#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);
* to use a raw spinlock - we really dont want the spinlock
* code to recurse back into the lockdep code...
*/
-static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
static int graph_lock(void)
{
- __raw_spin_lock(&lockdep_lock);
+ 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
* dropped already)
*/
if (!debug_locks) {
- __raw_spin_unlock(&lockdep_lock);
+ arch_spin_unlock(&lockdep_lock);
return 0;
}
/* prevent any recursions within lockdep from causing deadlocks */
static inline int graph_unlock(void)
{
- if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
+ 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--;
- __raw_spin_unlock(&lockdep_lock);
+ arch_spin_unlock(&lockdep_lock);
return 0;
}
{
int ret = debug_locks_off();
- __raw_spin_unlock(&lockdep_lock);
+ arch_spin_unlock(&lockdep_lock);
return ret;
}
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;
}
}
#ifdef CONFIG_LOCK_STAT
-static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
+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)
{
return i;
}
-static void lock_time_inc(struct lock_time *lt, s64 time)
+static void lock_time_inc(struct lock_time *lt, u64 time)
{
if (time > lt->max)
lt->max = time;
- if (time < lt->min || !lt->min)
+ if (time < lt->min || !lt->nr)
lt->min = time;
lt->total += time;
static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
{
- dst->min += src->min;
- dst->max += src->max;
+ 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;
}
memset(&stats, 0, sizeof(struct lock_class_stats));
for_each_possible_cpu(cpu) {
struct lock_class_stats *pcs =
- &per_cpu(lock_stats, cpu)[class - lock_classes];
+ &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_each_possible_cpu(cpu) {
struct lock_class_stats *cpu_stats =
- &per_cpu(lock_stats, cpu)[class - lock_classes];
+ &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
memset(cpu_stats, 0, sizeof(struct lock_class_stats));
}
static struct lock_class_stats *get_lock_stats(struct lock_class *class)
{
- return &get_cpu_var(lock_stats)[class - lock_classes];
+ return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
}
static void put_lock_stats(struct lock_class_stats *stats)
{
- put_cpu_var(lock_stats);
+ put_cpu_var(cpu_lock_stats);
}
static void lock_release_holdtime(struct held_lock *hlock)
{
struct lock_class_stats *stats;
- s64 holdtime;
+ u64 holdtime;
if (!lock_stat)
return;
- holdtime = sched_clock() - hlock->holdtime_stamp;
+ holdtime = lockstat_clock() - hlock->holdtime_stamp;
stats = get_lock_stats(hlock_class(hlock));
if (hlock->read)
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) {
+ if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
if (!debug_locks_off_graph_unlock())
return 0;
unsigned int nr_softirq_chains;
unsigned int nr_process_chains;
unsigned int max_lockdep_depth;
-unsigned int max_recursion_depth;
-
-static unsigned int lockdep_dependency_gen_id;
-
-static bool lockdep_dependency_visit(struct lock_class *source,
- unsigned int depth)
-{
- if (!depth)
- lockdep_dependency_gen_id++;
- if (source->dep_gen_id == lockdep_dependency_gen_id)
- return true;
- source->dep_gen_id = lockdep_dependency_gen_id;
- return false;
-}
#ifdef CONFIG_DEBUG_LOCKDEP
/*
* 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),
/*
* Various lockdep statistics:
*/
-atomic_t chain_lookup_hits;
-atomic_t chain_lookup_misses;
-atomic_t hardirqs_on_events;
-atomic_t hardirqs_off_events;
-atomic_t redundant_hardirqs_on;
-atomic_t redundant_hardirqs_off;
-atomic_t softirqs_on_events;
-atomic_t softirqs_off_events;
-atomic_t redundant_softirqs_on;
-atomic_t redundant_softirqs_off;
-atomic_t nr_unused_locks;
-atomic_t nr_cyclic_checks;
-atomic_t nr_cyclic_check_recursions;
-atomic_t nr_find_usage_forwards_checks;
-atomic_t nr_find_usage_forwards_recursions;
