#include <linux/utsname.h>
#include <linux/hash.h>
#include <linux/ftrace.h>
-
+#include <linux/stringify.h>
+#include <linux/bitops.h>
#include <asm/sections.h>
#include "lockdep_internals.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/lockdep.h>
+
#ifdef CONFIG_PROVE_LOCKING
int prove_locking = 1;
module_param(prove_locking, int, 0644);
static int lockdep_initialized;
unsigned long nr_list_entries;
-static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
+struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
/*
* All data structures here are protected by the global debug_lock.
atomic_t nr_find_usage_forwards_recursions;
atomic_t nr_find_usage_backwards_checks;
atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr) atomic_inc(ptr)
-# define debug_atomic_dec(ptr) atomic_dec(ptr)
-# define debug_atomic_read(ptr) atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr) do { } while (0)
-# define debug_atomic_dec(ptr) do { } while (0)
-# define debug_atomic_read(ptr) 0
#endif
/*
* Locking printouts:
*/
-#define __STR(foo) #foo
-#define STR(foo) __STR(foo)
-
#define __USAGE(__STATE) \
- [LOCK_USED_IN_##__STATE] = "IN-"STR(__STATE)"-W", \
- [LOCK_ENABLED_##__STATE] = STR(__STATE)"-ON-W", \
- [LOCK_USED_IN_##__STATE##_READ] = "IN-"STR(__STATE)"-R", \
- [LOCK_ENABLED_##__STATE##_READ] = STR(__STATE)"-ON-R",
+ [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
+ [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
+ [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
+ [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
static const char *usage_str[] =
{
return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
}
-void
-get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3,
- char *c4, char *c5, char *c6)
+static inline unsigned long lock_flag(enum lock_usage_bit bit)
{
- *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.', *c5 = '.', *c6 = '.';
-
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
- *c1 = '+';
- else
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
- *c1 = '-';
+ return 1UL << bit;
+}
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
- *c2 = '+';
- else
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
- *c2 = '-';
+static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
+{
+ char c = '.';
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
- *c3 = '-';
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) {
- *c3 = '+';
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
- *c3 = '?';
+ if (class->usage_mask & lock_flag(bit + 2))
+ c = '+';
+ if (class->usage_mask & lock_flag(bit)) {
+ c = '-';
+ if (class->usage_mask & lock_flag(bit + 2))
+ c = '?';
}
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
- *c4 = '-';
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) {
- *c4 = '+';
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
- *c4 = '?';
- }
+ return c;
+}
- if (class->usage_mask & LOCKF_USED_IN_RECLAIM_FS)
- *c5 = '+';
- else
- if (class->usage_mask & LOCKF_ENABLED_RECLAIM_FS)
- *c5 = '-';
+void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
+{
+ int i = 0;
- if (class->usage_mask & LOCKF_ENABLED_RECLAIM_FS_READ)
- *c6 = '-';
- if (class->usage_mask & LOCKF_USED_IN_RECLAIM_FS_READ) {
- *c6 = '+';
- if (class->usage_mask & LOCKF_ENABLED_RECLAIM_FS_READ)
- *c6 = '?';
- }
+#define LOCKDEP_STATE(__STATE) \
+ usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
+ usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+ usage[i] = '\0';
}
static void print_lock_name(struct lock_class *class)
{
- char str[KSYM_NAME_LEN], c1, c2, c3, c4, c5, c6;
+ char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS];
const char *name;
- get_usage_chars(class, &c1, &c2, &c3, &c4, &c5, &c6);
+ get_usage_chars(class, usage);
name = class->name;
if (!name) {
if (class->subclass)
printk("/%d", class->subclass);
}
- printk("){%c%c%c%c%c%c}", c1, c2, c3, c4, c5, c6);
+ printk("){%s}", usage);
}
static void print_lockdep_cache(struct lockdep_map *lock)
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 BFS generated tree\n", __func__);
+ break;
+ }
+
+ entry = get_lock_parent(entry);
+ depth--;
+ } while (entry && (depth >= 0));
+
+ return;
+}
/*
* printk all lock dependencies starting at <entry>:
*/
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++;
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++;
return 1;
}
+unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)];
+static struct circular_queue lock_cq;
+
+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)) {
+ 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;
+ }
+ }
+ }
+ }
+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;
* 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( "-------------------------------------------------------\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;
