const: constify remaining file_operations
[safe/jmp/linux-2.6] / kernel / kprobes.c
index a1e233a..5240d75 100644 (file)
@@ -43,6 +43,7 @@
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
 #include <linux/kdebug.h>
+#include <linux/memory.h>
 
 #include <asm-generic/sections.h>
 #include <asm/cacheflush.h>
@@ -67,7 +68,7 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
 /* NOTE: change this value only with kprobe_mutex held */
-static bool kprobe_enabled;
+static bool kprobes_all_disarmed;
 
 static DEFINE_MUTEX(kprobe_mutex);     /* Protects kprobe_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
@@ -102,7 +103,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
 #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
 
 struct kprobe_insn_page {
-       struct hlist_node hlist;
+       struct list_head list;
        kprobe_opcode_t *insns;         /* Page of instruction slots */
        char slot_used[INSNS_PER_PAGE];
        int nused;
@@ -116,14 +117,14 @@ enum kprobe_slot_state {
 };
 
 static DEFINE_MUTEX(kprobe_insn_mutex);        /* Protects kprobe_insn_pages */
-static struct hlist_head kprobe_insn_pages;
+static LIST_HEAD(kprobe_insn_pages);
 static int kprobe_garbage_slots;
 static int collect_garbage_slots(void);
 
 static int __kprobes check_safety(void)
 {
        int ret = 0;
-#if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
+#if defined(CONFIG_PREEMPT) && defined(CONFIG_FREEZER)
        ret = freeze_processes();
        if (ret == 0) {
                struct task_struct *p, *q;
@@ -151,10 +152,9 @@ loop_end:
 static kprobe_opcode_t __kprobes *__get_insn_slot(void)
 {
        struct kprobe_insn_page *kip;
-       struct hlist_node *pos;
 
  retry:
-       hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
+       list_for_each_entry(kip, &kprobe_insn_pages, list) {
                if (kip->nused < INSNS_PER_PAGE) {
                        int i;
                        for (i = 0; i < INSNS_PER_PAGE; i++) {
@@ -188,8 +188,8 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(void)
                kfree(kip);
                return NULL;
        }
-       INIT_HLIST_NODE(&kip->hlist);
-       hlist_add_head(&kip->hlist, &kprobe_insn_pages);
+       INIT_LIST_HEAD(&kip->list);
+       list_add(&kip->list, &kprobe_insn_pages);
        memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
        kip->slot_used[0] = SLOT_USED;
        kip->nused = 1;
@@ -218,12 +218,8 @@ static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
                 * so as not to have to set it up again the
                 * next time somebody inserts a probe.
                 */
-               hlist_del(&kip->hlist);
-               if (hlist_empty(&kprobe_insn_pages)) {
-                       INIT_HLIST_NODE(&kip->hlist);
-                       hlist_add_head(&kip->hlist,
-                                      &kprobe_insn_pages);
-               } else {
+               if (!list_is_singular(&kprobe_insn_pages)) {
+                       list_del(&kip->list);
                        module_free(NULL, kip->insns);
                        kfree(kip);
                }
@@ -234,18 +230,13 @@ static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
 
 static int __kprobes collect_garbage_slots(void)
 {
-       struct kprobe_insn_page *kip;
-       struct hlist_node *pos, *next;
-       int safety;
+       struct kprobe_insn_page *kip, *next;
 
        /* Ensure no-one is preepmted on the garbages */
-       mutex_unlock(&kprobe_insn_mutex);
-       safety = check_safety();
-       mutex_lock(&kprobe_insn_mutex);
-       if (safety != 0)
+       if (check_safety())
                return -EAGAIN;
 
-       hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
+       list_for_each_entry_safe(kip, next, &kprobe_insn_pages, list) {
                int i;
                if (kip->ngarbage == 0)
                        continue;
@@ -263,19 +254,17 @@ static int __kprobes collect_garbage_slots(void)
 void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
 {
        struct kprobe_insn_page *kip;
-       struct hlist_node *pos;
 
        mutex_lock(&kprobe_insn_mutex);
-       hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
+       list_for_each_entry(kip, &kprobe_insn_pages, list) {
                if (kip->insns <= slot &&
                    slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
                        int i = (slot - kip->insns) / MAX_INSN_SIZE;
                        if (dirty) {
                                kip->slot_used[i] = SLOT_DIRTY;
                                kip->ngarbage++;
-                       } else {
+                       } else
                                collect_one_slot(kip, i);
-                       }
                        break;
                }
        }
@@ -318,6 +307,22 @@ struct kprobe __kprobes *get_kprobe(void *addr)
        return NULL;
 }
 