-atomic_t nr_find_usage_backwards_checks;
-atomic_t nr_find_usage_backwards_recursions;
+DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
#endif
/*
usage[i] = '\0';
}
-static void print_lock_name(struct lock_class *class)
+static void __print_lock_name(struct lock_class *class)
{
- char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS];
+ char str[KSYM_NAME_LEN];
const char *name;
- get_usage_chars(class, usage);
-
name = class->name;
if (!name) {
name = __get_key_name(class->key, str);
- printk(" (%s", name);
+ printk("%s", name);
} else {
- printk(" (%s", name);
+ 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_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 all lock dependencies starting at <entry>:
- */
-static void __used
-print_lock_dependencies(struct lock_class *class, int depth)
+static void print_kernel_ident(void)
{
- struct lock_list *entry;
-
- if (lockdep_dependency_visit(class, depth))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(depth >= 20))
- return;
-
- print_lock_class_header(class, depth);
-
- list_for_each_entry(entry, &class->locks_after, entry) {
- if (DEBUG_LOCKS_WARN_ON(!entry->class))
- return;
-
- print_lock_dependencies(entry->class, depth + 1);
-
- printk("%*s ... acquired at:\n",depth,"");
- print_stack_trace(&entry->trace, 2);
- printk("\n");
- }
-}
-
-static void print_kernel_version(void)
-{
- printk("%s %.*s\n", init_utsname()->release,
+ printk("%s %.*s %s\n", init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
- init_utsname()->version);
+ init_utsname()->version,
+ print_tainted());
}
static int very_verbose(struct lock_class *class)
unsigned long start = (unsigned long) &_stext,
end = (unsigned long) &_end,
addr = (unsigned long) obj;
-#ifdef CONFIG_SMP
- int i;
-#endif
/*
* static variable?
if ((addr >= start) && (addr < end))
return 1;
-#ifdef CONFIG_SMP
+ if (arch_is_kernel_data(addr))
+ return 1;
+
/*
- * percpu var?
+ * in-kernel percpu var?
*/
- for_each_possible_cpu(i) {
- start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
- end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
- + per_cpu_offset(i);
-
- if ((addr >= start) && (addr < end))
- return 1;
- }
-#endif
+ if (is_kernel_percpu_address(addr))
+ return 1;
/*
- * module var?
+ * module static or percpu var?
*/
- return is_module_address(addr);
+ return is_module_address(addr) || is_module_percpu_address(addr);
}
/*
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:
*/
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;
}
class = look_up_lock_class(lock, subclass);
if (likely(class))
- return class;
+ goto out_set_class_cache;
/*
* Debug-check: all keys must be persistent!
printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return NULL;
}
class = lock_classes + nr_lock_classes++;
- debug_atomic_inc(&nr_unused_locks);
+ debug_atomic_inc(nr_unused_locks);
class->key = key;
class->name = lock->name;
class->subclass = subclass;
graph_unlock();
raw_local_irq_restore(flags);
+out_set_class_cache:
if (!subclass || force)
- lock->class_cache = class;
+ 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;
printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return NULL;
}
return list_entries + nr_list_entries++;
* Add a new dependency to the head of the list:
*/
static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
- struct list_head *head, unsigned long ip, int distance)
+ struct list_head *head, unsigned long ip,
+ int distance, struct stack_trace *trace)
{
struct lock_list *entry;
/*
if (!entry)
return 0;
- if (!save_trace(&entry->trace))
- 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
}
/*
+ * 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.
- *
- * (to keep the stackframe of the recursive functions small we
- * use these global variables, and we also mark various helper
- * functions as noinline.)
