diff options
Diffstat (limited to 'kernel/lockdep.c')
| -rw-r--r-- | kernel/lockdep.c | 53 |
1 files changed, 43 insertions, 10 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 24f176c9fc9f..8889f7dd7c46 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -431,6 +431,7 @@ unsigned int max_lockdep_depth; * 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), @@ -564,11 +565,12 @@ static void lockdep_print_held_locks(struct task_struct *curr) } } -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) @@ -652,6 +654,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) if (unlikely(!lockdep_initialized)) { lockdep_init(); lockdep_init_error = 1; + lock_init_error = lock->name; save_stack_trace(&lockdep_init_trace); } #endif @@ -719,7 +722,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) class = look_up_lock_class(lock, subclass); if (likely(class)) - return class; + goto out_set_class_cache; /* * Debug-check: all keys must be persistent! @@ -804,6 +807,7 @@ out_unlock_set: 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) @@ -1145,7 +1149,7 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth, 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)); @@ -1484,7 +1488,7 @@ print_bad_irq_dependency(struct task_struct *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), @@ -1713,7 +1717,7 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, 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)); @@ -2220,7 +2224,7 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this, printk("\n"); printk("=================================\n"); printk("[ INFO: inconsistent lock state ]\n"); - print_kernel_version(); + print_kernel_ident(); printk("---------------------------------\n"); printk("inconsistent {%s} -> {%s} usage.\n", @@ -2285,7 +2289,7 @@ print_irq_inversion_bug(struct task_struct *curr, 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)); @@ -3171,6 +3175,7 @@ print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, 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)); @@ -3615,6 +3620,7 @@ print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, 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)); @@ -3970,7 +3976,8 @@ void __init lockdep_info(void) #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); } @@ -3989,6 +3996,7 @@ print_freed_lock_bug(struct task_struct *curr, const void *mem_from, 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); @@ -4046,6 +4054,7 @@ static void print_held_locks_bug(struct task_struct *curr) 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)); @@ -4143,6 +4152,7 @@ void lockdep_sys_exit(void) 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); @@ -4162,10 +4172,33 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s) 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); + + /* + * 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(); |