v4.19.13 snapshot.
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
new file mode 100644
index 0000000..3dd980d
--- /dev/null
+++ b/kernel/locking/lockdep_proc.c
@@ -0,0 +1,663 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/lockdep_proc.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
+ *
+ * Code for /proc/lockdep and /proc/lockdep_stats:
+ *
+ */
+#include <linux/export.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/debug_locks.h>
+#include <linux/vmalloc.h>
+#include <linux/sort.h>
+#include <linux/uaccess.h>
+#include <asm/div64.h>
+
+#include "lockdep_internals.h"
+
+static void *l_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ return seq_list_next(v, &all_lock_classes, pos);
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+ return seq_list_start_head(&all_lock_classes, *pos);
+}
+
+static void l_stop(struct seq_file *m, void *v)
+{
+}
+
+static void print_name(struct seq_file *m, struct lock_class *class)
+{
+ char str[KSYM_NAME_LEN];
+ const char *name = class->name;
+
+ if (!name) {
+ name = __get_key_name(class->key, str);
+ seq_printf(m, "%s", name);
+ } else{
+ seq_printf(m, "%s", name);
+ if (class->name_version > 1)
+ seq_printf(m, "#%d", class->name_version);
+ if (class->subclass)
+ seq_printf(m, "/%d", class->subclass);
+ }
+}
+
+static int l_show(struct seq_file *m, void *v)
+{
+ struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
+ struct lock_list *entry;
+ char usage[LOCK_USAGE_CHARS];
+
+ if (v == &all_lock_classes) {
+ seq_printf(m, "all lock classes:\n");
+ return 0;
+ }
+
+ seq_printf(m, "%p", class->key);
+#ifdef CONFIG_DEBUG_LOCKDEP
+ seq_printf(m, " OPS:%8ld", class->ops);
+#endif
+#ifdef CONFIG_PROVE_LOCKING
+ seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
+ seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
+#endif
+
+ get_usage_chars(class, usage);
+ seq_printf(m, " %s", usage);
+
+ seq_printf(m, ": ");
+ print_name(m, class);
+ seq_puts(m, "\n");
+
+ list_for_each_entry(entry, &class->locks_after, entry) {
+ if (entry->distance == 1) {
+ seq_printf(m, " -> [%p] ", entry->class->key);
+ print_name(m, entry->class);
+ seq_puts(m, "\n");
+ }
+ }
+ seq_puts(m, "\n");
+
+ return 0;
+}
+
+static const struct seq_operations lockdep_ops = {
+ .start = l_start,
+ .next = l_next,
+ .stop = l_stop,
+ .show = l_show,
+};
+
+#ifdef CONFIG_PROVE_LOCKING
+static void *lc_start(struct seq_file *m, loff_t *pos)
+{
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ if (*pos - 1 < nr_lock_chains)
+ return lock_chains + (*pos - 1);
+
+ return NULL;
+}
+
+static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ (*pos)++;
+ return lc_start(m, pos);
+}
+
+static void lc_stop(struct seq_file *m, void *v)
+{
+}
+
+static int lc_show(struct seq_file *m, void *v)
+{
+ struct lock_chain *chain = v;
+ struct lock_class *class;
+ int i;
+
+ if (v == SEQ_START_TOKEN) {
+ if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
+ seq_printf(m, "(buggered) ");
+ seq_printf(m, "all lock chains:\n");
+ return 0;
+ }
+
+ seq_printf(m, "irq_context: %d\n", chain->irq_context);
+
+ for (i = 0; i < chain->depth; i++) {
+ class = lock_chain_get_class(chain, i);
+ if (!class->key)
+ continue;
+
+ seq_printf(m, "[%p] ", class->key);
+ print_name(m, class);
+ seq_puts(m, "\n");
+ }
+ seq_puts(m, "\n");
+
+ return 0;
+}
+
+static const struct seq_operations lockdep_chains_ops = {
+ .start = lc_start,
+ .next = lc_next,
+ .stop = lc_stop,
+ .show = lc_show,
+};
+#endif /* CONFIG_PROVE_LOCKING */
+
+static void lockdep_stats_debug_show(struct seq_file *m)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+ unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
+ hi2 = debug_atomic_read(hardirqs_off_events),
+ hr1 = debug_atomic_read(redundant_hardirqs_on),
+ hr2 = debug_atomic_read(redundant_hardirqs_off),
+ si1 = debug_atomic_read(softirqs_on_events),
+ si2 = debug_atomic_read(softirqs_off_events),
+ sr1 = debug_atomic_read(redundant_softirqs_on),
+ sr2 = debug_atomic_read(redundant_softirqs_off);
+
+ seq_printf(m, " chain lookup misses: %11llu\n",
+ debug_atomic_read(chain_lookup_misses));
+ seq_printf(m, " chain lookup hits: %11llu\n",
