
- break;
- }
- depth--;
- /*
- * End of lock-stack?
- */
- if (!depth)
- break;
- /*
- * Stop the search if we cross into another context:
- */
- if (curr->held_locks[depth].irq_context !=
- curr->held_locks[depth-1].irq_context)
- break;
- }
- return 1;
-out_bug:
- __raw_spin_unlock(&hash_lock);
- DEBUG_LOCKS_WARN_ON(1);
-
- return 0;
-}
-
-
-/*
- * 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_end + 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;
-}
-
-extern void __error_too_big_MAX_LOCKDEP_SUBCLASSES(void);
-
-/*
- * 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.
- */
- if (sizeof(struct lock_class_key) > sizeof(struct lock_class))
- __error_too_big_MAX_LOCKDEP_SUBCLASSES();
-
- 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;
-}
-
-/*
- * 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)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
-
- 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_spin_lock(&hash_lock);
- /*
- * 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) {
- __raw_spin_unlock(&hash_lock);
- debug_locks_off();
- 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);
+ curr->held_locks[depth-1].irq_context)
+ goto out_bug;
- if (verbose(class)) {
- __raw_spin_unlock(&hash_lock);
- printk("\nnew class %p: %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
- __raw_spin_lock(&hash_lock);
+ for (;;) {
+ int distance = curr->lockdep_depth - depth + 1;
+ hlock = curr->held_locks + depth-1;
+ /*
+ * Only non-recursive-read entries get new dependencies
+ * added:
+ */
+ if (hlock->read != 2) {
+ if (!check_prev_add(curr, hlock, next, distance))
+ return 0;
+ /*
+ * Stop after the first non-trylock entry,
+ * as non-trylock entries have added their
+ * own direct dependencies already, so this
+ * lock is connected to them indirectly:
+ */
+ if (!hlock->trylock)
+ break;
+ }
+ depth--;
+ /*
+ * End of lock-stack?
+ */
+ if (!depth)
+ break;
+ /*
+ * Stop the search if we cross into another context:
+ */
+ if (curr->held_locks[depth].irq_context !=
+ curr->held_locks[depth-1].irq_context)
+ break;
}
-out_unlock_set:
- __raw_spin_unlock(&hash_lock);
+ return 1;
+out_bug:
+ if (!debug_locks_off_graph_unlock())
+ return 0;
- if (!subclass)
- lock->class_cache = class;
+ WARN_ON(1);
+
+ return 0;
+}
- DEBUG_LOCKS_WARN_ON(class->subclass != subclass);
+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];
- return class;
+struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
+{
+ return lock_classes + chain_hlocks[chain->base + i];
}
/*
* Look up a dependency chain. If the key is not present yet then
- * add it and return 0 - in this case the new dependency chain is
- * validated. If the key is already hashed, return 1.
+ * 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)
+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;
- DEBUG_LOCKS_WARN_ON(!irqs_disabled());
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
/*
* We can walk it lock-free, because entries only get added
* to the hash:
if (chain->chain_key == chain_key) {
cache_hit:
debug_atomic_inc(&chain_lookup_hits);
- /*
- * In the debugging case, force redundant checking
- * by returning 1:
- */
-#ifdef CONFIG_DEBUG_LOCKDEP
- __raw_spin_lock(&hash_lock);
- return 1;
-#endif
+ if (very_verbose(class))
+ printk("\nhash chain already cached, key: "
+ "%016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key,
+ class->key, class->name);
return 0;
}
}
+ if (very_verbose(class))
+ printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key, class->key, class->name);
/*
* Allocate a new chain entry from the static array, and add
* it to the hash:
*/
- __raw_spin_lock(&hash_lock);
+ if (!graph_lock())
+ return 0;
/*
* We have to walk the chain again locked - to avoid duplicates:
*/
list_for_each_entry(chain, hash_head, entry) {
if (chain->chain_key == chain_key) {
- __raw_spin_unlock(&hash_lock);
+ graph_unlock();
goto cache_hit;
}
}
if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
- __raw_spin_unlock(&hash_lock);
- debug_locks_off();
+ 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;
+ 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);
-#ifdef CONFIG_TRACE_IRQFLAGS
- if (current->hardirq_context)
- nr_hardirq_chains++;
- else {
- if (current->softirq_context)
- nr_softirq_chains++;
- else
- nr_process_chains++;
- }
-#else
- nr_process_chains++;
-#endif
+ 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
+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
/*
* We are building curr_chain_key incrementally, so double-check
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;
- DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS);
+ id = hlock->class_idx - 1;
+ if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+ return;
+
if (prev_hlock && (prev_hlock->irq_context !=
hlock->irq_context))
chain_key = 0;
}
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:
struct held_lock *this, int forwards,
const char *irqclass)
{
- __raw_spin_unlock(&hash_lock);
- debug_locks_off();
- if (debug_locks_silent)
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;
printk("\n=========================================================\n");
printk( "[ INFO: possible irq lock inversion dependency detected ]\n");
+ 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);
lockdep_print_held_locks(curr);
printk("\nthe first lock's dependencies:\n");
- print_lock_dependencies(this->class, 0);
+ print_lock_dependencies(hlock_class(this), 0);
printk("\nthe second lock's dependencies:\n");
print_lock_dependencies(other, 0);
find_usage_bit = bit;
/* fills in <forwards_match> */
- ret = find_usage_forwards(this->class, 0);
+ ret = find_usage_forwards(hlock_class(this), 0);
if (!ret || ret == 1)
return ret;
find_usage_bit = bit;
/* fills in <backwards_match> */
- ret = find_usage_backwards(this->class, 0);
+ ret = find_usage_backwards(hlock_class(this), 0);
if (!ret || ret == 1)
return ret;
return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
}
-static inline void print_irqtrace_events(struct task_struct *curr)
+void print_irqtrace_events(struct task_struct *curr)
{
printk("irq event stamp: %u\n", curr->irq_events);
printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
print_ip_sym(curr->softirq_disable_ip);
}
-#else
-static inline void print_irqtrace_events(struct task_struct *curr)
+static int hardirq_verbose(struct lock_class *class)
{
-}
+#if HARDIRQ_VERBOSE
+ return class_filter(class);
#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)
-{
- __raw_spin_unlock(&hash_lock);
- debug_locks_off();
- if (debug_locks_silent)
- return 0;
-
- printk("\n=================================\n");
- printk( "[ INFO: inconsistent lock state ]\n");
- 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();
-
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, unsigned long ip)
+static int mark_lock_irq(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(this->class->usage_mask & new_mask))
- return 1;
-
- __raw_spin_lock(&hash_lock);
- /*
- * Make sure we didnt race:
- */
- if (unlikely(this->class->usage_mask & new_mask)) {
- __raw_spin_unlock(&hash_lock);
- return 1;
- }
-
- this->class->usage_mask |= new_mask;
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- if (new_bit == LOCK_ENABLED_HARDIRQS ||
- new_bit == LOCK_ENABLED_HARDIRQS_READ)
- ip = curr->hardirq_enable_ip;
- else if (new_bit == LOCK_ENABLED_SOFTIRQS ||
- new_bit == LOCK_ENABLED_SOFTIRQS_READ)
- ip = curr->softirq_enable_ip;
-#endif
- if (!save_trace(this->class->usage_traces + new_bit))
- return 0;
+ int ret = 1;
- switch (new_bit) {
-#ifdef CONFIG_TRACE_IRQFLAGS
+ switch(new_bit) {
case LOCK_USED_IN_HARDIRQ:
if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
return 0;
LOCK_ENABLED_HARDIRQS_READ, "hard-read"))
return 0;
#endif
- if (hardirq_verbose(this->class))
+ if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_USED_IN_SOFTIRQ:
LOCK_ENABLED_SOFTIRQS_READ, "soft-read"))
return 0;
#endif
- if (softirq_verbose(this->class))
+ if (softirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_USED_IN_HARDIRQ_READ:
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_HARDIRQS, "hard"))
return 0;
- if (hardirq_verbose(this->class))
+ if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_USED_IN_SOFTIRQ_READ:
if (!check_usage_forwards(curr, this,
LOCK_ENABLED_SOFTIRQS, "soft"))
return 0;
- if (softirq_verbose(this->class))
+ if (softirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_HARDIRQS:
LOCK_USED_IN_HARDIRQ_READ, "hard-read"))
return 0;
#endif
- if (hardirq_verbose(this->class))
+ if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_SOFTIRQS:
LOCK_USED_IN_SOFTIRQ_READ, "soft-read"))
return 0;
#endif
- if (softirq_verbose(this->class))
+ if (softirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_HARDIRQS_READ:
LOCK_USED_IN_HARDIRQ, "hard"))
return 0;
#endif
- if (hardirq_verbose(this->class))
+ if (hardirq_verbose(hlock_class(this)))
ret = 2;
break;
case LOCK_ENABLED_SOFTIRQS_READ:
*/
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);
+ return 0;
+#endif
+ if (softirq_verbose(hlock_class(this)))
+ ret = 2;
break;
default:
- debug_locks_off();
WARN_ON(1);
