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authorPeter Zijlstra <peterz@infradead.org>2013-10-31 18:14:17 +0100
committerIngo Molnar <mingo@kernel.org>2013-11-06 07:55:08 +0100
commit8eddac3f103736163f49255bcb109edadea167f6 (patch)
treecd3161b76bb7a7e2614817d0ba66446676e6b677 /kernel/lockdep.c
parent01768b42dc97a67b4fb33a2535c49fc1969880df (diff)
downloadlinux-8eddac3f103736163f49255bcb109edadea167f6.tar.bz2
locking: Move the lockdep code to kernel/locking/
Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-wl7s3tta5isufzfguc23et06@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/lockdep.c')
-rw-r--r--kernel/lockdep.c4257
1 files changed, 0 insertions, 4257 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
deleted file mode 100644
index 4e8e14c34e42..000000000000
--- a/kernel/lockdep.c
+++ /dev/null
@@ -1,4257 +0,0 @@
-/*
- * kernel/lockdep.c
- *
- * Runtime locking correctness validator
- *
- * Started by Ingo Molnar:
- *
- * 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:
- *
- * - lock inversion scenarios
- * - circular lock dependencies
- * - hardirq/softirq safe/unsafe locking bugs
- *
- * Bugs are reported even if the current locking scenario does not cause
- * any deadlock at this point.
- *
- * I.e. if anytime in the past two locks were taken in a different order,
- * even if it happened for another task, even if those were different
- * locks (but of the same class as this lock), this code will detect it.
- *
- * 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/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/interrupt.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 <linux/stringify.h>
-#include <linux/bitops.h>
-#include <linux/gfp.h>
-#include <linux/kmemcheck.h>
-
-#include <asm/sections.h>
-
-#include "lockdep_internals.h"
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/lock.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.
- *
- * 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...
- */
-static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
-
-static int graph_lock(void)
-{
- arch_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) {
- arch_spin_unlock(&lockdep_lock);
- return 0;
- }
- /* prevent any recursions within lockdep from causing deadlocks */
- current->lockdep_recursion++;
- return 1;
-}
-
-static inline int graph_unlock(void)
-{
- if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) {
- /*
- * The lockdep graph lock isn't locked while we expect it to
- * be, we're confused now, bye!
- */
- return DEBUG_LOCKS_WARN_ON(1);
- }
-
- current->lockdep_recursion--;
- arch_spin_unlock(&lockdep_lock);
- return 0;
-}
-
-/*
- * Turn lock debugging off and return with 0 if it was off already,
- * and also release the graph lock:
- */
-static inline int debug_locks_off_graph_unlock(void)
-{
- int ret = debug_locks_off();
-
- arch_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.
- *
- * Mutex key structs only get allocated, once during bootup, and never
- * get freed - this significantly simplifies the debugging code.
- */
-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) {
- /*
- * Someone passed in garbage, we give up.
- */
- 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],
- cpu_lock_stats);
-
-static inline u64 lockstat_clock(void)
-{
- return local_clock();
-}
-
-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, u64 time)
-{
- if (time > lt->max)
- lt->max = time;
-
- if (time < lt->min || !lt->nr)
- lt->min = time;
-
- lt->total += time;
- lt->nr++;
-}
-
-static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
-{
- if (!src->nr)
- return;
-
- if (src->max > dst->max)
- dst->max = src->max;
-
- if (src->min < dst->min || !dst->nr)
- dst->min = src->min;
-
- 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(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(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(cpu_lock_stats)[class - lock_classes];
-}
-
-static void put_lock_stats(struct lock_class_stats *stats)
-{
- put_cpu_var(cpu_lock_stats);
-}
-
-static void lock_release_holdtime(struct held_lock *hlock)
-{
- struct lock_class_stats *stats;
- u64 holdtime;
-
- if (!lock_stat)
- return;
-
- holdtime = lockstat_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
- * spinlock lock held.
- */
-LIST_HEAD(all_lock_classes);
-
-/*
- * The lockdep classes are in a hash-table as well, for fast lookup:
- */
-#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
-#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
-#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];
-
-/*
- * 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 __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
-#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
-
-static struct list_head chainhash_table[CHAINHASH_SIZE];
-
-/*
- * The hash key of the lock dependency chains is a hash itself too:
- * it's a hash of all locks taken up to that lock, including that lock.
- * It's a 64-bit hash, because it's important for the keys to be
- * unique.
- */
-#define iterate_chain_key(key1, key2) \
- (((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);
-
-/*
- * Debugging switches:
- */
-
-#define VERBOSE 0
-#define VERY_VERBOSE 0
-
-#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 || RECLAIM_VERBOSE
-/*
- * Quick filtering for interesting events:
- */
-static int class_filter(struct lock_class *class)
-{
-#if 0
- /* Example */
- if (class->name_version == 1 &&
- !strcmp(class->name, "lockname"))
- return 1;
- if (class->name_version == 1 &&
- !strcmp(class->name, "&struct->lockfield"))
- return 1;
-#endif
- /* Filter everything else. 1 would be to allow everything else */
- return 0;
-}
-#endif
-
-static int verbose(struct lock_class *class)
-{
-#if VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the graph_lock.
- */
-unsigned long nr_stack_trace_entries;
-static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
-
-static void print_lockdep_off(const char *bug_msg)
-{
- printk(KERN_DEBUG "%s\n", bug_msg);
- printk(KERN_DEBUG "turning off the locking correctness validator.\n");
- printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
-}
-
-static int save_trace(struct stack_trace *trace)
-{
- trace->nr_entries = 0;
- trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
- trace->entries = stack_trace + nr_stack_trace_entries;
-
- trace->skip = 3;
-
- 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->nr_entries != 0 &&
- 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-1) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
- dump_stack();
-
- return 0;
- }
-
- return 1;
-}
-
-unsigned int nr_hardirq_chains;
-unsigned int nr_softirq_chains;
-unsigned int nr_process_chains;
-unsigned int max_lockdep_depth;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-/*
- * We cannot printk in early bootup code. Not even early_printk()
- * might work. So we mark any initialization errors and printk
- * about it later on, in lockdep_info().