+ 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);
+
+ while (parent) {
+ print_circular_bug_entry(parent, --depth);
+ parent = get_lock_parent(parent);
+ }
printk("\nother info that might help us debug this:\n\n");
lockdep_print_held_locks(curr);
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);
+ WARN(1, "lockdep bfs error:%d\n", ret);
return 0;
}
* 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;
+
+
+#define BFS_PROCESS_RET(ret) do { \
+ if (ret < 0) \
+ return print_bfs_bug(ret); \
+ if (ret == 1) \
+ return 1; \
+ } while (0)
+
+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;
-
- if (lockdep_dependency_visit(source, depth))
- return 1;
-
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
+ int result;
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;
+ result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
+
+ 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;
-
- if (lockdep_dependency_visit(source, depth))
- return 1;
-
- if (!__raw_spin_is_locked(&lockdep_lock))
- return DEBUG_LOCKS_WARN_ON(1);
-
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
+ int result;
debug_atomic_inc(&nr_find_usage_backwards_checks);
- if (source->usage_mask & (1 << find_usage_bit)) {
- backwards_match = source;
- return 2;
- }
- if (!source && debug_locks_off_graph_unlock()) {
- WARN_ON(1);
- return 0;
- }
+ result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
- /*
- * Check this lock's dependency list:
- */
- 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;
- }
- return 1;
+ return result;
}
+
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,
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");
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)
- return ret;
-
- find_usage_bit = bit_forwards;
- ret = find_usage_forwards(hlock_class(next), 0);
- if (!ret || ret == 1)
- return ret;
- /* ret == 2 */
- return print_bad_irq_dependency(curr, prev, next,
+ this.class = hlock_class(prev);
+ ret = find_usage_backwards(&this, bit_backwards, &target_entry);
+ BFS_PROCESS_RET(ret);
+
+ that.parent = NULL;
+ that.class = hlock_class(next);
+ ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
+ BFS_PROCESS_RET(ret);
+
+ return print_bad_irq_dependency(curr, &this, &that,
+ target_entry, target_entry1,
+ prev, next,
bit_backwards, bit_forwards, irqclass);
}
-static int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
+static const char *state_names[] = {
+#define LOCKDEP_STATE(__STATE) \
+ __stringify(__STATE),
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static const char *state_rnames[] = {
+#define LOCKDEP_STATE(__STATE) \
+ __stringify(__STATE)"-READ",
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline const char *state_name(enum lock_usage_bit bit)
{
- /*
- * Prove that the new dependency does not connect a hardirq-safe
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
- LOCK_ENABLED_HARDIRQ, "hard"))
- return 0;
+ return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
+}
+static int exclusive_bit(int new_bit)
+{
/*
- * Prove that the new dependency does not connect a hardirq-safe-read
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
+ * USED_IN
+ * USED_IN_READ
+ * ENABLED
+ * ENABLED_READ
+ *
+ * bit 0 - write/read
+ * bit 1 - used_in/enabled
+ * bit 2+ state
*/
- if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
- LOCK_ENABLED_HARDIRQ, "hard-read"))
- return 0;
+
+ int state = new_bit & ~3;
+ int dir = new_bit & 2;
/*
- * Prove that the new dependency does not connect a softirq-safe
- * lock with a softirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
+ * keep state, bit flip the direction and strip read.
*/
- if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
- LOCK_ENABLED_SOFTIRQ, "soft"))
- return 0;
+ return state | (dir ^ 2);
+}
+
+static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next, enum lock_usage_bit bit)
+{
/*
- * Prove that the new dependency does not connect a softirq-safe-read
- * lock with a softirq-unsafe lock - to achieve this we search
+ * Prove that the new dependency does not connect a hardirq-safe
+ * lock with a hardirq-unsafe lock - to achieve this we search
* the backwards-subgraph starting at <prev>, and the
* forwards-subgraph starting at <next>:
*/
- if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
- LOCK_ENABLED_SOFTIRQ, "soft"))
+ if (!check_usage(curr, prev, next, bit,
+ exclusive_bit(bit), state_name(bit)))
return 0;
+ bit++; /* _READ */
+
/*
- * Prove that the new dependency does not connect a reclaim-fs-safe
- * lock with a reclaim-fs-unsafe lock - to achieve this we search
+ * Prove that the new dependency does not connect a hardirq-safe-read
+ * lock with a hardirq-unsafe lock - to achieve this we search