*/
-static struct held_lock *check_source, *check_target;
/*
* Print a dependency chain entry (this is only done when a deadlock
* has been detected):
*/
static noinline int
-print_circular_bug_entry(struct lock_list *target, unsigned int depth)
+print_circular_bug_entry(struct lock_list *target, int depth)
{
if (debug_locks_silent)
return 0;
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)
+print_circular_bug_header(struct lock_list *entry, unsigned int depth,
+ struct held_lock *check_src,
+ struct held_lock *check_tgt)
{
struct task_struct *curr = current;
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ if (debug_locks_silent)
return 0;
- printk("\n=======================================================\n");
- printk( "[ INFO: possible circular locking dependency detected ]\n");
- print_kernel_version();
- printk( "-------------------------------------------------------\n");
+ 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_source);
+ print_lock(check_src);
printk("\nbut task is already holding lock:\n");
- print_lock(check_target);
+ print_lock(check_tgt);
printk("\nwhich lock already depends on the new lock.\n\n");
printk("\nthe existing dependency chain (in reverse order) is:\n");
return 0;
}
-static noinline int print_circular_bug_tail(void)
+static inline int class_equal(struct lock_list *entry, void *data)
+{
+ return entry->class == data;
+}
+
+static noinline int print_circular_bug(struct lock_list *this,
+ struct lock_list *target,
+ struct held_lock *check_src,
+ struct held_lock *check_tgt)
{
struct task_struct *curr = current;
- struct lock_list this;
+ struct lock_list *parent;
+ struct lock_list *first_parent;
+ int depth;
- if (debug_locks_silent)
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;
- this.class = hlock_class(check_source);
- if (!save_trace(&this.trace))
+ if (!save_trace(&this->trace))
return 0;
- print_circular_bug_entry(&this, 0);
+ depth = get_lock_depth(target);
+
+ print_circular_bug_header(target, depth, check_src, check_tgt);
+
+ parent = get_lock_parent(target);
+ 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");
return 0;
}
-#define RECURSION_LIMIT 40
-
-static int noinline print_infinite_recursion_bug(void)
+static noinline int print_bfs_bug(int ret)
{
if (!debug_locks_off_graph_unlock())
return 0;
- WARN_ON(1);
+ /*
+ * Breadth-first-search failed, graph got corrupted?
+ */
+ WARN(1, "lockdep bfs error:%d\n", ret);
return 0;
}
-unsigned long __lockdep_count_forward_deps(struct lock_class *class,
- unsigned int depth)
+static int noop_count(struct lock_list *entry, void *data)
{
- struct lock_list *entry;
- unsigned long ret = 1;
+ (*(unsigned long *)data)++;
+ return 0;
+}
- if (lockdep_dependency_visit(class, depth))
- return 0;
+unsigned long __lockdep_count_forward_deps(struct lock_list *this)
+{
+ unsigned long count = 0;
+ struct lock_list *uninitialized_var(target_entry);
- /*
- * Recurse this class's dependency list:
- */
- list_for_each_entry(entry, &class->locks_after, entry)
- ret += __lockdep_count_forward_deps(entry->class, depth + 1);
+ __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
- return ret;
+ return count;
}
-
unsigned long lockdep_count_forward_deps(struct lock_class *class)
{
unsigned long ret, flags;
+ struct lock_list this;
+
+ this.parent = NULL;
+ this.class = class;
local_irq_save(flags);
- __raw_spin_lock(&lockdep_lock);
- ret = __lockdep_count_forward_deps(class, 0);
- __raw_spin_unlock(&lockdep_lock);
+ 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_class *class,
- unsigned int depth)
+unsigned long __lockdep_count_backward_deps(struct lock_list *this)
{
- struct lock_list *entry;
- unsigned long ret = 1;
+ unsigned long count = 0;
+ struct lock_list *uninitialized_var(target_entry);
- if (lockdep_dependency_visit(class, depth))
- return 0;
- /*
- * Recurse this class's dependency list:
- */
- list_for_each_entry(entry, &class->locks_before, entry)
- ret += __lockdep_count_backward_deps(entry->class, depth + 1);
+ __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
- return ret;
+ return count;
}
unsigned long lockdep_count_backward_deps(struct lock_class *class)
{
unsigned long ret, flags;
+ struct lock_list this;
+
+ this.parent = NULL;
+ this.class = class;
local_irq_save(flags);
- __raw_spin_lock(&lockdep_lock);
- ret = __lockdep_count_backward_deps(class, 0);
- __raw_spin_unlock(&lockdep_lock);
+ arch_spin_lock(&lockdep_lock);
+ ret = __lockdep_count_backward_deps(&this);
+ arch_spin_unlock(&lockdep_lock);
local_irq_restore(flags);
return ret;
* lead to <target>. Print an error and return 0 if it does.