- */
-static int lockdep_init_error;
-static const char *lock_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:
- */
-DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
-#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[] =
-{
-#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);
-}
-
-static inline unsigned long lock_flag(enum lock_usage_bit bit)
-{
- return 1UL << bit;
-}
-
-static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
-{
- char c = '.';
-
- 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 = '?';
- }
-
- 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];
- const char *name;
-
- name = class->name;
- if (!name) {
- name = __get_key_name(class->key, str);
- printk("%s", name);
- } else {
- printk("%s", name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- if (class->subclass)
- printk("/%d", class->subclass);
- }
-}
-
-static void print_lock_name(struct lock_class *class)
-{
- char usage[LOCK_USAGE_CHARS];
-
- get_usage_chars(class, usage);
-
- printk(" (");
- __print_lock_name(class);
- printk("){%s}", usage);
-}
-
-static void print_lockdep_cache(struct lockdep_map *lock)
-{
- const char *name;
- char str[KSYM_NAME_LEN];
-
- name = lock->name;
- if (!name)
- name = __get_key_name(lock->key->subkeys, str);
-
- printk("%s", name);
-}
-
-static void print_lock(struct held_lock *hlock)
-{
- print_lock_name(hlock_class(hlock));
- printk(", at: ");
- print_ip_sym(hlock->acquire_ip);
-}
-
-static void lockdep_print_held_locks(struct task_struct *curr)
-{
- int i, depth = curr->lockdep_depth;
-
- if (!depth) {
- 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, task_pid_nr(curr));
-
- for (i = 0; i < depth; i++) {
- printk(" #%d: ", i);
- print_lock(curr->held_locks + i);
- }
-}
-
-static void print_kernel_ident(void)
-{
- printk("%s %.*s %s\n", init_utsname()->release,
- (int)strcspn(init_utsname()->version, " "),
- init_utsname()->version,
- print_tainted());
-}
-
-static int very_verbose(struct lock_class *class)
-{
-#if VERY_VERBOSE
- return class_filter(class);
-#endif
- 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;
-
- /*
- * static variable?
- */
- if ((addr >= start) && (addr < end))
- return 1;
-
- if (arch_is_kernel_data(addr))
- return 1;
-
- /*
- * in-kernel percpu var?
- */
- if (is_kernel_percpu_address(addr))
- return 1;
-
- /*
- * module static or percpu var?
- */
- return is_module_address(addr) || is_module_percpu_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;
- lock_init_error = lock->name;
- save_stack_trace(&lockdep_init_trace);
- }
-#endif
-
- if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
- debug_locks_off();
- printk(KERN_ERR
- "BUG: looking up invalid subclass: %u\n", subclass);
- printk(KERN_ERR
- "turning off the locking correctness validator.\n");
- dump_stack();
- return NULL;
- }
-
- /*
- * 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) {
- /*
- * Huh! same key, different name? Did someone trample
- * on some memory? We're most confused.
- */
- 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))
- goto out_set_class_cache;
-
- /*
- * 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);
-
- print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
- 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);
-
-out_set_class_cache:
- if (!subclass || force)
- lock->class_cache[0] = class;
- else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
- lock->class_cache[subclass] = class;
-
- /*
- * Hash collision, did we smoke some? We found a class with a matching
- * hash but the subclass -- which is hashed in -- didn't match.
- */
- 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;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
- 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 stack_trace *trace)
-{
- 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;
-
- entry->class = this;
- entry->distance = distance;
- entry->trace = *trace;
- /*
- * 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;
-}
-
-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); /* Out-of-bounds, input fail */
- 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); /* Out-of-bounds, input fail */
- 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)
-{
- 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;
-}
-
-static void
-print_circular_lock_scenario(struct held_lock *src,
- struct held_lock *tgt,
- struct lock_list *prt)
-{
- struct lock_class *source = hlock_class(src);
- struct lock_class *target = hlock_class(tgt);
- struct lock_class *parent = prt->class;
-
- /*
- * A direct locking problem where unsafe_class lock is taken
- * directly by safe_class lock, then all we need to show
- * is the deadlock scenario, as it is obvious that the
- * unsafe lock is taken under the safe lock.
- *
- * But if there is a chain instead, where the safe lock takes
- * an intermediate lock (middle_class) where this lock is
- * not the same as the safe lock, then the lock chain is
- * used to describe the problem. Otherwise we would need
- * to show a different CPU case for each link in the chain
- * from the safe_class lock to the unsafe_class lock.
- */
- if (parent != source) {
- printk("Chain exists of:\n ");
- __print_lock_name(source);
- printk(" --> ");
- __print_lock_name(parent);
- printk(" --> ");
- __print_lock_name(target);
- printk("\n\n");
- }
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(parent);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(source);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
-}
-
-/*
- * 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 held_lock *check_src,
- struct held_lock *check_tgt)
-{
- struct task_struct *curr = current;
-
- if (debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("======================================================\n");
- printk("[ INFO: possible circular locking dependency detected ]\n");
- print_kernel_ident();
- printk("-------------------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(check_src);
- printk("\nbut task is already holding lock:\n");
- 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");
-
- print_circular_bug_entry(entry, depth);
-
- return 0;
-}
-
-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 *parent;
- struct lock_list *first_parent;
- int depth;
-
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- if (!save_trace(&this->trace))
- return 0;
-
- depth = get_lock_depth(target);
-
- print_circular_bug_header(target, depth, check_src, check_tgt);
-
- parent = get_lock_parent(target);
- first_parent = parent;
-
- while (parent) {
- print_circular_bug_entry(parent, --depth);
- parent = get_lock_parent(parent);
- }
-
- printk("\nother info that might help us debug this:\n\n");
- print_circular_lock_scenario(check_src, check_tgt,
- first_parent);
-
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static noinline int print_bfs_bug(int ret)
-{
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- /*
- * Breadth-first-search failed, graph got corrupted?
