#include <linux/stringify.h>
#include <linux/bitops.h>
#include <linux/gfp.h>
+#include <linux/kmemcheck.h>
#include <asm/sections.h>
static inline int graph_unlock(void)
{
- if (debug_locks && !arch_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--;
arch_spin_unlock(&lockdep_lock);
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;
}
* 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),
usage[i] = '\0';
}
-static int __print_lock_name(struct lock_class *class)
+static void __print_lock_name(struct lock_class *class)
{
char str[KSYM_NAME_LEN];
const char *name;
name = class->name;
- if (!name)
- name = __get_key_name(class->key, str);
-
- return printk("%s", name);
-}
-
-static void print_lock_name(struct lock_class *class)
-{
- char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS];
- 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_kernel_version(void)
+static void print_kernel_ident(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)
if (unlikely(!lockdep_initialized)) {
lockdep_init();
lockdep_init_error = 1;
+ lock_init_error = lock->name;
save_stack_trace(&lockdep_init_trace);
}
#endif
*/
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!
graph_unlock();
raw_local_irq_restore(flags);
+out_set_class_cache:
if (!subclass || force)
lock->class_cache[0] = class;
else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
lock->class_cache[subclass] = class;
+ /*
+ * Hash collision, did we smoke some? We found a class with a matching
+ * hash but the subclass -- which is hashed in -- didn't match.
+ */
if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
return NULL;
unsigned long nr;
nr = lock - list_entries;
- WARN_ON(nr >= nr_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;
}
unsigned long nr;
nr = lock - list_entries;
- WARN_ON(nr >= nr_list_entries);
+ WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
return lock->class->dep_gen_id == lockdep_dependency_gen_id;
}
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_src);
if (!debug_locks_off_graph_unlock())
return 0;
+ /*
+ * Breadth-first-search failed, graph got corrupted?
+ */
WARN(1, "lockdep bfs error:%d\n", ret);
return 0;
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,
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);
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 held_lock *hlock_curr, *hlock_next;
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;
/*
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,
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]);
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);
BUG_ON(usage_bit >= LOCK_USAGE_STATES);
- if (hlock_class(hlock)->key == &__lockdep_no_validate__)
+ if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys)
continue;
if (!mark_lock(curr, hlock, usage_bit))
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;
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
+ /*
+ * So we're supposed to get called after you mask local IRQs, but for
+ * some reason the hardware doesn't quite think you did a proper job.
+ */
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return;
if (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 (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->softirq_disable_ip = ip;
curr->softirq_disable_event = ++curr->irq_events;
debug_atomic_inc(softirqs_off_events);
+ /*
+ * Whoops, we wanted softirqs off, so why aren't they?
+ */
DEBUG_LOCKS_WARN_ON(!softirq_count());
} else
debug_atomic_inc(redundant_softirqs_off);
if (!(gfp_mask & __GFP_FS))
return;
+ /*
+ * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
+ */
if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
return;
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:
{
int i;
+ kmemcheck_mark_initialized(lock, sizeof(*lock));
+
for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
lock->class_cache[i] = NULL;
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 (!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;
}
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;
* 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;
}
hlock = curr->held_locks + depth;
+ /*
+ * Plain impossible, we just registered it and checked it weren't no
+ * NULL like.. I bet this mushroom I ate was good!
+ */
if (DEBUG_LOCKS_WARN_ON(!class))
return 0;
hlock->class_idx = class_idx;
* 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;
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;
if (!class)
class = look_up_lock_class(lock, 0);
- if (DEBUG_LOCKS_WARN_ON(!class))
+ /*
+ * 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;
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;
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;
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;
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 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)
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;
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;
match |= class == lock->class_cache[j];
if (unlikely(match)) {
- if (debug_locks_off_graph_unlock())
+ if (debug_locks_off_graph_unlock()) {
+ /*
+ * We all just reset everything, how did it match?
+ */
WARN_ON(1);
+ }
goto out_restore;
}
}
#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);
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_dereference(const char *file, const int line)
+void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
{
struct task_struct *curr = current;
return;
#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
/* Note: the following can be executed concurrently, so be careful. */
- printk("\n===================================================\n");
- printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n");
- printk( "---------------------------------------------------\n");
- printk("%s:%d invoked rcu_dereference_check() without protection!\n",
- file, line);
+ 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("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks);
+ 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_dereference);
+EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
projects / linux-flexiantxendom0-3.2.10.git / blobdiff