diff options
Diffstat (limited to 'kernel/kprobes.c')
| -rw-r--r-- | kernel/kprobes.c | 91 |
1 files changed, 43 insertions, 48 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3897630d2335..f14ccd35e9b6 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -48,7 +48,7 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; -static DEFINE_SPINLOCK(kprobe_lock); /* Protects kprobe_table */ +static DECLARE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; @@ -167,7 +167,7 @@ static inline void reset_kprobe_instance(void) /* * This routine is called either: - * - under the kprobe_lock spinlock - during kprobe_[un]register() + * - under the kprobe_mutex - during kprobe_[un]register() * OR * - with preemption disabled - from arch/xxx/kernel/kprobes.c */ @@ -420,7 +420,6 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) /* * This is the second or subsequent kprobe at the address - handle * the intricacies - * TODO: Move kcalloc outside the spin_lock */ static int __kprobes register_aggr_kprobe(struct kprobe *old_p, struct kprobe *p) @@ -442,25 +441,6 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p, return ret; } -/* kprobe removal house-keeping routines */ -static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags) -{ - arch_disarm_kprobe(p); - hlist_del_rcu(&p->hlist); - spin_unlock_irqrestore(&kprobe_lock, flags); - arch_remove_kprobe(p); -} - -static inline void cleanup_aggr_kprobe(struct kprobe *old_p, - struct kprobe *p, unsigned long flags) -{ - list_del_rcu(&p->list); - if (list_empty(&old_p->list)) - cleanup_kprobe(old_p, flags); - else - spin_unlock_irqrestore(&kprobe_lock, flags); -} - static int __kprobes in_kprobes_functions(unsigned long addr) { if (addr >= (unsigned long)__kprobes_text_start @@ -472,7 +452,6 @@ static int __kprobes in_kprobes_functions(unsigned long addr) int __kprobes register_kprobe(struct kprobe *p) { int ret = 0; - unsigned long flags = 0; struct kprobe *old_p; struct module *mod; @@ -484,18 +463,17 @@ int __kprobes register_kprobe(struct kprobe *p) (unlikely(!try_module_get(mod)))) return -EINVAL; - if ((ret = arch_prepare_kprobe(p)) != 0) - goto rm_kprobe; - p->nmissed = 0; - spin_lock_irqsave(&kprobe_lock, flags); + down(&kprobe_mutex); old_p = get_kprobe(p->addr); if (old_p) { ret = register_aggr_kprobe(old_p, p); goto out; } - arch_copy_kprobe(p); + if ((ret = arch_prepare_kprobe(p)) != 0) + goto out; + INIT_HLIST_NODE(&p->hlist); hlist_add_head_rcu(&p->hlist, &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); @@ -503,10 +481,8 @@ int __kprobes register_kprobe(struct kprobe *p) arch_arm_kprobe(p); out: - spin_unlock_irqrestore(&kprobe_lock, flags); -rm_kprobe: - if (ret == -EEXIST) - arch_remove_kprobe(p); + up(&kprobe_mutex); + if (ret && mod) module_put(mod); return ret; @@ -514,29 +490,48 @@ rm_kprobe: void __kprobes unregister_kprobe(struct kprobe *p) { - unsigned long flags; - struct kprobe *old_p; struct module *mod; + struct kprobe *old_p, *cleanup_p; - spin_lock_irqsave(&kprobe_lock, flags); + down(&kprobe_mutex); old_p = get_kprobe(p->addr); - if (old_p) { - /* cleanup_*_kprobe() does the spin_unlock_irqrestore */ - if (old_p->pre_handler == aggr_pre_handler) - cleanup_aggr_kprobe(old_p, p, flags); - else - cleanup_kprobe(p, flags); + if (unlikely(!old_p)) { + up(&kprobe_mutex); + return; + } - synchronize_sched(); + if ((old_p->pre_handler == aggr_pre_handler) && + (p->list.next == &old_p->list) && + (p->list.prev == &old_p->list)) { + /* Only one element in the aggregate list */ + arch_disarm_kprobe(p); + hlist_del_rcu(&old_p->hlist); + cleanup_p = old_p; + } else if (old_p == p) { + /* Only one kprobe element in the hash list */ + arch_disarm_kprobe(p); + hlist_del_rcu(&p->hlist); + cleanup_p = p; + } else { + list_del_rcu(&p->list); + cleanup_p = NULL; + } - if ((mod = module_text_address((unsigned long)p->addr))) - module_put(mod); + up(&kprobe_mutex); - if (old_p->pre_handler == aggr_pre_handler && - list_empty(&old_p->list)) + synchronize_sched(); + if ((mod = module_text_address((unsigned long)p->addr))) + module_put(mod); + + if (cleanup_p) { + if (cleanup_p->pre_handler == aggr_pre_handler) { + list_del_rcu(&p->list); kfree(old_p); - } else - spin_unlock_irqrestore(&kprobe_lock, flags); + } + down(&kprobe_mutex); + arch_remove_kprobe(p); + up(&kprobe_mutex); + } } static struct notifier_block kprobe_exceptions_nb = { |