- */
- 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);
- arch_spin_lock(&lockdep_lock);
- ret = __lockdep_count_forward_deps(&this);
- arch_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);
- arch_spin_lock(&lockdep_lock);
- ret = __lockdep_count_backward_deps(&this);
- arch_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_list *root, struct lock_class *target,
- struct lock_list **target_entry)
-{
- int result;
-
- debug_atomic_inc(nr_cyclic_checks);
-
- result = __bfs_forwards(root, target, class_equal, target_entry);
-
- return result;
-}
-
-#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 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 @root->class that matches @bit.
- *
- * Return 0 if such a node exists in the subgraph, and put that node
- * into *@target_entry.
- *
- * Return 1 otherwise and keep *@target_entry unchanged.
- * Return <0 on error.
- */
-static int
-find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
- struct lock_list **target_entry)
-{
- int result;
-
- debug_atomic_inc(nr_find_usage_forwards_checks);
-
- result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
-
- return result;
-}
-
-/*
- * Find a node in the backwards-direction dependency sub-graph starting
- * at @root->class that matches @bit.
- *
- * Return 0 if such a node exists in the subgraph, and put that node
- * into *@target_entry.
- *
- * Return 1 otherwise and keep *@target_entry unchanged.
- * Return <0 on error.
- */
-static int
-find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
- struct lock_list **target_entry)
-{
- int result;
-
- debug_atomic_inc(nr_find_usage_backwards_checks);
-
- result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
-
- return result;
-}
-
-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);
- }
- }
- 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 path found in chain graph\n", __func__);
- break;
- }
-
- entry = get_lock_parent(entry);
- depth--;
- } while (entry && (depth >= 0));
-
- return;
-}
-
-static void
-print_irq_lock_scenario(struct lock_list *safe_entry,
- struct lock_list *unsafe_entry,
- struct lock_class *prev_class,
- struct lock_class *next_class)
-{
- struct lock_class *safe_class = safe_entry->class;
- struct lock_class *unsafe_class = unsafe_entry->class;
- struct lock_class *middle_class = prev_class;
-
- if (middle_class == safe_class)
- middle_class = next_class;
-
- /*
- * A direct locking problem where unsafe_class lock is taken
- * directly by safe_class lock, then all we need to show
- * is the deadlock scenario, as it is obvious that the
- * unsafe lock is taken under the safe lock.
- *
- * But if there is a chain instead, where the safe lock takes
- * an intermediate lock (middle_class) where this lock is
- * not the same as the safe lock, then the lock chain is
- * used to describe the problem. Otherwise we would need
- * to show a different CPU case for each link in the chain
- * from the safe_class lock to the unsafe_class lock.
- */
- if (middle_class != unsafe_class) {
- printk("Chain exists of:\n ");
- __print_lock_name(safe_class);
- printk(" --> ");
- __print_lock_name(middle_class);
- printk(" --> ");
- __print_lock_name(unsafe_class);
- printk("\n\n");
- }
-
- printk(" Possible interrupt unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(unsafe_class);
- printk(");\n");
- printk(" local_irq_disable();\n");
- printk(" lock(");
- __print_lock_name(safe_class);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(middle_class);
- printk(");\n");
- printk(" <Interrupt>\n");
- printk(" lock(");
- __print_lock_name(safe_class);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
-}
-
-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,
- enum lock_usage_bit bit2,
- const char *irqclass)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("======================================================\n");
- printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
- irqclass, irqclass);
- print_kernel_ident();
- printk("------------------------------------------------------\n");
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
- curr->comm, task_pid_nr(curr),
- curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
- curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
- curr->hardirqs_enabled,
- curr->softirqs_enabled);
- print_lock(next);
-
- printk("\nand this task is already holding:\n");
- print_lock(prev);
- printk("which would create a new lock dependency:\n");
- print_lock_name(hlock_class(prev));
- printk(" ->");
- 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_entry->class);
- printk("\n... which became %s-irq-safe at:\n", irqclass);
-
- print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
-
- printk("\nto a %s-irq-unsafe lock:\n", irqclass);
- print_lock_name(forwards_entry->class);
- printk("\n... which became %s-irq-unsafe at:\n", irqclass);
- printk("...");
-
- print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
-
- printk("\nother info that might help us debug this:\n\n");
- print_irq_lock_scenario(backwards_entry, forwards_entry,
- hlock_class(prev), hlock_class(next));
-
- lockdep_print_held_locks(curr);
-
- 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 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();
-
- return 0;
-}
-
-static int
-check_usage(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, enum lock_usage_bit bit_backwards,
- 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);
-
- 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;
-
- 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;
-
- 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
-
-static void
-print_deadlock_scenario(struct held_lock *nxt,
- struct held_lock *prv)
-{
- struct lock_class *next = hlock_class(nxt);
- struct lock_class *prev = hlock_class(prv);
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0\n");
- printk(" ----\n");
- printk(" lock(");
- __print_lock_name(prev);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(next);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
- printk(" May be due to missing lock nesting notation\n\n");
-}
-
-static int
-print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("=============================================\n");
- printk("[ INFO: possible recursive locking detected ]\n");
- print_kernel_ident();
- printk("---------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(next);
- printk("\nbut task is already holding lock:\n");
- print_lock(prev);
-
- printk("\nother info that might help us debug this:\n");
- print_deadlock_scenario(next, prev);
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Check whether we are holding such a class already.
- *
- * (Note that this has to be done separately, because the graph cannot
- * detect such classes of deadlocks.)