*/
static noinline int
-check_noncircular(struct lock_class *source, unsigned int depth)
+check_noncircular(struct lock_list *root, struct lock_class *target,
+ struct lock_list **target_entry)
{
- struct lock_list *entry;
+ int result;
- if (lockdep_dependency_visit(source, depth))
- return 1;
+ debug_atomic_inc(nr_cyclic_checks);
- debug_atomic_inc(&nr_cyclic_check_recursions);
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_after, entry) {
- if (entry->class == hlock_class(check_target))
- return print_circular_bug_header(entry, depth+1);
- debug_atomic_inc(&nr_cyclic_checks);
- if (!check_noncircular(entry->class, depth+1))
- return print_circular_bug_entry(entry, depth+1);
- }
- return 1;
+ result = __bfs_forwards(root, target, class_equal, target_entry);
+
+ return result;
}
#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
* proving that two subgraphs can be connected by a new dependency
* without creating any illegal irq-safe -> irq-unsafe lock dependency.
*/
-static enum lock_usage_bit find_usage_bit;
-static struct lock_class *forwards_match, *backwards_match;
+
+static inline int usage_match(struct lock_list *entry, void *bit)
+{
+ return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
+}
+
+
/*
* Find a node in the forwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
+ * at @root->class that matches @bit.
*
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <forwards_match>.
+ * Return 0 if such a node exists in the subgraph, and put that node
+ * into *@target_entry.
*
- * Return 1 otherwise and keep <forwards_match> unchanged.
- * Return 0 on error.
+ * Return 1 otherwise and keep *@target_entry unchanged.
+ * Return <0 on error.
*/
-static noinline int
-find_usage_forwards(struct lock_class *source, unsigned int depth)
+static int
+find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
+ struct lock_list **target_entry)
{
- struct lock_list *entry;
- int ret;
+ int result;
- if (lockdep_dependency_visit(source, depth))
- return 1;
+ debug_atomic_inc(nr_find_usage_forwards_checks);
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
+ result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
- debug_atomic_inc(&nr_find_usage_forwards_checks);
- if (source->usage_mask & (1 << find_usage_bit)) {
- forwards_match = source;
- return 2;
- }
-
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_after, entry) {
- debug_atomic_inc(&nr_find_usage_forwards_recursions);
- ret = find_usage_forwards(entry->class, depth+1);
- if (ret == 2 || ret == 0)
- return ret;
- }
- return 1;
+ return result;
}
/*
* Find a node in the backwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
+ * at @root->class that matches @bit.
*
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <backwards_match>.
+ * Return 0 if such a node exists in the subgraph, and put that node
+ * into *@target_entry.
*
- * Return 1 otherwise and keep <backwards_match> unchanged.
- * Return 0 on error.
+ * Return 1 otherwise and keep *@target_entry unchanged.
+ * Return <0 on error.
*/
-static noinline int
-find_usage_backwards(struct lock_class *source, unsigned int depth)
+static int
+find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
+ struct lock_list **target_entry)
{
- struct lock_list *entry;
- int ret;
+ int result;
- if (lockdep_dependency_visit(source, depth))
- return 1;
+ debug_atomic_inc(nr_find_usage_backwards_checks);
- if (!__raw_spin_is_locked(&lockdep_lock))
- return DEBUG_LOCKS_WARN_ON(1);
+ result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
+ return result;
+}
- debug_atomic_inc(&nr_find_usage_backwards_checks);
- if (source->usage_mask & (1 << find_usage_bit)) {
- backwards_match = source;
- return 2;
- }
+static void print_lock_class_header(struct lock_class *class, int depth)
+{
+ int bit;
- if (!source && debug_locks_off_graph_unlock()) {
- WARN_ON(1);
- return 0;
+ 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;
/*
- * Check this lock's dependency list:
+ * 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.