+/* Arm a kprobe with text_mutex */
+static void __kprobes arm_kprobe(struct kprobe *kp)
+{
+       mutex_lock(&text_mutex);
+       arch_arm_kprobe(kp);
+       mutex_unlock(&text_mutex);
+}
+
+/* Disarm a kprobe with text_mutex */
+static void __kprobes disarm_kprobe(struct kprobe *kp)
+{
+       mutex_lock(&text_mutex);
+       arch_disarm_kprobe(kp);
+       mutex_unlock(&text_mutex);
+}
+
 /*
  * Aggregate handlers for multiple kprobes support - these handlers
  * take care of invoking the individual kprobe handlers on p->list
@@ -327,7 +332,7 @@ static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
        struct kprobe *kp;
 
        list_for_each_entry_rcu(kp, &p->list, list) {
-               if (kp->pre_handler) {
+               if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
                        set_kprobe_instance(kp);
                        if (kp->pre_handler(kp, regs))
                                return 1;
@@ -343,7 +348,7 @@ static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
        struct kprobe *kp;
 
        list_for_each_entry_rcu(kp, &p->list, list) {
-               if (kp->post_handler) {
+               if (kp->post_handler && likely(!kprobe_disabled(kp))) {
                        set_kprobe_instance(kp);
                        kp->post_handler(kp, regs, flags);
                        reset_kprobe_instance();
@@ -517,20 +522,28 @@ static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
 }
 
 /*
-* Add the new probe to old_p->list. Fail if this is the
+* Add the new probe to ap->list. Fail if this is the
 * second jprobe at the address - two jprobes can't coexist
 */
-static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
+static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
 {
+       BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
        if (p->break_handler) {
-               if (old_p->break_handler)
+               if (ap->break_handler)
                        return -EEXIST;
-               list_add_tail_rcu(&p->list, &old_p->list);
-               old_p->break_handler = aggr_break_handler;
+               list_add_tail_rcu(&p->list, &ap->list);
+               ap->break_handler = aggr_break_handler;
        } else
-               list_add_rcu(&p->list, &old_p->list);
-       if (p->post_handler && !old_p->post_handler)
-               old_p->post_handler = aggr_post_handler;
+               list_add_rcu(&p->list, &ap->list);
+       if (p->post_handler && !ap->post_handler)
+               ap->post_handler = aggr_post_handler;
+
+       if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
+               ap->flags &= ~KPROBE_FLAG_DISABLED;
+               if (!kprobes_all_disarmed)
+                       /* Arm the breakpoint again. */
+                       arm_kprobe(ap);
+       }
        return 0;
 }
 
@@ -543,11 +556,13 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
        copy_kprobe(p, ap);
        flush_insn_slot(ap);
        ap->addr = p->addr;
+       ap->flags = p->flags;
        ap->pre_handler = aggr_pre_handler;
        ap->fault_handler = aggr_fault_handler;
-       if (p->post_handler)
+       /* We don't care the kprobe which has gone. */
+       if (p->post_handler && !kprobe_gone(p))
                ap->post_handler = aggr_post_handler;
-       if (p->break_handler)
+       if (p->break_handler && !kprobe_gone(p))
                ap->break_handler = aggr_break_handler;
 
        INIT_LIST_HEAD(&ap->list);
@@ -564,20 +579,59 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
                                          struct kprobe *p)
 {
        int ret = 0;
-       struct kprobe *ap;
+       struct kprobe *ap = old_p;
 