- *
- * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
- */
-static int
-check_deadlock(struct task_struct *curr, struct held_lock *next,
- 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->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;
-}
-
-/*
- * There was a chain-cache miss, and we are about to add a new dependency
- * to a previous lock. We recursively validate the following rules:
- *
- * - would the adding of the <prev> -> <next> dependency create a
- * circular dependency in the graph? [== circular deadlock]
- *
- * - does the new prev->next dependency connect any hardirq-safe lock
- * (in the full backwards-subgraph starting at <prev>) with any
- * hardirq-unsafe lock (in the full forwards-subgraph starting at
- * <next>)? [== illegal lock inversion with hardirq contexts]
- *
- * - does the new prev->next dependency connect any softirq-safe lock
- * (in the full backwards-subgraph starting at <prev>) with any
- * softirq-unsafe lock (in the full forwards-subgraph starting at
- * <next>)? [== illegal lock inversion with softirq contexts]
- *
- * 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, int distance, int trylock_loop)
-{
- struct lock_list *entry;
- int ret;
- struct lock_list this;
- struct lock_list *uninitialized_var(target_entry);
- /*
- * Static variable, serialized by the graph_lock().
- *
- * We use this static variable to save the stack trace in case
- * we call into this function multiple times due to encountering
- * trylocks in the held lock stack.
- */
- static struct stack_trace trace;
-
- /*
- * 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:
- */
- 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;
-
- /*
- * For recursive read-locks we do all the dependency checks,
- * but we dont store read-triggered dependencies (only
- * write-triggered dependencies). This ensures that only the
- * write-side dependencies matter, and that if for example a
- * write-lock never takes any other locks, then the reads are
- * equivalent to a NOP.
- */
- if (next->read == 2 || prev->read == 2)
- return 1;
- /*
- * Is the <prev> -> <next> dependency already present?
- *
- * (this may occur even though this is a new chain: consider
- * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
- * 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, &hlock_class(prev)->locks_after, entry) {
- if (entry->class == hlock_class(next)) {
- if (distance == 1)
- entry->distance = 1;
- return 2;
- }
- }
-
- if (!trylock_loop && !save_trace(&trace))
- return 0;
-
- /*
- * Ok, all validations passed, add the new lock
- * to the previous lock's dependency list:
- */
- ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
- &hlock_class(prev)->locks_after,
- next->acquire_ip, distance, &trace);
-
- if (!ret)
- return 0;
-
- ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
- &hlock_class(next)->locks_before,
- next->acquire_ip, distance, &trace);
- if (!ret)
- return 0;
-
- /*
- * Debugging printouts:
- */
- if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
- graph_unlock();
- printk("\n new dependency: ");
- print_lock_name(hlock_class(prev));
- printk(" => ");
- print_lock_name(hlock_class(next));
- printk("\n");
- dump_stack();
- return graph_lock();
- }
- return 1;
-}
-
-/*
- * Add the dependency to all directly-previous locks that are 'relevant'.
- * The ones that are relevant are (in increasing distance from curr):
- * all consecutive trylock entries and the final non-trylock entry - or
- * the end of this context's lock-chain - whichever comes first.
- */
-static int
-check_prevs_add(struct task_struct *curr, struct held_lock *next)
-{
- int depth = curr->lockdep_depth;
- int trylock_loop = 0;
- struct held_lock *hlock;
-
- /*
- * Debugging checks.
- *
- * Depth must not be zero for a non-head lock:
- */
- if (!depth)
- goto out_bug;
- /*
- * At least two relevant locks must exist for this
- * to be a head:
- */
- if (curr->held_locks[depth].irq_context !=
- curr->held_locks[depth-1].irq_context)
- goto out_bug;
-
- 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, trylock_loop))
- 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;
- trylock_loop = 1;
- }
- return 1;
-out_bug:
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- /*
- * Clearly we all shouldn't be here, but since we made it we
- * can reliable say we messed up our state. See the above two
- * gotos for reasons why we could possibly end up here.
- */
- WARN_ON(1);
-
- return 0;
-}
-
-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];
-
-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 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(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;
- int i, j;
-
- /*
- * We might need to take the graph lock, ensure we've got IRQs
- * disabled to make this an IRQ-safe lock.. for recursion reasons
- * lockdep won't complain about its own locking errors.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
- /*
- * We can walk it lock-free, because entries only get added
- * to the hash:
- */
- list_for_each_entry(chain, hash_head, entry) {
- if (chain->chain_key == chain_key) {
-cache_hit:
- debug_atomic_inc(chain_lookup_hits);
- 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:
- */
- 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) {
- graph_unlock();
- goto cache_hit;
- }
- }
- if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
- 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 */
- for (i = curr->lockdep_depth - 1; i >= 0; i--) {
- hlock_curr = curr->held_locks + i;
- if (hlock_curr->irq_context != hlock->irq_context)
- break;
- }
- i++;
- chain->depth = curr->lockdep_depth + 1 - i;
- if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
- chain->base = nr_chain_hlocks;
- nr_chain_hlocks += chain->depth;
- 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
-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
- * it from scratch, to make sure that it's done correctly:
- */
-static void check_chain_key(struct task_struct *curr)
-{
-#ifdef CONFIG_DEBUG_LOCKDEP
- struct held_lock *hlock, *prev_hlock = NULL;
- unsigned int i, id;
- u64 chain_key = 0;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
- if (chain_key != hlock->prev_chain_key) {
- debug_locks_off();
- /*
- * We got mighty confused, our chain keys don't match
- * with what we expect, someone trample on our task state?
- */
- 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);
- return;
- }
- id = hlock->class_idx - 1;
- /*
- * Whoops ran out of static storage again?
- */
- if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
- return;
-
- if (prev_hlock && (prev_hlock->irq_context !=
- hlock->irq_context))
- chain_key = 0;
- chain_key = iterate_chain_key(chain_key, id);
- prev_hlock = hlock;
- }
- if (chain_key != curr->curr_chain_key) {
- debug_locks_off();
- /*
- * More smoking hash instead of calculating it, damn see these
- * numbers float.. I bet that a pink elephant stepped on my memory.