- return 0;
- }
-
- __raw_spin_unlock(&hash_lock);
-
- /*
- * We must printk outside of the hash_lock:
- */
- if (ret == 2) {
- printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
- print_lock(this);
- print_irqtrace_events(curr);
- dump_stack();
+ break;
}
return ret;
}
-#ifdef CONFIG_TRACE_IRQFLAGS
/*
* Mark all held locks with a usage bit:
*/
static int
-mark_held_locks(struct task_struct *curr, int hardirq, unsigned long ip)
+mark_held_locks(struct task_struct *curr, int hardirq)
{
enum lock_usage_bit usage_bit;
struct held_lock *hlock;
else
usage_bit = LOCK_ENABLED_SOFTIRQS;
}
- if (!mark_lock(curr, hlock, usage_bit, ip))
+ 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, ip))
+ if (!mark_held_locks(curr, 1))
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, ip))
+ if (!mark_held_locks(curr, 0))
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);
/*
* enabled too:
*/
if (curr->hardirqs_enabled)
- mark_held_locks(curr, 0, ip);
+ mark_held_locks(curr, 0);
}
/*
debug_atomic_inc(&redundant_softirqs_off);
}
+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_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;
+ }
+ }
+
+ 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;
+}
+
#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) {
+ case LOCK_USED_IN_HARDIRQ:
+ case LOCK_USED_IN_SOFTIRQ:
+ case LOCK_USED_IN_HARDIRQ_READ:
+ case LOCK_USED_IN_SOFTIRQ_READ:
+ case LOCK_ENABLED_HARDIRQS:
+ case LOCK_ENABLED_SOFTIRQS:
+ case LOCK_ENABLED_HARDIRQS_READ:
+ case LOCK_ENABLED_SOFTIRQS_READ:
+ 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 (ret == 2) {
+ printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+ print_lock(this);
+ print_irqtrace_events(curr);
+ dump_stack();
+ }
+
+ return ret;
+}
+
+/*
* 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)
+ struct lock_class_key *key, int subclass)
{
if (unlikely(!debug_locks))
return;
lock->name = name;
lock->key = key;
lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+ lock->cpu = raw_smp_processor_id();
+#endif
+ 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)
{
struct task_struct *curr = current;
struct lock_class *class = NULL;
int chain_head = 0;
u64 chain_key;
+ if (!prove_locking)
+ check = 1;
+
if (unlikely(!debug_locks))
return 0;
* Not cached yet or subclass?
*/
if (unlikely(!class)) {
- class = register_lock_class(lock, subclass);
+ class = register_lock_class(lock, subclass, 0);
if (!class)
return 0;
}
return 0;
hlock = curr->held_locks + depth;
-
- hlock->class = class;
+ if (DEBUG_LOCKS_WARN_ON(!class))
+ return 0;
+ hlock->class_idx = class - lock_classes + 1;
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, ip))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_SOFTIRQ_READ, ip))
- return 0;
- } else {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ, ip))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ, ip))
- return 0;
- }
- }
- if (!hardirqs_off) {
- if (read) {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS_READ, ip))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS_READ, ip))
- return 0;
- } else {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS, ip))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS, ip))
- return 0;
- }
- }
+ hlock->hardirqs_off = !!hardirqs_off;
+#ifdef CONFIG_LOCK_STAT
+ hlock->waittime_stamp = 0;
+ hlock->holdtime_stamp = sched_clock();
#endif
- /* mark it as used: */
- if (!mark_lock(curr, hlock, LOCK_USED, ip))
- return 0;
-out_calc_hash:
- /*
- * Calculate the chain hash: it's the combined has 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
- * results.
- *
- * The 'key ID' is what is the most compact key value to drive
- * the hash, not class->key.
- */
- id = class - lock_classes;
- if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
- return 0;
-
- chain_key = curr->curr_chain_key;
- if (!depth) {
- if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
- return 0;
- chain_head = 1;
- }
-
- 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;
+ if (check == 2 && !mark_irqflags(curr, hlock))
+ return 0;
- 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;
- }
- }
-#endif
- chain_key = iterate_chain_key(chain_key, id);
- curr->curr_chain_key = chain_key;
+ /* mark it as used: */
+ if (!mark_lock(curr, hlock, LOCK_USED))
+ return 0;
- /*
- * 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
- * hash_lock for us)
- */
- if (!trylock && (check == 2) && lookup_chain_cache(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, read);
+ /*
+ * 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
+ * results.