*/
- list_for_each_entry(entry, &source->locks_before, entry) {
- debug_atomic_inc(&nr_find_usage_backwards_recursions);
- ret = find_usage_backwards(entry->class, depth+1);
- if (ret == 2 || ret == 0)
- return ret;
+ 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");
}
- return 1;
+
+ 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,
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;
- printk("\n======================================================\n");
- printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
+ printk("\n");
+ printk("======================================================\n");
+ printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
irqclass, irqclass);
- print_kernel_version();
- printk( "------------------------------------------------------\n");
+ 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,
printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
irqclass);
- print_lock_name(backwards_match);
+ print_lock_name(backwards_entry->class);
printk("\n... which became %s-irq-safe at:\n", irqclass);
- print_stack_trace(backwards_match->usage_traces + bit1, 1);
+ print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
printk("\nto a %s-irq-unsafe lock:\n", irqclass);
- print_lock_name(forwards_match);
+ print_lock_name(forwards_entry->class);
printk("\n... which became %s-irq-unsafe at:\n", irqclass);
printk("...");
- print_stack_trace(forwards_match->usage_traces + bit2, 1);
+ print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
printk("\nother info that might help us debug this:\n\n");
+ print_irq_lock_scenario(backwards_entry, forwards_entry,
+ hlock_class(prev), hlock_class(next));
+
lockdep_print_held_locks(curr);
- printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass);
- print_lock_dependencies(backwards_match, 0);
+ printk("\nthe dependencies between %s-irq-safe lock", irqclass);
+ printk(" and the holding lock:\n");
+ if (!save_trace(&prev_root->trace))
+ return 0;
+ print_shortest_lock_dependencies(backwards_entry, prev_root);
- printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass);
- print_lock_dependencies(forwards_match, 0);
+ printk("\nthe dependencies between the lock to be acquired");
+ printk(" and %s-irq-unsafe lock:\n", irqclass);
+ if (!save_trace(&next_root->trace))
+ return 0;
+ print_shortest_lock_dependencies(forwards_entry, next_root);
printk("\nstack backtrace:\n");
dump_stack();
enum lock_usage_bit bit_forwards, const char *irqclass)
{
int ret;
+ struct lock_list this, that;
+ struct lock_list *uninitialized_var(target_entry);
+ struct lock_list *uninitialized_var(target_entry1);
+
+ this.parent = NULL;
- find_usage_bit = bit_backwards;
- /* fills in <backwards_match> */
- ret = find_usage_backwards(hlock_class(prev), 0);
- if (!ret || ret == 1)
+ this.class = hlock_class(prev);
+ ret = find_usage_backwards(&this, bit_backwards, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- find_usage_bit = bit_forwards;
- ret = find_usage_forwards(hlock_class(next), 0);
- if (!ret || ret == 1)
+ that.parent = NULL;
+ that.class = hlock_class(next);
+ ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- /* ret == 2 */
- return print_bad_irq_dependency(curr, prev, next,
+
+ return print_bad_irq_dependency(curr, &this, &that,
+ target_entry, target_entry1,
+ prev, next,
bit_backwards, bit_forwards, irqclass);
}
#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=============================================\n");
- printk( "[ INFO: possible recursive locking detected ]\n");
- print_kernel_version();
- printk( "---------------------------------------------\n");
+ 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);
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");
*/
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance)
+ 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
* We are using global variables to control the recursion, to
* keep the stackframe size of the recursive functions low:
*/
- check_source = next;
- check_target = prev;
- if (!(check_noncircular(hlock_class(next), 0)))
- return print_circular_bug_tail();
+ 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;
}
}
+ 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);
+ 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);
+ next->acquire_ip, distance, &trace);
if (!ret)
return 0;
check_prevs_add(struct task_struct *curr, struct held_lock *next)
{
int depth = curr->lockdep_depth;
+ int trylock_loop = 0;
struct held_lock *hlock;
/*
* added:
*/
if (hlock->read != 2) {
- if (!check_prev_add(curr, hlock, next, distance))
+ if (!check_prev_add(curr, hlock, next,
+ distance, trylock_loop))
return 0;
/*
* Stop after the first non-trylock entry,
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;
struct list_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
struct held_lock *hlock_curr, *hlock_next;
- int i, j, n, cn;
+ 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;
/*
list_for_each_entry(chain, hash_head, entry) {
if (chain->chain_key == chain_key) {
cache_hit:
- debug_atomic_inc(&chain_lookup_hits);
+ debug_atomic_inc(chain_lookup_hits);
if (very_verbose(class))
printk("\nhash chain already cached, key: "
"%016Lx tail class: [%p] %s\n",
printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return 0;
}
chain = lock_chains + nr_lock_chains++;
}
i++;
chain->depth = curr->lockdep_depth + 1 - i;
- cn = nr_chain_hlocks;
- while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) {
- n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth);
- if (n == cn)
- break;
- cn = n;
- }
- if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
- chain->base = cn;
+ 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);
+ debug_atomic_inc(chain_lookup_misses);
inc_chains();
return 1;
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,
return;
}
id = hlock->class_idx - 1;
+ /*
+ * Whoops ran out of static storage again?