-       if (old_p->pre_handler == aggr_pre_handler) {
-               copy_kprobe(old_p, p);
-               ret = add_new_kprobe(old_p, p);
-       } else {
+       if (old_p->pre_handler != aggr_pre_handler) {
+               /* If old_p is not an aggr_probe, create new aggr_kprobe. */
                ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
                if (!ap)
                        return -ENOMEM;
                add_aggr_kprobe(ap, old_p);
-               copy_kprobe(ap, p);
-               ret = add_new_kprobe(ap, p);
        }
-       return ret;
+
+       if (kprobe_gone(ap)) {
+               /*
+                * Attempting to insert new probe at the same location that
+                * had a probe in the module vaddr area which already
+                * freed. So, the instruction slot has already been
+                * released. We need a new slot for the new probe.
+                */
+               ret = arch_prepare_kprobe(ap);
+               if (ret)
+                       /*
+                        * Even if fail to allocate new slot, don't need to
+                        * free aggr_probe. It will be used next time, or
+                        * freed by unregister_kprobe.
+                        */
+                       return ret;
+
+               /*
+                * Clear gone flag to prevent allocating new slot again, and
+                * set disabled flag because it is not armed yet.
+                */
+               ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
+                           | KPROBE_FLAG_DISABLED;
+       }
+
+       copy_kprobe(ap, p);
+       return add_new_kprobe(ap, p);
+}
+
+/* Try to disable aggr_kprobe, and return 1 if succeeded.*/
+static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p)
+{
+       struct kprobe *kp;
+
+       list_for_each_entry_rcu(kp, &p->list, list) {
+               if (!kprobe_disabled(kp))
+                       /*
+                        * There is an active probe on the list.
+                        * We can't disable aggr_kprobe.
+                        */
+                       return 0;
+       }
+       p->flags |= KPROBE_FLAG_DISABLED;
+       return 1;
 }
 
 static int __kprobes in_kprobes_functions(unsigned long addr)
@@ -619,8 +673,7 @@ static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
        return (kprobe_opcode_t *)(((char *)addr) + p->offset);
 }
 
-static int __kprobes __register_kprobe(struct kprobe *p,
-       unsigned long called_from)
+int __kprobes register_kprobe(struct kprobe *p)
 {
        int ret = 0;
        struct kprobe *old_p;
@@ -633,34 +686,38 @@ static int __kprobes __register_kprobe(struct kprobe *p,
        p->addr = addr;
 
        preempt_disable();
-       if (!__kernel_text_address((unsigned long) p->addr) ||
+       if (!kernel_text_address((unsigned long) p->addr) ||
            in_kprobes_functions((unsigned long) p->addr)) {
                preempt_enable();
                return -EINVAL;
        }
 
-       p->mod_refcounted = 0;
+       /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
+       p->flags &= KPROBE_FLAG_DISABLED;
 
        /*
         * Check if are we probing a module.
         */
        probed_mod = __module_text_address((unsigned long) p->addr);
        if (probed_mod) {
-               struct module *calling_mod;
-               calling_mod = __module_text_address(called_from);
                /*
-                * We must allow modules to probe themself and in this case
-                * avoid incrementing the module refcount, so as to allow
-                * unloading of self probing modules.
+                * We must hold a refcount of the probed module while updating
+                * its code to prohibit unexpected unloading.
                 */
-               if (calling_mod != probed_mod) {
-                       if (unlikely(!try_module_get(probed_mod))) {
-                               preempt_enable();
-                               return -EINVAL;
-                       }
-                       p->mod_refcounted = 1;
-               } else
-                       probed_mod = NULL;
+               if (unlikely(!try_module_get(probed_mod))) {
+                       preempt_enable();
+                       return -EINVAL;
+               }
+               /*
+                * If the module freed .init.text, we couldn't insert
+                * kprobes in there.
+                */
+               if (within_module_init((unsigned long)p->addr, probed_mod) &&
+                   probed_mod->state != MODULE_STATE_COMING) {
+                       module_put(probed_mod);
+                       preempt_enable();
+                       return -EINVAL;
+               }
        }
        preempt_enable();
 
@@ -673,59 +730,76 @@ static int __kprobes __register_kprobe(struct kprobe *p,
                goto out;
        }
 
+       mutex_lock(&text_mutex);
        ret = arch_prepare_kprobe(p);
        if (ret)
-               goto out;
+               goto out_unlock_text;
 
        INIT_HLIST_NODE(&p->hlist);
        hlist_add_head_rcu(&p->hlist,
                       &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
 
-       if (kprobe_enabled)
+       if (!kprobes_all_disarmed && !kprobe_disabled(p))
                arch_arm_kprobe(p);
 