+ *
+ * The 'key ID' is what is the most compact key value to drive
+ * the hash, not class->key.
+ */
+ id = class - lock_classes;
+ if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+ return 0;
- if (!ret)
+ chain_key = curr->curr_chain_key;
+ if (!depth) {
+ if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
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;
- __raw_spin_unlock(&hash_lock);
+ chain_head = 1;
+ }
+
+ hlock->prev_chain_key = chain_key;
+ if (separate_irq_context(curr, hlock)) {
+ chain_key = 0;
+ chain_head = 1;
}
+ chain_key = iterate_chain_key(chain_key, id);
+
+ 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
+ if (unlikely(!debug_locks))
+ return 0;
+#endif
if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
debug_locks_off();
printk("BUG: MAX_LOCK_DEPTH too low!\n");
printk("turning off the locking correctness validator.\n");
return 0;
}
+
if (unlikely(curr->lockdep_depth > max_lockdep_depth))
max_lockdep_depth = curr->lockdep_depth;
printk( "[ BUG: bad unlock balance detected! ]\n");
printk( "-------------------------------------\n");
printk("%s/%d is trying to release lock (",
- curr->comm, curr->pid);
+ curr->comm, task_pid_nr(curr));
print_lockdep_cache(lock);
printk(") at:\n");
print_ip_sym(ip);
return 1;
}
+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 (hlock->instance == 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;
+
+ curr->lockdep_depth = i;
+ curr->curr_chain_key = hlock->prev_chain_key;
+
+ 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))
+ return 0;
+ }
+
+ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
+ return 0;
+ return 1;
+}
+
/*
* Remove the lock to the list of currently held locks in a
* potentially non-nested (out of order) manner. This is a
return print_unlock_inbalance_bug(curr, lock, ip);
found_it:
+ lock_release_holdtime(hlock);
+
/*
* We have the right lock to unlock, 'hlock' points to it.
* Now we remove it from the stack, and add back the other
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))
return 0;
}
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
*/
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;
current->lockdep_recursion = 1;
__lock_acquire(lock, subclass, trylock, read, check,
- irqs_disabled_flags(flags), ip);
+ irqs_disabled_flags(flags), nest_lock, ip);
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;
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
-
EXPORT_SYMBOL_GPL(lock_release);
+#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 (hlock->instance == lock)
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, ip);
+ return;
+
+found_it:
+ 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 (hlock->instance == lock)
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, _RET_IP_);
+ return;
+
+found_it:
+ cpu = smp_processor_id();
+ if (hlock->waittime_stamp) {
+ now = sched_clock();
+ waittime = now - hlock->waittime_stamp;
+ hlock->holdtime_stamp = now;
+ }
+
+ 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;
+
+ 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:
void lockdep_reset(void)
{
unsigned long flags;
+ int i;
raw_local_irq_save(flags);
current->curr_chain_key = 0;
nr_softirq_chains = 0;
nr_process_chains = 0;
debug_locks = 1;
+ for (i = 0; i < CHAINHASH_SIZE; i++)
+ INIT_LIST_HEAD(chainhash_table + i);
raw_local_irq_restore(flags);
}
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);
- __raw_spin_lock(&hash_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);
+ }
}
- __raw_spin_unlock(&hash_lock);
+ 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.
*/
- __raw_spin_lock(&hash_lock);
+ locked = graph_lock();
for (i = 0; i < CLASSHASH_SIZE; i++) {
head = classhash_table + i;
if (list_empty(head))
continue;
list_for_each_entry_safe(class, next, head, hash_entry) {
if (unlikely(class == lock->class_cache)) {
- __raw_spin_unlock(&hash_lock);
- DEBUG_LOCKS_WARN_ON(1);
+ if (debug_locks_off_graph_unlock())
+ WARN_ON(1);
goto out_restore;
}
}
}
- __raw_spin_unlock(&hash_lock);
+ if (locked)
+ graph_unlock();
out_restore:
raw_local_irq_restore(flags);
}
-void __init lockdep_init(void)
+void lockdep_init(void)
{
int i;
{
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 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);
}
+EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
static void print_held_locks_bug(struct task_struct *curr)
{
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");
int count = 10;
int unlock = 1;
+ if (unlikely(!debug_locks)) {
+ printk("INFO: lockdep is turned off.\n");
+ return;
+ }
printk("\nShowing all locks held in the system:\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");
+ return;
+ }
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);
+ }
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff