lockdep: add lock_class information to lock_chain and output it
This patch records array of lock_class into lock_chain, and export lock_chain information via /proc/lockdep_chains. It is based on x86/master branch of git-x86 tree, and has been tested on x86_64 platform. Signed-off-by: Huang Ying <ying.huang@intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Huang, Ying
Ingo Molnar
parent
2429e4ee78
commit
443cd507ce
4 changed files with 135 additions and 3 deletions
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@ -182,6 +182,9 @@ struct lock_list {
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* We record lock dependency chains, so that we can cache them:
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*/
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struct lock_chain {
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u8 irq_context;
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u8 depth;
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u16 base;
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struct list_head entry;
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u64 chain_key;
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};
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@ -1458,7 +1458,14 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
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}
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unsigned long nr_lock_chains;
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static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
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struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
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atomic_t nr_chain_hlocks;
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static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
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struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
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{
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return lock_classes + chain_hlocks[chain->base + i];
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}
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/*
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* Look up a dependency chain. If the key is not present yet then
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@ -1466,10 +1473,15 @@ static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
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* validated. If the key is already hashed, return 0.
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* (On return with 1 graph_lock is held.)
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*/
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static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
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static inline int lookup_chain_cache(struct task_struct *curr,
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struct held_lock *hlock,
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u64 chain_key)
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{
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struct lock_class *class = hlock->class;
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struct list_head *hash_head = chainhashentry(chain_key);
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struct lock_chain *chain;
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struct held_lock *hlock_curr, *hlock_next;
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int i, j, n;
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if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
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return 0;
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@ -1517,6 +1529,26 @@ static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
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}
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chain = lock_chains + nr_lock_chains++;
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chain->chain_key = chain_key;
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chain->irq_context = hlock->irq_context;
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/* Find the first held_lock of current chain */
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hlock_next = hlock;
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for (i = curr->lockdep_depth - 1; i >= 0; i--) {
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hlock_curr = curr->held_locks + i;
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if (hlock_curr->irq_context != hlock_next->irq_context)
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break;
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hlock_next = hlock;
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}
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i++;
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chain->depth = curr->lockdep_depth + 1 - i;
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n = atomic_add_return(chain->depth, &nr_chain_hlocks);
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if (unlikely(n < MAX_LOCKDEP_CHAIN_HLOCKS)) {
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chain->base = n - chain->depth;
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for (j = 0; j < chain->depth - 1; j++, i++) {
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int lock_id = curr->held_locks[i].class - lock_classes;
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chain_hlocks[chain->base + j] = lock_id;
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}
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chain_hlocks[chain->base + j] = class - lock_classes;
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}
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list_add_tail_rcu(&chain->entry, hash_head);
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debug_atomic_inc(&chain_lookup_misses);
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inc_chains();
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@ -1538,7 +1570,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
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* graph_lock for us)
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*/
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if (!hlock->trylock && (hlock->check == 2) &&
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lookup_chain_cache(chain_key, hlock->class)) {
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lookup_chain_cache(curr, hlock, chain_key)) {
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/*
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* Check whether last held lock:
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*
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@ -23,6 +23,8 @@
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#define MAX_LOCKDEP_CHAINS_BITS 14
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#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
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#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
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/*
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* Stack-trace: tightly packed array of stack backtrace
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* addresses. Protected by the hash_lock.
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@ -30,15 +32,19 @@
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#define MAX_STACK_TRACE_ENTRIES 262144UL
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extern struct list_head all_lock_classes;
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extern struct lock_chain lock_chains[];
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extern void
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get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
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extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
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struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
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extern unsigned long nr_lock_classes;
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extern unsigned long nr_list_entries;
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extern unsigned long nr_lock_chains;
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extern atomic_t nr_chain_hlocks;
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extern unsigned long nr_stack_trace_entries;
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extern unsigned int nr_hardirq_chains;
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@ -178,6 +178,93 @@ static const struct file_operations proc_lockdep_operations = {
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.release = seq_release,
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};
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static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
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{
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struct lock_chain *chain;
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(*pos)++;
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if (v == SEQ_START_TOKEN)
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chain = m->private;
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else {
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chain = v;
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if (*pos < nr_lock_chains)
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chain = lock_chains + *pos;
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else
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chain = NULL;
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}
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return chain;
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}
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static void *lc_start(struct seq_file *m, loff_t *pos)
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{
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if (*pos == 0)
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return SEQ_START_TOKEN;
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if (*pos < nr_lock_chains)
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return lock_chains + *pos;
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return NULL;
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}
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static void lc_stop(struct seq_file *m, void *v)
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{
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}
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static int lc_show(struct seq_file *m, void *v)
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{
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struct lock_chain *chain = v;
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struct lock_class *class;
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int i;
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if (v == SEQ_START_TOKEN) {
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seq_printf(m, "all lock chains:\n");
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return 0;
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}
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seq_printf(m, "irq_context: %d\n", chain->irq_context);
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for (i = 0; i < chain->depth; i++) {
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class = lock_chain_get_class(chain, i);
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seq_printf(m, "[%p] ", class->key);
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print_name(m, class);
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seq_puts(m, "\n");
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}
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seq_puts(m, "\n");
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return 0;
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}
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static const struct seq_operations lockdep_chains_ops = {
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.start = lc_start,
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.next = lc_next,
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.stop = lc_stop,
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.show = lc_show,
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};
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static int lockdep_chains_open(struct inode *inode, struct file *file)
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{
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int res = seq_open(file, &lockdep_chains_ops);
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if (!res) {
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struct seq_file *m = file->private_data;
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if (nr_lock_chains)
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m->private = lock_chains;
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else
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m->private = NULL;
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}
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return res;
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}
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static const struct file_operations proc_lockdep_chains_operations = {
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.open = lockdep_chains_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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static void lockdep_stats_debug_show(struct seq_file *m)
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{
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#ifdef CONFIG_DEBUG_LOCKDEP
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@ -294,6 +381,8 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
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#ifdef CONFIG_PROVE_LOCKING
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seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
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nr_lock_chains, MAX_LOCKDEP_CHAINS);
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seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
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atomic_read(&nr_chain_hlocks), MAX_LOCKDEP_CHAIN_HLOCKS);
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#endif
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#ifdef CONFIG_TRACE_IRQFLAGS
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@ -661,6 +750,8 @@ static const struct file_operations proc_lock_stat_operations = {
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static int __init lockdep_proc_init(void)
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{
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proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
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proc_create("lockdep_chains", S_IRUSR, NULL,
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&proc_lockdep_chains_operations);
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proc_create("lockdep_stats", S_IRUSR, NULL,
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&proc_lockdep_stats_operations);
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