+out_unlock_text:
+       mutex_unlock(&text_mutex);
 out:
        mutex_unlock(&kprobe_mutex);
 
-       if (ret && probed_mod)
+       if (probed_mod)
                module_put(probed_mod);
+
        return ret;
 }
+EXPORT_SYMBOL_GPL(register_kprobe);
 
-/*
- * Unregister a kprobe without a scheduler synchronization.
- */
-static int __kprobes __unregister_kprobe_top(struct kprobe *p)
+/* Check passed kprobe is valid and return kprobe in kprobe_table. */
+static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
 {
        struct kprobe *old_p, *list_p;
 
        old_p = get_kprobe(p->addr);
        if (unlikely(!old_p))
-               return -EINVAL;
+               return NULL;
 
        if (p != old_p) {
                list_for_each_entry_rcu(list_p, &old_p->list, list)
                        if (list_p == p)
                        /* kprobe p is a valid probe */
-                               goto valid_p;
-               return -EINVAL;
+                               goto valid;
+               return NULL;
        }
-valid_p:
+valid:
+       return old_p;
+}
+
+/*
+ * Unregister a kprobe without a scheduler synchronization.
+ */
+static int __kprobes __unregister_kprobe_top(struct kprobe *p)
+{
+       struct kprobe *old_p, *list_p;
+
+       old_p = __get_valid_kprobe(p);
+       if (old_p == NULL)
+               return -EINVAL;
+
        if (old_p == p ||
            (old_p->pre_handler == aggr_pre_handler &&
             list_is_singular(&old_p->list))) {
                /*
                 * Only probe on the hash list. Disarm only if kprobes are
-                * enabled - otherwise, the breakpoint would already have
-                * been removed. We save on flushing icache.
+                * enabled and not gone - otherwise, the breakpoint would
+                * already have been removed. We save on flushing icache.
                 */
-               if (kprobe_enabled)
-                       arch_disarm_kprobe(p);
+               if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
+                       disarm_kprobe(p);
                hlist_del_rcu(&old_p->hlist);
        } else {
-               if (p->break_handler)
+               if (p->break_handler && !kprobe_gone(p))
                        old_p->break_handler = NULL;
-               if (p->post_handler) {
+               if (p->post_handler && !kprobe_gone(p)) {
                        list_for_each_entry_rcu(list_p, &old_p->list, list) {
                                if ((list_p != p) && (list_p->post_handler))
                                        goto noclean;
@@ -734,45 +808,38 @@ valid_p:
                }
 noclean:
                list_del_rcu(&p->list);
+               if (!kprobe_disabled(old_p)) {
+                       try_to_disable_aggr_kprobe(old_p);
+                       if (!kprobes_all_disarmed && kprobe_disabled(old_p))
+                               disarm_kprobe(old_p);
+               }
        }
        return 0;
 }
 
 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
 {
-       struct module *mod;
        struct kprobe *old_p;
 
-       if (p->mod_refcounted) {
-               /*
-                * Since we've already incremented refcount,
-                * we don't need to disable preemption.
-                */
-               mod = module_text_address((unsigned long)p->addr);
-               if (mod)
-                       module_put(mod);
-       }
-
-       if (list_empty(&p->list) || list_is_singular(&p->list)) {
-               if (!list_empty(&p->list)) {
-                       /* "p" is the last child of an aggr_kprobe */
-                       old_p = list_entry(p->list.next, struct kprobe, list);
-                       list_del(&p->list);
-                       kfree(old_p);
-               }
+       if (list_empty(&p->list))
                arch_remove_kprobe(p);
+       else if (list_is_singular(&p->list)) {
+               /* "p" is the last child of an aggr_kprobe */
+               old_p = list_entry(p->list.next, struct kprobe, list);
+               list_del(&p->list);
+               arch_remove_kprobe(old_p);
+               kfree(old_p);
        }
 }
 