+ debug_atomic_read(chain_lookup_hits));
+ seq_printf(m, " cyclic checks: %11llu\n",
+ debug_atomic_read(nr_cyclic_checks));
+ seq_printf(m, " redundant checks: %11llu\n",
+ debug_atomic_read(nr_redundant_checks));
+ seq_printf(m, " redundant links: %11llu\n",
+ debug_atomic_read(nr_redundant));
+ seq_printf(m, " find-mask forwards checks: %11llu\n",
+ debug_atomic_read(nr_find_usage_forwards_checks));
+ seq_printf(m, " find-mask backwards checks: %11llu\n",
+ debug_atomic_read(nr_find_usage_backwards_checks));
+
+ seq_printf(m, " hardirq on events: %11llu\n", hi1);
+ seq_printf(m, " hardirq off events: %11llu\n", hi2);
+ seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
+ seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
+ seq_printf(m, " softirq on events: %11llu\n", si1);
+ seq_printf(m, " softirq off events: %11llu\n", si2);
+ seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
+ seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
+#endif
+}
+
+static int lockdep_stats_show(struct seq_file *m, void *v)
+{
+ struct lock_class *class;
+ unsigned long nr_unused = 0, nr_uncategorized = 0,
+ nr_irq_safe = 0, nr_irq_unsafe = 0,
+ nr_softirq_safe = 0, nr_softirq_unsafe = 0,
+ nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
+ nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
+ nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
+ nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
+ sum_forward_deps = 0;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+
+ if (class->usage_mask == 0)
+ nr_unused++;
+ if (class->usage_mask == LOCKF_USED)
+ nr_uncategorized++;
+ if (class->usage_mask & LOCKF_USED_IN_IRQ)
+ nr_irq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_IRQ)
+ nr_irq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
+ nr_softirq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
+ nr_softirq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
+ nr_hardirq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
+ nr_hardirq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
+ nr_irq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
+ nr_irq_read_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
+ nr_softirq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
+ nr_softirq_read_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
+ nr_hardirq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
+ nr_hardirq_read_unsafe++;
+
+#ifdef CONFIG_PROVE_LOCKING
+ sum_forward_deps += lockdep_count_forward_deps(class);
+#endif
+ }
+#ifdef CONFIG_DEBUG_LOCKDEP
+ DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
+#endif
+ seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
+ nr_lock_classes, MAX_LOCKDEP_KEYS);
+ seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
+ nr_list_entries, MAX_LOCKDEP_ENTRIES);
+ seq_printf(m, " indirect dependencies: %11lu\n",
+ sum_forward_deps);
+
+ /*
+ * Total number of dependencies:
+ *
+ * All irq-safe locks may nest inside irq-unsafe locks,
+ * plus all the other known dependencies:
+ */
+ seq_printf(m, " all direct dependencies: %11lu\n",
+ nr_irq_unsafe * nr_irq_safe +
+ nr_hardirq_unsafe * nr_hardirq_safe +
+ nr_list_entries);
+
+#ifdef CONFIG_PROVE_LOCKING
+ seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
+ nr_lock_chains, MAX_LOCKDEP_CHAINS);
+ seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
+ nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+ seq_printf(m, " in-hardirq chains: %11u\n",
+ nr_hardirq_chains);
+ seq_printf(m, " in-softirq chains: %11u\n",
+ nr_softirq_chains);
+#endif
+ seq_printf(m, " in-process chains: %11u\n",
+ nr_process_chains);
+ seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
+ nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
+ seq_printf(m, " combined max dependencies: %11u\n",
+ (nr_hardirq_chains + 1) *
+ (nr_softirq_chains + 1) *
+ (nr_process_chains + 1)
+ );
+ seq_printf(m, " hardirq-safe locks: %11lu\n",
+ nr_hardirq_safe);
+ seq_printf(m, " hardirq-unsafe locks: %11lu\n",
+ nr_hardirq_unsafe);
+ seq_printf(m, " softirq-safe locks: %11lu\n",
+ nr_softirq_safe);
+ seq_printf(m, " softirq-unsafe locks: %11lu\n",