* the backwards-subgraph starting at <prev>, and the
* forwards-subgraph starting at <next>:
*/
- if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS,
- LOCK_ENABLED_RECLAIM_FS, "reclaim-fs"))
+ if (!check_usage(curr, prev, next, bit,
+ exclusive_bit(bit), state_name(bit)))
return 0;
- /*
- * Prove that the new dependency does not connect a reclaim-fs-safe-read
- * lock with a reclaim-fs-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS_READ,
- LOCK_ENABLED_RECLAIM_FS, "reclaim-fs-read"))
+ return 1;
+}
+
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+#define LOCKDEP_STATE(__STATE) \
+ if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
return 0;
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
return 1;
}
{
struct lock_list *entry;
int ret;
+ struct lock_list this;
+ struct lock_list *uninitialized_var(target_entry);
/*
* 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;
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++;
* 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)
{
curr->comm, task_pid_nr(curr));
print_lock(this);
if (forwards)
- printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
+ printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
else
- printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
- print_lock_name(other);
+ printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
+ print_lock_name(other->class);
printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
printk("\nother info that might help us debug this:\n");
lockdep_print_held_locks(curr);
- printk("\nthe first lock's dependencies:\n");
- print_lock_dependencies(hlock_class(this), 0);
-
- 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;
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
- find_usage_bit = bit;
- /* fills in <forwards_match> */
- ret = find_usage_forwards(hlock_class(this), 0);
- if (!ret || ret == 1)
- return ret;
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_forwards(&root, bit, &target_entry);
+ BFS_PROCESS_RET(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;
+ struct lock_list root;
+ struct lock_list *uninitialized_var(target_entry);
- find_usage_bit = bit;
- /* fills in <backwards_match> */
- ret = find_usage_backwards(hlock_class(this), 0);
- if (!ret || ret == 1)
- return ret;
+ root.parent = NULL;
+ root.class = hlock_class(this);
+ ret = find_usage_backwards(&root, bit, &target_entry);
+ BFS_PROCESS_RET(ret);
- return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
+ return print_irq_inversion_bug(curr, &root, target_entry,
+ this, 1, irqclass);
}
void print_irqtrace_events(struct task_struct *curr)
#define STRICT_READ_CHECKS 1
-static const char *state_names[] = {
-#define LOCKDEP_STATE(__STATE) \
- STR(__STATE),
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline const char *state_name(enum lock_usage_bit bit)
-{
- return state_names[bit >> 2];
-}
-
-static const char *state_rnames[] = {
-#define LOCKDEP_STATE(__STATE) \
- STR(__STATE)"-READ",
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline const char *state_rname(enum lock_usage_bit bit)
-{
- return state_rnames[bit >> 2];
-}
-
static int (*state_verbose_f[])(struct lock_class *class) = {
#define LOCKDEP_STATE(__STATE) \
__STATE##_verbose,
return state_verbose_f[bit >> 2](class);
}
-static int exclusive_bit(int new_bit)
-{
- /*
- * USED_IN
- * USED_IN_READ
- * ENABLED
- * ENABLED_READ
- *
- * bit 0 - write/read
- * bit 1 - used_in/enabled
- * bit 2+ state
- */
-
- int state = new_bit & ~3;
- int dir = new_bit & 2;
-
- return state | (dir ^ 2);
-}
-
typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
enum lock_usage_bit bit, const char *name);
static int
-mark_lock_irq_write(struct task_struct *curr, struct held_lock *this,
- int new_bit)
+mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
{
- const char *name = state_name(new_bit);
- const char *rname = state_rname(new_bit);
-
int excl_bit = exclusive_bit(new_bit);
+ int read = new_bit & 1;
int dir = new_bit & 2;
+ /*
+ * mark USED_IN has to look forwards -- to ensure no dependency
+ * has ENABLED state, which would allow recursion deadlocks.
+ *
+ * mark ENABLED has to look backwards -- to ensure no dependee
+ * has USED_IN state, which, again, would allow recursion deadlocks.
+ */
check_usage_f usage = dir ?
check_usage_backwards : check_usage_forwards;
+ /*
+ * Validate that this particular lock does not have conflicting
+ * usage states.
+ */
if (!valid_state(curr, this, new_bit, excl_bit))
return 0;
- if (!valid_state(curr, this, new_bit, excl_bit + 1))
- return 0;
/*
- * just marked it hardirq-safe, check that this lock
- * took no hardirq-unsafe lock in the past:
+ * Validate that the lock dependencies don't have conflicting usage
+ * states.