-static int __kprobes __register_kprobes(struct kprobe **kps, int num,
-       unsigned long called_from)
+int __kprobes register_kprobes(struct kprobe **kps, int num)
 {
        int i, ret = 0;
 
        if (num <= 0)
                return -EINVAL;
        for (i = 0; i < num; i++) {
-               ret = __register_kprobe(kps[i], called_from);
+               ret = register_kprobe(kps[i]);
                if (ret < 0) {
                        if (i > 0)
                                unregister_kprobes(kps, i);
@@ -781,26 +848,13 @@ static int __kprobes __register_kprobes(struct kprobe **kps, int num,
        }
        return ret;
 }
-
-/*
- * Registration and unregistration functions for kprobe.
- */
-int __kprobes register_kprobe(struct kprobe *p)
-{
-       return __register_kprobes(&p, 1,
-                                 (unsigned long)__builtin_return_address(0));
-}
+EXPORT_SYMBOL_GPL(register_kprobes);
 
 void __kprobes unregister_kprobe(struct kprobe *p)
 {
        unregister_kprobes(&p, 1);
 }
-
-int __kprobes register_kprobes(struct kprobe **kps, int num)
-{
-       return __register_kprobes(kps, num,
-                                 (unsigned long)__builtin_return_address(0));
-}
+EXPORT_SYMBOL_GPL(unregister_kprobe);
 
 void __kprobes unregister_kprobes(struct kprobe **kps, int num)
 {
@@ -819,6 +873,7 @@ void __kprobes unregister_kprobes(struct kprobe **kps, int num)
                if (kps[i]->addr)
                        __unregister_kprobe_bottom(kps[i]);
 }
+EXPORT_SYMBOL_GPL(unregister_kprobes);
 
 static struct notifier_block kprobe_exceptions_nb = {
        .notifier_call = kprobe_exceptions_notify,
@@ -830,8 +885,7 @@ unsigned long __weak arch_deref_entry_point(void *entry)
        return (unsigned long)entry;
 }
 
-static int __kprobes __register_jprobes(struct jprobe **jps, int num,
-       unsigned long called_from)
+int __kprobes register_jprobes(struct jprobe **jps, int num)
 {
        struct jprobe *jp;
        int ret = 0, i;
@@ -849,7 +903,7 @@ static int __kprobes __register_jprobes(struct jprobe **jps, int num,
                        /* Todo: Verify probepoint is a function entry point */
                        jp->kp.pre_handler = setjmp_pre_handler;
                        jp->kp.break_handler = longjmp_break_handler;
-                       ret = __register_kprobe(&jp->kp, called_from);
+                       ret = register_kprobe(&jp->kp);
                }
                if (ret < 0) {
                        if (i > 0)
@@ -859,23 +913,19 @@ static int __kprobes __register_jprobes(struct jprobe **jps, int num,
        }
        return ret;
 }
+EXPORT_SYMBOL_GPL(register_jprobes);
 
 int __kprobes register_jprobe(struct jprobe *jp)
 {
-       return __register_jprobes(&jp, 1,
-               (unsigned long)__builtin_return_address(0));
+       return register_jprobes(&jp, 1);
 }
+EXPORT_SYMBOL_GPL(register_jprobe);
 
 void __kprobes unregister_jprobe(struct jprobe *jp)
 {
        unregister_jprobes(&jp, 1);
 }
-
-int __kprobes register_jprobes(struct jprobe **jps, int num)
-{
-       return __register_jprobes(jps, num,
-               (unsigned long)__builtin_return_address(0));
-}
+EXPORT_SYMBOL_GPL(unregister_jprobe);
 
 void __kprobes unregister_jprobes(struct jprobe **jps, int num)
 {
@@ -895,6 +945,7 @@ void __kprobes unregister_jprobes(struct jprobe **jps, int num)
                        __unregister_kprobe_bottom(&jps[i]->kp);
        }
 }
+EXPORT_SYMBOL_GPL(unregister_jprobes);
 
 #ifdef CONFIG_KRETPROBES
 /*
@@ -920,10 +971,8 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
                ri->rp = rp;
                ri->task = current;
 
-               if (rp->entry_handler && rp->entry_handler(ri, regs)) {
-                       spin_unlock_irqrestore(&rp->lock, flags);
+               if (rp->entry_handler && rp->entry_handler(ri, regs))
                        return 0;
-               }
 
                arch_prepare_kretprobe(ri, regs);
 
@@ -939,8 +988,7 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
        return 0;
 }
 