+ */
if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
return;
}
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,
#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=================================\n");
- printk( "[ INFO: inconsistent lock state ]\n");
- print_kernel_version();
- printk( "---------------------------------\n");
+ 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]);
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");
* print irq inversion bug:
*/
static int
-print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
+print_irq_inversion_bug(struct task_struct *curr,
+ struct lock_list *root, struct lock_list *other,
struct held_lock *this, int forwards,
const char *irqclass)
{
+ 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=========================================================\n");
- printk( "[ INFO: possible irq lock inversion dependency detected ]\n");
- print_kernel_version();
- printk( "---------------------------------------------------------\n");
+ 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);
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);
+ print_lock_name(other->class);
printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
- printk("\nthe first lock's dependencies:\n");
- print_lock_dependencies(hlock_class(this), 0);
+ /* 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 second lock's dependencies:\n");
- print_lock_dependencies(other, 0);
+ printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
+ if (!save_trace(&root->trace))
+ return 0;
+ print_shortest_lock_dependencies(other, root);
printk("\nstack backtrace:\n");
dump_stack();
enum lock_usage_bit bit, const char *irqclass)
{
int ret;
-
- find_usage_bit = bit;
- /* fills in <forwards_match> */
- ret = find_usage_forwards(hlock_class(this), 0);
- if (!ret || ret == 1)
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
+
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_forwards(&root, bit, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass);
+ return print_irq_inversion_bug(curr, &root, target_entry,
+ this, 1, irqclass);
}
/*
enum lock_usage_bit bit, const char *irqclass)
{
int ret;
-
- find_usage_bit = bit;
- /* fills in <backwards_match> */
- ret = find_usage_backwards(hlock_class(this), 0);
- if (!ret || ret == 1)
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
+
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_backwards(&root, bit, &target_entry);
+ if (ret < 0)
+ return print_bfs_bug(ret);
+ if (ret == 1)
return ret;
- return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
+ return print_irq_inversion_bug(curr, &root, target_entry,
+ this, 0, irqclass);
}
void print_irqtrace_events(struct task_struct *curr)
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;
}
}
/*
- * Debugging helper: via this flag we know that we are in
- * 'early bootup code', and will warn about any invalid irqs-on event:
- */
-static int early_boot_irqs_enabled;
-
-void early_boot_irqs_off(void)
-{
- early_boot_irqs_enabled = 0;
-}
-
-void early_boot_irqs_on(void)
-{
- early_boot_irqs_enabled = 1;
-}
-
-/*
* Hardirqs will be enabled:
*/
-void trace_hardirqs_on_caller(unsigned long ip)
+static void __trace_hardirqs_on_caller(unsigned long ip)
{
struct task_struct *curr = current;
- time_hardirqs_on(CALLER_ADDR0, ip);
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
- return;
-
- if (unlikely(curr->hardirqs_enabled)) {
- debug_atomic_inc(&redundant_hardirqs_on);
- return;
- }
/* we'll do an OFF -> ON transition: */
curr->hardirqs_enabled = 1;
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
- if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
- return;
/*
* We are going to turn hardirqs on, so set the
* usage bit for all held locks:
curr->hardirq_enable_ip = ip;
curr->hardirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(&hardirqs_on_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);
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;
curr->hardirqs_enabled = 0;
curr->hardirq_disable_ip = ip;
curr->hardirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(&hardirqs_off_events);
+ debug_atomic_inc(hardirqs_off_events);
} else
- debug_atomic_inc(&redundant_hardirqs_off);
+ debug_atomic_inc(redundant_hardirqs_off);
}
EXPORT_SYMBOL(trace_hardirqs_off_caller);
{
struct task_struct *curr = current;
- if (unlikely(!debug_locks))
+ 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);
+ 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);