- */
- 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);
- }
-#endif
-}
-
-static void
-print_usage_bug_scenario(struct held_lock *lock)
-{
- struct lock_class *class = hlock_class(lock);
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0\n");
- printk(" ----\n");
- printk(" lock(");
- __print_lock_name(class);
- printk(");\n");
- printk(" <Interrupt>\n");
- printk(" lock(");
- __print_lock_name(class);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
-}
-
-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");
- printk("=================================\n");
- printk("[ INFO: inconsistent lock state ]\n");
- print_kernel_ident();
- 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");
- print_usage_bug_scenario(this);
-
- 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_list *root, struct lock_list *other,
- struct held_lock *this, int forwards,
- const char *irqclass)
-{
- struct lock_list *entry = other;
- struct lock_list *middle = NULL;
- int depth;
-
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("=========================================================\n");
- printk("[ INFO: possible irq lock inversion dependency detected ]\n");
- print_kernel_ident();
- printk("---------------------------------------------------------\n");
- printk("%s/%d just changed the state of lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(this);
- if (forwards)
- printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
- else
- 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");
-
- /* Find a middle lock (if one exists) */
- depth = get_lock_depth(other);
- do {
- if (depth == 0 && (entry != root)) {
- printk("lockdep:%s bad path found in chain graph\n", __func__);
- break;
- }
- middle = entry;
- entry = get_lock_parent(entry);
- depth--;
- } while (entry && entry != root && (depth >= 0));
- if (forwards)
- print_irq_lock_scenario(root, other,
- middle ? middle->class : root->class, other->class);
- else
- print_irq_lock_scenario(other, root,
- middle ? middle->class : other->class, root->class);
-
- lockdep_print_held_locks(curr);
-
- 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();
-
- return 0;
-}
-
-/*
- * Prove that in the forwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_forwards(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit bit, const char *irqclass)
-{
- int ret;
- 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, &root, target_entry,
- this, 1, irqclass);
-}
-
-/*
- * Prove that in the backwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_backwards(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit bit, const char *irqclass)
-{
- int ret;
- 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, &root, target_entry,
- this, 0, irqclass);
-}
-
-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->hardirq_enable_ip);
- printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
- print_ip_sym(curr->hardirq_disable_ip);
- printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
- print_ip_sym(curr->softirq_enable_ip);
- printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
- print_ip_sym(curr->softirq_disable_ip);
-}
-
-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;
-}
-
-static int RECLAIM_FS_verbose(struct lock_class *class)
-{
-#if RECLAIM_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-#define STRICT_READ_CHECKS 1
-
-static int (*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;
-
- /*
- * Validate that the lock dependencies don't have conflicting usage
- * states.
- */
- if ((!read || !dir || STRICT_READ_CHECKS) &&
- !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
- return 0;
-
- /*
- * Check for read in write conflicts
- */
- if (!read) {
- if (!valid_state(curr, this, new_bit, excl_bit + 1))
- return 0;
-
- if (STRICT_READ_CHECKS &&
- !usage(curr, this, excl_bit + 1,
- state_name(new_bit + 1)))
- return 0;
- }
-
- if (state_verbose(new_bit, hlock_class(this)))
- return 2;
-
- return 1;
-}
-
-enum mark_type {
-#define LOCKDEP_STATE(__STATE) __STATE,
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-/*
- * Mark all held locks with a usage bit:
- */
-static int
-mark_held_locks(struct task_struct *curr, enum mark_type mark)
-{
- enum lock_usage_bit usage_bit;
- struct held_lock *hlock;
- int i;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
-
- usage_bit = 2 + (mark << 2); /* ENABLED */
- if (hlock->read)
- usage_bit += 1; /* READ */
-
- BUG_ON(usage_bit >= LOCK_USAGE_STATES);
-
- if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys)
- continue;
-
- if (!mark_lock(curr, hlock, usage_bit))
- return 0;
- }
-
- return 1;
-}
-
-/*
- * Hardirqs will be enabled:
- */
-static void __trace_hardirqs_on_caller(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- /* we'll do an OFF -> ON transition: */
- curr->hardirqs_enabled = 1;
-
- /*
- * We are going to turn hardirqs on, so set the
- * usage bit for all held locks:
- */
- if (!mark_held_locks(curr, HARDIRQ))
- return;
- /*
- * If we have softirqs enabled, then set the usage
- * bit for all held locks. (disabled hardirqs prevented
- * this bit from being set before)
- */
- if (curr->softirqs_enabled)
- 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);
-}
-
-void trace_hardirqs_on_caller(unsigned long ip)
-{
- time_hardirqs_on(CALLER_ADDR0, ip);
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- if (unlikely(current->hardirqs_enabled)) {
- /*
- * Neither irq nor preemption are disabled here
- * so this is racy by nature but losing one hit
- * in a stat is not a big deal.
- */
- __debug_atomic_inc(redundant_hardirqs_on);
- return;
- }
-
- /*
- * We're enabling irqs and according to our state above irqs weren't
- * already enabled, yet we find the hardware thinks they are in fact
- * enabled.. someone messed up their IRQ state tracing.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- /*
- * See the fine text that goes along with this variable definition.
- */
- if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
- return;
-
- /*
- * Can't allow enabling interrupts while in an interrupt handler,
- * that's general bad form and such. Recursion, limited stack etc..
- */
- if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
- return;
-
- current->lockdep_recursion = 1;
- __trace_hardirqs_on_caller(ip);
- current->lockdep_recursion = 0;
-}
-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_caller(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- time_hardirqs_off(CALLER_ADDR0, ip);
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- /*
- * So we're supposed to get called after you mask local IRQs, but for
- * some reason the hardware doesn't quite think you did a proper job.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->hardirqs_enabled) {
- /*
- * We have done an ON -> OFF transition:
- */
- curr->hardirqs_enabled = 0;
- 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);
-
-/*
- * Softirqs will be enabled:
- */
-void trace_softirqs_on(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- /*
- * We fancy IRQs being disabled here, see softirq.c, avoids
- * funny state and nesting things.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->softirqs_enabled) {
- debug_atomic_inc(redundant_softirqs_on);
- return;
- }
-
- current->lockdep_recursion = 1;
- /*
- * 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);
- current->lockdep_recursion = 0;
-}
-
-/*
- * Softirqs were disabled:
- */
-void trace_softirqs_off(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- /*
- * We fancy IRQs being disabled here, see softirq.c
- */
- 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);
- /*
- * Whoops, we wanted softirqs off, so why aren't they?
- */
- 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;
-
- /*
- * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
- */
- 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 /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
-static inline
-int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
- 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 /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
-/*
- * 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 didn't 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 (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, int subclass)
-{
- int i;
-
- kmemcheck_mark_initialized(lock, sizeof(*lock));
-
- for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
- lock->class_cache[i] = NULL;
-
-#ifdef CONFIG_LOCK_STAT
- lock->cpu = raw_smp_processor_id();
-#endif
-
- /*
- * Can't be having no nameless bastards around this place!
- */
- if (DEBUG_LOCKS_WARN_ON(!name)) {
- lock->name = "NULL";
- return;
- }
-
- lock->name = name;
-
- /*
- * No key, no joy, we need to hash something.
- */
- if (DEBUG_LOCKS_WARN_ON(!key))
- return;
- /*
- * Sanity check, the lock-class key must be persistent:
- */
- if (!static_obj(key)) {
- printk("BUG: key %p not in .data!\n", key);
- /*
- * What it says above ^^^^^, I suggest you read it.
- */
- DEBUG_LOCKS_WARN_ON(1);
- return;
- }
- lock->key = key;
-
- if (unlikely(!debug_locks))
- return;
-
- if (subclass)
- register_lock_class(lock, subclass, 1);
-}
-EXPORT_SYMBOL_GPL(lockdep_init_map);
-
-struct lock_class_key __lockdep_no_validate__;
-EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
-
-static int
-print_lock_nested_lock_not_held(struct task_struct *curr,
- struct held_lock *hlock,
- unsigned long ip)
-{
- if (!debug_locks_off())
- return 0;
- if (debug_locks_silent)
- return 0;
-
- printk("\n");
- printk("==================================\n");
- printk("[ BUG: Nested lock was not taken ]\n");
- print_kernel_ident();
- printk("----------------------------------\n");
-
- printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
- print_lock(hlock);
-
- printk("\nbut this task is not holding:\n");
- printk("%s\n", hlock->nest_lock->name);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static int __lock_is_held(struct lockdep_map *lock);
-
-/*
- * This gets called for every mutex_lock*()/spin_lock*() operation.
- * We maintain the dependency maps and validate the locking attempt:
- */
-static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
- int trylock, int read, int check, int hardirqs_off,
- 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;
-
- /*
- * Lockdep should run with IRQs disabled, otherwise we could
- * get an interrupt which would want to take locks, which would
- * end up in lockdep and have you got a head-ache already?
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (lock->key == &__lockdep_no_validate__)
- check = 1;
-
- if (subclass < NR_LOCKDEP_CACHING_CLASSES)
- class = lock->class_cache[subclass];
- /*
- * Not cached?
- */
- if (unlikely(!class)) {
- class = register_lock_class(lock, subclass, 0);
- if (!class)
- return 0;
- }
- atomic_inc((atomic_t *)&class->ops);
- if (very_verbose(class)) {
- printk("\nacquire class [%p] %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
- }
-
- /*
- * Add the lock to the list of currently held locks.
- * (we dont increase the depth just yet, up until the
- * dependency checks are done)
- */
- depth = curr->lockdep_depth;
- /*
- * Ran out of static storage for our per-task lock stack again have we?
- */
- if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
- return 0;
-
- 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 = curr->held_locks + depth;
- /*
- * Plain impossible, we just registered it and checked it weren't no
- * NULL like.. I bet this mushroom I ate was good!
- */
- 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;
- hlock->references = references;
-#ifdef CONFIG_LOCK_STAT
- hlock->waittime_stamp = 0;
- hlock->holdtime_stamp = lockstat_clock();
-#endif
-
- if (check == 2 && !mark_irqflags(curr, hlock))
- return 0;
-
- /* mark it as used: */
- if (!mark_lock(curr, hlock, LOCK_USED))
- return 0;
-
- /*
- * 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;
- /*
- * Whoops, we did it again.. ran straight out of our static allocation.
- */
- if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
- return 0;
-
- chain_key = curr->curr_chain_key;
- if (!depth) {
- /*
- * How can we have a chain hash when we ain't got no keys?!
- */
- if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
- return 0;
- 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 (nest_lock && !__lock_is_held(nest_lock))
- return print_lock_nested_lock_not_held(curr, hlock, ip);
-
- 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();
- print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
- printk(KERN_DEBUG "depth: %i max: %lu!\n",
- curr->lockdep_depth, MAX_LOCK_DEPTH);
-
- lockdep_print_held_locks(current);
- debug_show_all_locks();
- dump_stack();
-
- return 0;
- }
-
- if (unlikely(curr->lockdep_depth > max_lockdep_depth))
- max_lockdep_depth = curr->lockdep_depth;
-
- return 1;
-}
-
-static int
-print_unlock_imbalance_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");
- printk("=====================================\n");
- printk("[ BUG: bad unlock balance detected! ]\n");
- print_kernel_ident();
- 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;
- /*
- * Lockdep should run with IRQs disabled, recursion, head-ache, etc..
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (curr->lockdep_depth <= 0)
- return print_unlock_imbalance_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[0];
-
- if (!class)
- class = look_up_lock_class(lock, 0);
-
- /*
- * If look_up_lock_class() failed to find a class, we're trying
- * to test if we hold a lock that has never yet been acquired.
- * Clearly if the lock hasn't been acquired _ever_, we're not
- * holding it either, so report failure.
- */
- if (!class)
- return 0;
-
- /*
- * References, but not a lock we're actually ref-counting?
- * State got messed up, follow the sites that change ->references
- * and try to make sense of it.
- */
- 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;
- /*
- * This function is about (re)setting the class of a held lock,
- * yet we're not actually holding any locks. Naughty user!