*/
- if (!usage(curr, this, excl_bit, name))
+ if ((!read || !dir || STRICT_READ_CHECKS) &&
+ !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
return 0;
-#if STRICT_READ_CHECKS
+
/*
- * just marked it hardirq-safe, check that this lock
- * took no hardirq-unsafe-read lock in the past:
+ * Check for read in write conflicts
*/
- if (!usage(curr, this, excl_bit + 1, rname))
- return 0;
-#endif
- if (state_verbose(new_bit, hlock_class(this)))
- return 2;
-
- return 1;
-}
-
-static int
-mark_lock_irq_read(struct task_struct *curr, struct held_lock *this,
- int new_bit)
-{
- const char *name = state_name(new_bit);
- const char *rname = state_rname(new_bit);
-
- int excl_bit = exclusive_bit(new_bit);
- int dir = new_bit & 2;
-
- if (!valid_state(curr, this, new_bit, excl_bit))
- return 0;
-
- if (!dir) {
- /*
- * just marked it hardirq-read-safe, check that this lock
- * took no hardirq-unsafe lock in the past:
- */
- if (!check_usage_forwards(curr, this, excl_bit, name))
+ if (!read) {
+ if (!valid_state(curr, this, new_bit, excl_bit + 1))
return 0;
- } else if (STRICT_READ_CHECKS) {
- /*
- * just marked it hardirq-read-unsafe, check that no
- * hardirq-safe lock in the system ever took it in the past:
- */
- if (!check_usage_backwards(curr, this, excl_bit, name))
+
+ if (STRICT_READ_CHECKS &&
+ !usage(curr, this, excl_bit + 1,
+ state_name(new_bit + 1)))
return 0;
}
return 1;
}
-static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- int ret = 1;
-
- switch(new_bit) {
- case LOCK_USED_IN_HARDIRQ:
- case LOCK_USED_IN_SOFTIRQ:
- case LOCK_USED_IN_RECLAIM_FS:
- case LOCK_ENABLED_HARDIRQ:
- case LOCK_ENABLED_SOFTIRQ:
- case LOCK_ENABLED_RECLAIM_FS:
- return mark_lock_irq_write(curr, this, new_bit);
-
- case LOCK_USED_IN_HARDIRQ_READ:
- case LOCK_USED_IN_SOFTIRQ_READ:
- case LOCK_USED_IN_RECLAIM_FS_READ:
- case LOCK_ENABLED_HARDIRQ_READ:
- case LOCK_ENABLED_SOFTIRQ_READ:
- case LOCK_ENABLED_RECLAIM_FS_READ:
- return mark_lock_irq_read(curr, this, new_bit);
-
- default:
- WARN_ON(1);
- break;
- }
-
- return ret;
-}
-
enum mark_type {
#define LOCKDEP_STATE(__STATE) __STATE,
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};
-#define MARK_HELD_CASE(__STATE) \
- case __STATE: \
- if (hlock->read) \
- usage_bit = LOCK_ENABLED_##__STATE##_READ; \
- else \
- usage_bit = LOCK_ENABLED_##__STATE; \
- break;
-
/*
* Mark all held locks with a usage bit:
*/
for (i = 0; i < curr->lockdep_depth; i++) {
hlock = curr->held_locks + i;
- switch (mark) {
-#define LOCKDEP_STATE(__STATE) MARK_HELD_CASE(__STATE)
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
- default:
- BUG();
- }
+ usage_bit = 2 + (mark << 2); /* ENABLED */
+ if (hlock->read)
+ usage_bit += 1; /* READ */
+
+ BUG_ON(usage_bit >= LOCK_USAGE_STATES);
if (!mark_lock(curr, hlock, usage_bit))
return 0;
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()))
+ 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;
}
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+}
+
#endif
/*
void lockdep_init_map(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass)
{
- if (unlikely(!debug_locks))
+ lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+ lock->cpu = raw_smp_processor_id();
+#endif
+
+ if (DEBUG_LOCKS_WARN_ON(!name)) {
+ lock->name = "NULL";
return;
+ }
+
+ lock->name = name;
if (DEBUG_LOCKS_WARN_ON(!key))
return;
- if (DEBUG_LOCKS_WARN_ON(!name))
- return;
/*
* Sanity check, the lock-class key must be persistent:
*/
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);
}
debug_locks_off();
printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return 0;
}
debug_locks_off();
printk("BUG: MAX_LOCK_DEPTH too low!\n");
printk("turning off the locking correctness validator.\n");
+ dump_stack();
return 0;
}
{
unsigned long flags;
+ trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
+
if (unlikely(current->lockdep_recursion))
return;
{
unsigned long flags;
+ trace_lock_release(lock, nested, ip);
+
if (unlikely(current->lockdep_recursion))
return;
hlock->holdtime_stamp = now;
}
+ trace_lock_acquired(lock, ip, waittime);
+
stats = get_lock_stats(hlock_class(hlock));
if (waittime) {
if (hlock->read)
{
unsigned long flags;
+ trace_lock_contended(lock, ip);
+
if (unlikely(!lock_stat))
return;
Code Review / linux-2.6.git / blobdiff