+ 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
*/
if (curr->hardirqs_enabled)
mark_held_locks(curr, SOFTIRQ);
+ current->lockdep_recursion = 0;
}
/*
{
struct task_struct *curr = current;
- if (unlikely(!debug_locks))
+ 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;
curr->softirqs_enabled = 0;
curr->softirq_disable_ip = ip;
curr->softirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(&softirqs_off_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);
+ debug_atomic_inc(redundant_softirqs_off);
}
-void lockdep_trace_alloc(gfp_t gfp_mask)
+static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
{
struct task_struct *curr = current;
if (!(gfp_mask & __GFP_FS))
return;
- if (DEBUG_LOCKS_WARN_ON(irqs_disabled()))
+ /*
+ * 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)
{
/*
return 0;
}
-#else
+#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);
+ WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
return 1;
}
{
}
-#endif
+#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
/*
* Mark a lock with a usage bit, and validate the state transition:
if (!graph_lock())
return 0;
/*
- * Make sure we didnt race:
+ * Make sure we didn't race:
*/
if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
graph_unlock();
return 0;
break;
case LOCK_USED:
- debug_atomic_dec(&nr_unused_locks);
+ debug_atomic_dec(nr_unused_locks);
break;
default:
if (!debug_locks_off_graph_unlock())
void lockdep_init_map(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass)
{
- if (unlikely(!debug_locks))
+ 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;
- if (DEBUG_LOCKS_WARN_ON(!name))
- 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->name = name;
lock->key = key;
- lock->class_cache = NULL;
-#ifdef CONFIG_LOCK_STAT
- lock->cpu = raw_smp_processor_id();
-#endif
+
+ 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__;
+
/*
* 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)
+ 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)
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 (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
- debug_locks_off();
- printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
- printk("turning off the locking correctness validator.\n");
- return 0;
- }
+ if (lock->key == &__lockdep_no_validate__)
+ check = 1;
- if (!subclass)
- class = lock->class_cache;
+ if (subclass < NR_LOCKDEP_CACHING_CLASSES)
+ class = lock->class_cache[subclass];
/*
- * Not cached yet or subclass?
+ * Not cached?
*/
if (unlikely(!class)) {
class = register_lock_class(lock, subclass, 0);
if (!class)
return 0;
}
- debug_atomic_inc((atomic_t *)&class->ops);
+ atomic_inc((atomic_t *)&class->ops);
if (very_verbose(class)) {
printk("\nacquire class [%p] %s", class->key, class->name);
if (class->name_version > 1)
* 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 - lock_classes + 1;
+ hlock->class_idx = class_idx;
hlock->acquire_ip = ip;
hlock->instance = lock;
hlock->nest_lock = nest_lock;
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 = sched_clock();
+ hlock->holdtime_stamp = lockstat_clock();
#endif
if (check == 2 && !mark_irqflags(curr, hlock))
* 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;
debug_locks_off();
printk("BUG: MAX_LOCK_DEPTH too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return 0;
}
if (debug_locks_silent)
return 0;
- printk("\n=====================================\n");
- printk( "[ BUG: bad unlock balance detected! ]\n");
- printk( "-------------------------------------\n");
+ printk("\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);
{
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;
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,
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;
*/
if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
break;
- if (hlock->instance == lock)
+ if (match_held_lock(hlock, lock))
goto found_it;
prev_hlock = hlock;
}
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->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;
* 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;
*/
if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
break;
- if (hlock->instance == lock)
+ if (match_held_lock(hlock, lock))
goto found_it;
prev_hlock = hlock;
}
return print_unlock_inbalance_bug(curr, lock, ip);
found_it:
- lock_release_holdtime(hlock);
+ 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;
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->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;
/*