-static int __kprobes __register_kretprobe(struct kretprobe *rp,
-                                         unsigned long called_from)
+int __kprobes register_kretprobe(struct kretprobe *rp)
 {
        int ret = 0;
        struct kretprobe_instance *inst;
@@ -986,21 +1034,21 @@ static int __kprobes __register_kretprobe(struct kretprobe *rp,
 
        rp->nmissed = 0;
        /* Establish function entry probe point */
-       ret = __register_kprobe(&rp->kp, called_from);
+       ret = register_kprobe(&rp->kp);
        if (ret != 0)
                free_rp_inst(rp);
        return ret;
 }
+EXPORT_SYMBOL_GPL(register_kretprobe);
 
-static int __kprobes __register_kretprobes(struct kretprobe **rps, int num,
-       unsigned long called_from)
+int __kprobes register_kretprobes(struct kretprobe **rps, int num)
 {
        int ret = 0, i;
 
        if (num <= 0)
                return -EINVAL;
        for (i = 0; i < num; i++) {
-               ret = __register_kretprobe(rps[i], called_from);
+               ret = register_kretprobe(rps[i]);
                if (ret < 0) {
                        if (i > 0)
                                unregister_kretprobes(rps, i);
@@ -1009,23 +1057,13 @@ static int __kprobes __register_kretprobes(struct kretprobe **rps, int num,
        }
        return ret;
 }
-
-int __kprobes register_kretprobe(struct kretprobe *rp)
-{
-       return __register_kretprobes(&rp, 1,
-                       (unsigned long)__builtin_return_address(0));
-}
+EXPORT_SYMBOL_GPL(register_kretprobes);
 
 void __kprobes unregister_kretprobe(struct kretprobe *rp)
 {
        unregister_kretprobes(&rp, 1);
 }
-
-int __kprobes register_kretprobes(struct kretprobe **rps, int num)
-{
-       return __register_kretprobes(rps, num,
-                       (unsigned long)__builtin_return_address(0));
-}
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
 
 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
 {
@@ -1047,24 +1085,30 @@ void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
                }
        }
 }
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
 
 #else /* CONFIG_KRETPROBES */
 int __kprobes register_kretprobe(struct kretprobe *rp)
 {
        return -ENOSYS;
 }
+EXPORT_SYMBOL_GPL(register_kretprobe);
 
 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
 {
        return -ENOSYS;
 }
+EXPORT_SYMBOL_GPL(register_kretprobes);
+
 void __kprobes unregister_kretprobe(struct kretprobe *rp)
 {
 }
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
 
 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
 {
 }
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
 
 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
                                           struct pt_regs *regs)
@@ -1074,6 +1118,73 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
 
 #endif /* CONFIG_KRETPROBES */
 
+/* Set the kprobe gone and remove its instruction buffer. */
+static void __kprobes kill_kprobe(struct kprobe *p)
+{
+       struct kprobe *kp;
+
+       p->flags |= KPROBE_FLAG_GONE;
+       if (p->pre_handler == aggr_pre_handler) {
+               /*
+                * If this is an aggr_kprobe, we have to list all the
+                * chained probes and mark them GONE.
+                */
+               list_for_each_entry_rcu(kp, &p->list, list)
+                       kp->flags |= KPROBE_FLAG_GONE;
+               p->post_handler = NULL;
+               p->break_handler = NULL;
+       }
+       /*
+        * Here, we can remove insn_slot safely, because no thread calls
+        * the original probed function (which will be freed soon) any more.
+        */
+       arch_remove_kprobe(p);
+}
+
+/* Module notifier call back, checking kprobes on the module */
+static int __kprobes kprobes_module_callback(struct notifier_block *nb,
+                                            unsigned long val, void *data)
+{
+       struct module *mod = data;
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct kprobe *p;
+       unsigned int i;
+       int checkcore = (val == MODULE_STATE_GOING);
+
+       if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
+               return NOTIFY_DONE;
+
+       /*
+        * When MODULE_STATE_GOING was notified, both of module .text and
+        * .init.text sections would be freed. When MODULE_STATE_LIVE was
+        * notified, only .init.text section would be freed. We need to
+        * disable kprobes which have been inserted in the sections.
+        */
+       mutex_lock(&kprobe_mutex);
+       for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+               head = &kprobe_table[i];
+               hlist_for_each_entry_rcu(p, node, head, hlist)
+                       if (within_module_init((unsigned long)p->addr, mod) ||
+                           (checkcore &&
+                            within_module_core((unsigned long)p->addr, mod))) {
+                               /*
+                                * The vaddr this probe is installed will soon
+                                * be vfreed buy not synced to disk. Hence,
+                                * disarming the breakpoint isn't needed.
+                                */
+                               kill_kprobe(p);
+                       }
+       }
+       mutex_unlock(&kprobe_mutex);
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block kprobe_module_nb = {
+       .notifier_call = kprobes_module_callback,
+       .priority = 0
+};
+
 static int __init init_kprobes(void)
 {
        int i, err = 0;
@@ -1124,12 +1235,15 @@ static int __init init_kprobes(void)
                }
        }
 