- */
- 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_imbalance_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,
- hlock->references))
- return 0;
- }
-
- /*
- * I took it apart and put it back together again, except now I have
- * these 'spare' parts.. where shall I put them.
- */
- 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
- * relatively rare operation, as all the unlock APIs default
- * to nested mode (which uses lock_release()):
- */
-static int
-lock_release_non_nested(struct task_struct *curr,
- struct lockdep_map *lock, unsigned long ip)
-{
- struct held_lock *hlock, *prev_hlock;
- unsigned int depth;
- int i;
-
- /*
- * Check whether the lock exists in the current stack
- * of held locks:
- */
- depth = curr->lockdep_depth;
- /*
- * So we're all set to release this lock.. wait what lock? We don't
- * own any locks, you've been drinking again?
- */
- 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_imbalance_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(hlock)->subclass, hlock->trylock,
- hlock->read, hlock->check, hlock->hardirqs_off,
- hlock->nest_lock, hlock->acquire_ip,
- hlock->references))
- return 0;
- }
-
- /*
- * We had N bottles of beer on the wall, we drank one, but now
- * there's not N-1 bottles of beer left on the wall...
- */
- if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
- return 0;
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static int lock_release_nested(struct task_struct *curr,
- struct lockdep_map *lock, unsigned long ip)
-{
- struct held_lock *hlock;
- unsigned int depth;
-
- /*
- * Pop off the top of the lock stack:
- */
- depth = curr->lockdep_depth - 1;
- hlock = curr->held_locks + depth;
-
- /*
- * Is the unlock non-nested:
- */
- if (hlock->instance != lock || hlock->references)
- return lock_release_non_nested(curr, lock, ip);
- curr->lockdep_depth--;
-
- /*
- * No more locks, but somehow we've got hash left over, who left it?
- */
- if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
- 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_idx = 0;
- hlock->acquire_ip = 0;
- hlock->irq_context = 0;
-#endif
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static void
-__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (!check_unlock(curr, lock, ip))
- return;
-
- if (nested) {
- if (!lock_release_nested(curr, lock, ip))
- return;
- } else {
- if (!lock_release_non_nested(curr, lock, ip))
- return;
- }
-
- 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_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
- defined(CONFIG_TRACE_IRQFLAGS)
- if (!debug_locks)
- return;
-
- 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.
- * hardirq contexts (such as on 4KSTACKS), so only
- * check if not in hardirq contexts:
- */
- if (!hardirq_count()) {
- if (softirq_count()) {
- /* like the above, but with softirqs */
- DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
- } else {
- /* lick the above, does it taste good? */
- DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
- }
- }
-
- if (!debug_locks)
- print_irqtrace_events(current);
-#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,
- struct lockdep_map *nest_lock, unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
-
- current->lockdep_recursion = 1;
- trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
- __lock_acquire(lock, subclass, trylock, read, check,
- 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)
-{
- unsigned long flags;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- trace_lock_release(lock, ip);
- __lock_release(lock, nested, ip);
- 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 1; /* avoid false negative lockdep_assert_held() */
-
- 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");
- printk("=================================\n");
- printk("[ BUG: bad contention detected! ]\n");
- print_kernel_ident();
- 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;
- /*
- * Whee, we contended on this lock, except it seems we're not
- * actually trying to acquire anything much at all..
- */
- 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 = lockstat_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, waittime = 0;
- int i, cpu;
-
- depth = curr->lockdep_depth;
- /*
- * Yay, we acquired ownership of this lock we didn't try to
- * acquire, how the heck did that happen?
- */
- 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 = lockstat_clock();
- waittime = now - hlock->waittime_stamp;
- hlock->holdtime_stamp = now;
- }
-
- trace_lock_acquired(lock, ip);
-
- 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;
- trace_lock_contended(lock, ip);
- __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;
- current->lockdep_depth = 0;
- current->lockdep_recursion = 0;
- memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
- nr_hardirq_chains = 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);
-}
-
-static void zap_class(struct lock_class *class)
-{
- int i;
-
- /*
- * Remove all dependencies this lock is
- * involved in:
- */
- for (i = 0; i < nr_list_entries; i++) {
- if (list_entries[i].class == class)
- list_del_rcu(&list_entries[i].entry);
- }
- /*
- * Unhash the class and remove it from the all_lock_classes list:
- */
- list_del_rcu(&class->hash_entry);
- list_del_rcu(&class->lock_entry);
-
- class->key = NULL;
-}
-
-static inline int within(const void *addr, void *start, unsigned long size)
-{
- return addr >= start && addr < start + size;
-}
-
-void lockdep_free_key_range(void *start, unsigned long size)
-{
- struct lock_class *class, *next;
- struct list_head *head;
- unsigned long flags;
- int i;
- int locked;
-
- raw_local_irq_save(flags);
- locked = graph_lock();
-
- /*
- * Unhash all classes that were created by this module:
- */
- 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 (within(class->key, start, size))
- zap_class(class);
- else if (within(class->name, start, size))
- zap_class(class);
- }
- }
-
- if (locked)
- graph_unlock();
- raw_local_irq_restore(flags);
-}
-
-void lockdep_reset_lock(struct lockdep_map *lock)
-{
- struct lock_class *class, *next;
- struct list_head *head;
- unsigned long flags;
- int i, j;
- int locked;
-
- raw_local_irq_save(flags);
-
- /*
- * Remove all classes this lock might have:
- */
- for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
- /*
- * If the class exists we look it up and zap it:
- */
- class = look_up_lock_class(lock, j);
- if (class)
- zap_class(class);
- }
- /*
- * Debug check: in the end all mapped classes should
- * be gone.
- */
- 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) {
- int match = 0;
-
- for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
- match |= class == lock->class_cache[j];
-
- if (unlikely(match)) {
- if (debug_locks_off_graph_unlock()) {
- /*
- * We all just reset everything, how did it match?