* Is the unlock non-nested:
*/
- if (hlock->instance != lock)
+ if (hlock->instance != lock || hlock->references)
return lock_release_non_nested(curr, lock, ip);
curr->lockdep_depth--;
+ /*
+ * 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;
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:
*/
* check if not in hardirq contexts:
*/
if (!hardirq_count()) {
- if (softirq_count())
+ if (softirq_count()) {
+ /* like the above, but with softirqs */
DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
- else
+ } else {
+ /* lick the above, does it taste good? */
DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
+ }
}
if (!debug_locks)
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);
+ irqs_disabled_flags(flags), nest_lock, ip, 0);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
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;
if (debug_locks_silent)
return 0;
- printk("\n=================================\n");
- printk( "[ BUG: bad contention detected! ]\n");
- printk( "---------------------------------\n");
+ 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);
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;
*/
if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
break;
- if (hlock->instance == lock)
+ if (match_held_lock(hlock, lock))
goto found_it;
prev_hlock = hlock;
}
return;
found_it:
- hlock->waittime_stamp = sched_clock();
+ 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,
struct held_lock *hlock, *prev_hlock;
struct lock_class_stats *stats;
unsigned int depth;
- u64 now;
- s64 waittime = 0;
+ 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;
*/
if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
break;
- if (hlock->instance == lock)
+ if (match_held_lock(hlock, lock))
goto found_it;
prev_hlock = hlock;
}
return;
found_it:
+ if (hlock->instance != lock)
+ return;
+
cpu = smp_processor_id();
if (hlock->waittime_stamp) {
- now = sched_clock();
+ 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)
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);
if (list_empty(head))
continue;
list_for_each_entry_safe(class, next, head, hash_entry) {
- if (unlikely(class == lock->class_cache)) {
- if (debug_locks_off_graph_unlock())
+ 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;
}
}
sizeof(struct list_head) * CLASSHASH_SIZE +
sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
- sizeof(struct list_head) * CHAINHASH_SIZE) / 1024);
+ sizeof(struct list_head) * CHAINHASH_SIZE
+#ifdef CONFIG_PROVE_LOCKING
+ + sizeof(struct circular_queue)
+#endif
+ ) / 1024
+ );
printk(" per task-struct memory footprint: %lu bytes\n",
sizeof(struct held_lock) * MAX_LOCK_DEPTH);
#ifdef CONFIG_DEBUG_LOCKDEP
if (lockdep_init_error) {
- printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
+ 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);
}
if (debug_locks_silent)
return;
- printk("\n=========================\n");
- printk( "[ BUG: held lock freed! ]\n");
- printk( "-------------------------\n");
+ 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);
if (debug_locks_silent)
return;
- printk("\n=====================================\n");
- printk( "[ BUG: lock held at task exit time! ]\n");
- printk( "-------------------------------------\n");
+ printk("\n");
+ printk("=====================================\n");
+ printk("[ BUG: lock held at task exit time! ]\n");
+ print_kernel_ident();
+ printk("-------------------------------------\n");
printk("%s/%d is exiting with locks still held!\n",
curr->comm, task_pid_nr(curr));
lockdep_print_held_locks(curr);
* 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)
+void debug_show_held_locks(struct task_struct *task)
{
if (unlikely(!debug_locks)) {
printk("INFO: lockdep is turned off.\n");
}
lockdep_print_held_locks(task);
}
-EXPORT_SYMBOL_GPL(__debug_show_held_locks);
-
-void debug_show_held_locks(struct task_struct *task)
-{
- __debug_show_held_locks(task);
-}
EXPORT_SYMBOL_GPL(debug_show_held_locks);
void lockdep_sys_exit(void)
if (unlikely(curr->lockdep_depth)) {
if (!debug_locks_off())
return;
- printk("\n================================================\n");
- printk( "[ BUG: lock held when returning to user space! ]\n");
- printk( "------------------------------------------------\n");
+ printk("\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_cpu_idle()
+ ? "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_cpu_idle())
+ 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);
projects / linux-flexiantxendom0-3.2.10.git / blobdiff