* 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
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)
printk("\n");
printk("======================================================\n");
printk("[ INFO: possible circular locking dependency detected ]\n");
- print_kernel_version();
+ print_kernel_ident();
printk("-------------------------------------------------------\n");
printk("%s/%d is trying to acquire lock:\n",
curr->comm, task_pid_nr(curr));
printk("======================================================\n");
printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
irqclass, irqclass);
- print_kernel_version();
+ 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),
printk("\n");
printk("=============================================\n");
printk("[ INFO: possible recursive locking detected ]\n");
- print_kernel_version();
+ print_kernel_ident();
printk("---------------------------------------------\n");
printk("%s/%d is trying to acquire lock:\n",
curr->comm, task_pid_nr(curr));
printk("\n");
printk("=================================\n");
printk("[ INFO: inconsistent lock state ]\n");
- print_kernel_version();
+ print_kernel_ident();
printk("---------------------------------\n");
printk("inconsistent {%s} -> {%s} usage.\n",
printk("\n");
printk("=========================================================\n");
printk("[ INFO: possible irq lock inversion dependency detected ]\n");
- print_kernel_version();
+ print_kernel_ident();
printk("---------------------------------------------------------\n");
printk("%s/%d just changed the state of lock:\n",
curr->comm, task_pid_nr(curr));
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));
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));
#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);
}
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);
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));
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);
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();
projects / linux-flexiantxendom0-3.2.10.git / blobdiff