- */
- WARN_ON(1);
- }
- goto out_restore;
- }
- }
- }
- if (locked)
- graph_unlock();
-
-out_restore:
- raw_local_irq_restore(flags);
-}
-
-void lockdep_init(void)
-{
- int i;
-
- /*
- * Some architectures have their own start_kernel()
- * code which calls lockdep_init(), while we also
- * call lockdep_init() from the start_kernel() itself,
- * and we want to initialize the hashes only once:
- */
- if (lockdep_initialized)
- return;
-
- for (i = 0; i < CLASSHASH_SIZE; i++)
- INIT_LIST_HEAD(classhash_table + i);
-
- for (i = 0; i < CHAINHASH_SIZE; i++)
- INIT_LIST_HEAD(chainhash_table + i);
-
- lockdep_initialized = 1;
-}
-
-void __init lockdep_info(void)
-{
- printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
-
- 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("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
- printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
- printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
-
- printk(" memory used by lock dependency info: %lu kB\n",
- (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
- 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
-#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! lock-%s was acquired"
- "before lockdep_init\n", lock_init_error);
- printk("Call stack leading to lockdep invocation was:\n");
- print_stack_trace(&lockdep_init_trace, 0);
- }
-#endif
-}
-
-static void
-print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
- const void *mem_to, struct held_lock *hlock)
-{
- if (!debug_locks_off())
- return;
- if (debug_locks_silent)
- return;
-
- printk("\n");
- printk("=========================\n");
- printk("[ BUG: held lock freed! ]\n");
- print_kernel_ident();
- printk("-------------------------\n");
- printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
- curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
- print_lock(hlock);
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- 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
- * any held lock in the memory range of <from> to <to>:
- */
-void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
-{
- struct task_struct *curr = current;
- struct held_lock *hlock;
- unsigned long flags;
- int i;
-
- if (unlikely(!debug_locks))
- return;
-
- local_irq_save(flags);
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
-
- if (not_in_range(mem_from, mem_len, hlock->instance,
- sizeof(*hlock->instance)))
- continue;
-
- 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(void)
-{
- if (!debug_locks_off())
- return;
- if (debug_locks_silent)
- return;
-
- printk("\n");
- printk("=====================================\n");
- printk("[ BUG: %s/%d still has locks held! ]\n",
- current->comm, task_pid_nr(current));
- print_kernel_ident();
- printk("-------------------------------------\n");
- lockdep_print_held_locks(current);
- printk("\nstack backtrace:\n");
- dump_stack();
-}
-
-void debug_check_no_locks_held(void)
-{
- if (unlikely(current->lockdep_depth > 0))
- print_held_locks_bug();
-}
-EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
-
-void debug_show_all_locks(void)
-{
- struct task_struct *g, *p;
- 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");
-
- /*
- * Here we try to get the tasklist_lock as hard as possible,
- * if not successful after 2 seconds we ignore it (but keep
- * trying). This is to enable a debug printout even if a
- * tasklist_lock-holding task deadlocks or crashes.
- */
-retry:
- if (!read_trylock(&tasklist_lock)) {
- if (count == 10)
- printk("hm, tasklist_lock locked, retrying... ");
- if (count) {
- count--;
- printk(" #%d", 10-count);
- mdelay(200);
- goto retry;
- }
- printk(" ignoring it.\n");
- unlock = 0;
- } else {
- if (count != 10)
- printk(KERN_CONT " 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 (read_trylock(&tasklist_lock))
- unlock = 1;
- } while_each_thread(g, p);
-
- printk("\n");
- printk("=============================================\n\n");
-
- if (unlock)
- read_unlock(&tasklist_lock);
-}
-EXPORT_SYMBOL_GPL(debug_show_all_locks);
-
-/*
- * 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 lockdep_sys_exit(void)
-{
- struct task_struct *curr = current;
-
- if (unlikely(curr->lockdep_depth)) {
- if (!debug_locks_off())
- return;
- printk("\n");
- printk("================================================\n");
- printk("[ BUG: lock held when returning to user space! ]\n");
- print_kernel_ident();
- printk("------------------------------------------------\n");
- printk("%s/%d is leaving the kernel with locks still held!\n",
- curr->comm, curr->pid);
- lockdep_print_held_locks(curr);
- }
-}
-
-void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
-{
- struct task_struct *curr = current;
-
-#ifndef CONFIG_PROVE_RCU_REPEATEDLY
- if (!debug_locks_off())
- return;
-#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
- /* Note: the following can be executed concurrently, so be careful. */
- printk("\n");
- printk("===============================\n");
- printk("[ INFO: suspicious RCU usage. ]\n");
- print_kernel_ident();
- printk("-------------------------------\n");
- printk("%s:%d %s!\n", file, line, s);
- printk("\nother info that might help us debug this:\n\n");
- printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
- !rcu_lockdep_current_cpu_online()
- ? "RCU used illegally from offline CPU!\n"
- : !rcu_is_watching()
- ? "RCU used illegally from idle CPU!\n"
- : "",
- rcu_scheduler_active, debug_locks);
-
- /*
- * If a CPU is in the RCU-free window in idle (ie: in the section
- * between rcu_idle_enter() and rcu_idle_exit(), then RCU
- * considers that CPU to be in an "extended quiescent state",
- * which means that RCU will be completely ignoring that CPU.
- * Therefore, rcu_read_lock() and friends have absolutely no
- * effect on a CPU running in that state. In other words, even if
- * such an RCU-idle CPU has called rcu_read_lock(), RCU might well
- * delete data structures out from under it. RCU really has no
- * choice here: we need to keep an RCU-free window in idle where
- * the CPU may possibly enter into low power mode. This way we can
- * notice an extended quiescent state to other CPUs that started a grace
- * period. Otherwise we would delay any grace period as long as we run
- * in the idle task.
- *
- * So complain bitterly if someone does call rcu_read_lock(),
- * rcu_read_lock_bh() and so on from extended quiescent states.
- */
- if (!rcu_is_watching())
- printk("RCU used illegally from extended quiescent state!\n");
-
- lockdep_print_held_locks(curr);
- printk("\nstack backtrace:\n");
- dump_stack();
-}
-EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);