+ nr_softirq_unsafe);
+ seq_printf(m, " irq-safe locks: %11lu\n",
+ nr_irq_safe);
+ seq_printf(m, " irq-unsafe locks: %11lu\n",
+ nr_irq_unsafe);
+
+ seq_printf(m, " hardirq-read-safe locks: %11lu\n",
+ nr_hardirq_read_safe);
+ seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
+ nr_hardirq_read_unsafe);
+ seq_printf(m, " softirq-read-safe locks: %11lu\n",
+ nr_softirq_read_safe);
+ seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
+ nr_softirq_read_unsafe);
+ seq_printf(m, " irq-read-safe locks: %11lu\n",
+ nr_irq_read_safe);
+ seq_printf(m, " irq-read-unsafe locks: %11lu\n",
+ nr_irq_read_unsafe);
+
+ seq_printf(m, " uncategorized locks: %11lu\n",
+ nr_uncategorized);
+ seq_printf(m, " unused locks: %11lu\n",
+ nr_unused);
+ seq_printf(m, " max locking depth: %11u\n",
+ max_lockdep_depth);
+#ifdef CONFIG_PROVE_LOCKING
+ seq_printf(m, " max bfs queue depth: %11u\n",
+ max_bfs_queue_depth);
+#endif
+ lockdep_stats_debug_show(m);
+ seq_printf(m, " debug_locks: %11u\n",
+ debug_locks);
+
+ return 0;
+}
+
+#ifdef CONFIG_LOCK_STAT
+
+struct lock_stat_data {
+ struct lock_class *class;
+ struct lock_class_stats stats;
+};
+
+struct lock_stat_seq {
+ struct lock_stat_data *iter_end;
+ struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
+};
+
+/*
+ * sort on absolute number of contentions
+ */
+static int lock_stat_cmp(const void *l, const void *r)
+{
+ const struct lock_stat_data *dl = l, *dr = r;
+ unsigned long nl, nr;
+
+ nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
+ nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
+
+ return nr - nl;
+}
+
+static void seq_line(struct seq_file *m, char c, int offset, int length)
+{
+ int i;
+
+ for (i = 0; i < offset; i++)
+ seq_puts(m, " ");
+ for (i = 0; i < length; i++)
+ seq_printf(m, "%c", c);
+ seq_puts(m, "\n");
+}
+
+static void snprint_time(char *buf, size_t bufsiz, s64 nr)
+{
+ s64 div;
+ s32 rem;
+
+ nr += 5; /* for display rounding */
+ div = div_s64_rem(nr, 1000, &rem);
+ snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
+}
+
+static void seq_time(struct seq_file *m, s64 time)
+{
+ char num[15];
+
+ snprint_time(num, sizeof(num), time);
+ seq_printf(m, " %14s", num);
+}
+
+static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
+{
+ seq_printf(m, "%14lu", lt->nr);
+ seq_time(m, lt->min);
+ seq_time(m, lt->max);
+ seq_time(m, lt->total);
+ seq_time(m, lt->nr ? div_s64(lt->total, lt->nr) : 0);
+}
+
+static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
+{
+ struct lockdep_subclass_key *ckey;
+ struct lock_class_stats *stats;
+ struct lock_class *class;
+ const char *cname;
+ int i, namelen;
+ char name[39];
+
+ class = data->class;
+ stats = &data->stats;
+
+ namelen = 38;
+ if (class->name_version > 1)
+ namelen -= 2; /* XXX truncates versions > 9 */
+ if (class->subclass)
+ namelen -= 2;
+
+ rcu_read_lock_sched();
+ cname = rcu_dereference_sched(class->name);
+ ckey = rcu_dereference_sched(class->key);
+
+ if (!cname && !ckey) {
+ rcu_read_unlock_sched();
+ return;
+
+ } else if (!cname) {
+ char str[KSYM_NAME_LEN];
+ const char *key_name;
+
+ key_name = __get_key_name(ckey, str);
+ snprintf(name, namelen, "%s", key_name);
+ } else {
+ snprintf(name, namelen, "%s", cname);
+ }
+ rcu_read_unlock_sched();
+
+ namelen = strlen(name);
+ if (class->name_version > 1) {
+ snprintf(name+namelen, 3, "#%d", class->name_version);
+ namelen += 2;
+ }
+ if (class->subclass) {
+ snprintf(name+namelen, 3, "/%d", class->subclass);
+ namelen += 2;
+ }
+
+ if (stats->write_holdtime.nr) {
+ if (stats->read_holdtime.nr)
+ seq_printf(m, "%38s-W:", name);
+ else
+ seq_printf(m, "%40s:", name);
+
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
+ seq_lock_time(m, &stats->write_waittime);
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
+ seq_lock_time(m, &stats->write_holdtime);
+ seq_puts(m, "\n");
+ }
+
+ if (stats->read_holdtime.nr) {
+ seq_printf(m, "%38s-R:", name);
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
+ seq_lock_time(m, &stats->read_waittime);
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
+ seq_lock_time(m, &stats->read_holdtime);
+ seq_puts(m, "\n");
+ }
+
+ if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
+ return;
+
+ if (stats->read_holdtime.nr)
+ namelen += 2;
+
+ for (i = 0; i < LOCKSTAT_POINTS; i++) {
+ char ip[32];
+
+ if (class->contention_point[i] == 0)
+ break;
+
+ if (!i)
+ seq_line(m, '-', 40-namelen, namelen);
+
+ snprintf(ip, sizeof(ip), "[<%p>]",
+ (void *)class->contention_point[i]);
+ seq_printf(m, "%40s %14lu %29s %pS\n",
+ name, stats->contention_point[i],
+ ip, (void *)class->contention_point[i]);
+ }
+ for (i = 0; i < LOCKSTAT_POINTS; i++) {
+ char ip[32];
+
+ if (class->contending_point[i] == 0)
+ break;
+
+ if (!i)
+ seq_line(m, '-', 40-namelen, namelen);
+
+ snprintf(ip, sizeof(ip), "[<%p>]",
+ (void *)class->contending_point[i]);
+ seq_printf(m, "%40s %14lu %29s %pS\n",
+ name, stats->contending_point[i],
+ ip, (void *)class->contending_point[i]);
+ }
+ if (i) {
+ seq_puts(m, "\n");
+ seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
+ seq_puts(m, "\n");
+ }
+}
+
+static void seq_header(struct seq_file *m)
+{
+ seq_puts(m, "lock_stat version 0.4\n");
+
+ if (unlikely(!debug_locks))
+ seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
+
+ seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
+ seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
+ "%14s %14s\n",
+ "class name",
+ "con-bounces",
+ "contentions",
+ "waittime-min",
+ "waittime-max",
+ "waittime-total",
+ "waittime-avg",
+ "acq-bounces",
+ "acquisitions",
+ "holdtime-min",
+ "holdtime-max",
+ "holdtime-total",
+ "holdtime-avg");
+ seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
+ seq_printf(m, "\n");
+}
+
+static void *ls_start(struct seq_file *m, loff_t *pos)
+{
+ struct lock_stat_seq *data = m->private;
+ struct lock_stat_data *iter;
+
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ iter = data->stats + (*pos - 1);
+ if (iter >= data->iter_end)
+ iter = NULL;
+
+ return iter;
+}
+
+static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ (*pos)++;
+ return ls_start(m, pos);
+}
+
+static void ls_stop(struct seq_file *m, void *v)
+{
+}
+
+static int ls_show(struct seq_file *m, void *v)
+{
+ if (v == SEQ_START_TOKEN)
+ seq_header(m);
+ else
+ seq_stats(m, v);
+
+ return 0;
+}
+
+static const struct seq_operations lockstat_ops = {
+ .start = ls_start,
+ .next = ls_next,
+ .stop = ls_stop,
+ .show = ls_show,
+};
+
+static int lock_stat_open(struct inode *inode, struct file *file)
+{
+ int res;
+ struct lock_class *class;
+ struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
+
+ if (!data)
+ return -ENOMEM;
+
+ res = seq_open(file, &lockstat_ops);
+ if (!res) {
+ struct lock_stat_data *iter = data->stats;
+ struct seq_file *m = file->private_data;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ iter->class = class;
+ iter->stats = lock_stats(class);
+ iter++;
+ }
+ data->iter_end = iter;
+
+ sort(data->stats, data->iter_end - data->stats,
+ sizeof(struct lock_stat_data),
+ lock_stat_cmp, NULL);
+
+ m->private = data;
+ } else
+ vfree(data);
+
+ return res;
+}
+
+static ssize_t lock_stat_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct lock_class *class;
+ char c;
+
+ if (count) {
+ if (get_user(c, buf))
+ return -EFAULT;
+
+ if (c != '0')
+ return count;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry)
+ clear_lock_stats(class);
+ }
+ return count;
+}
+
+static int lock_stat_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+
+ vfree(seq->private);
+ return seq_release(inode, file);
+}
+
+static const struct file_operations proc_lock_stat_operations = {
+ .open = lock_stat_open,
+ .write = lock_stat_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = lock_stat_release,
+};
+#endif /* CONFIG_LOCK_STAT */
+
+static int __init lockdep_proc_init(void)
+{
+ proc_create_seq("lockdep", S_IRUSR, NULL, &lockdep_ops);
+#ifdef CONFIG_PROVE_LOCKING
+ proc_create_seq("lockdep_chains", S_IRUSR, NULL, &lockdep_chains_ops);
+#endif
+ proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show);
+#ifdef CONFIG_LOCK_STAT
+ proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
+ &proc_lock_stat_operations);
+#endif
+
+ return 0;
+}
+
+__initcall(lockdep_proc_init);
+