-       /* By default, kprobes are enabled */
-       kprobe_enabled = true;
+       /* By default, kprobes are armed */
+       kprobes_all_disarmed = false;
 
        err = arch_init_kprobes();
        if (!err)
                err = register_die_notifier(&kprobe_exceptions_nb);
+       if (!err)
+               err = register_module_notifier(&kprobe_module_nb);
+
        kprobes_initialized = (err == 0);
 
        if (!err)
@@ -1150,10 +1264,18 @@ static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
        else
                kprobe_type = "k";
        if (sym)
-               seq_printf(pi, "%p  %s  %s+0x%x  %s\n", p->addr, kprobe_type,
-                       sym, offset, (modname ? modname : " "));
+               seq_printf(pi, "%p  %s  %s+0x%x  %s %s%s\n",
+                       p->addr, kprobe_type, sym, offset,
+                       (modname ? modname : " "),
+                       (kprobe_gone(p) ? "[GONE]" : ""),
+                       ((kprobe_disabled(p) && !kprobe_gone(p)) ?
+                        "[DISABLED]" : ""));
        else
-               seq_printf(pi, "%p  %s  %p\n", p->addr, kprobe_type, p->addr);
+               seq_printf(pi, "%p  %s  %p %s%s\n",
+                       p->addr, kprobe_type, p->addr,
+                       (kprobe_gone(p) ? "[GONE]" : ""),
+                       ((kprobe_disabled(p) && !kprobe_gone(p)) ?
+                        "[DISABLED]" : ""));
 }
 
 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
@@ -1199,7 +1321,7 @@ static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
        return 0;
 }
 
-static struct seq_operations kprobes_seq_ops = {
+static const struct seq_operations kprobes_seq_ops = {
        .start = kprobe_seq_start,
        .next  = kprobe_seq_next,
        .stop  = kprobe_seq_stop,
@@ -1211,14 +1333,79 @@ static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
        return seq_open(filp, &kprobes_seq_ops);
 }
 
-static struct file_operations debugfs_kprobes_operations = {
+static const struct file_operations debugfs_kprobes_operations = {
        .open           = kprobes_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
 };
 
-static void __kprobes enable_all_kprobes(void)
+/* Disable one kprobe */
+int __kprobes disable_kprobe(struct kprobe *kp)
+{
+       int ret = 0;
+       struct kprobe *p;
+
+       mutex_lock(&kprobe_mutex);
+
+       /* Check whether specified probe is valid. */
+       p = __get_valid_kprobe(kp);
+       if (unlikely(p == NULL)) {
+               ret = -EINVAL;
+               goto out;
+       }
+
+       /* If the probe is already disabled (or gone), just return */
+       if (kprobe_disabled(kp))
+               goto out;
+
+       kp->flags |= KPROBE_FLAG_DISABLED;
+       if (p != kp)
+               /* When kp != p, p is always enabled. */
+               try_to_disable_aggr_kprobe(p);
+
+       if (!kprobes_all_disarmed && kprobe_disabled(p))
+               disarm_kprobe(p);
+out:
+       mutex_unlock(&kprobe_mutex);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(disable_kprobe);
+
+/* Enable one kprobe */
+int __kprobes enable_kprobe(struct kprobe *kp)
+{
+       int ret = 0;
+       struct kprobe *p;
+
+       mutex_lock(&kprobe_mutex);
+
+       /* Check whether specified probe is valid. */
+       p = __get_valid_kprobe(kp);
+       if (unlikely(p == NULL)) {
+               ret = -EINVAL;
+               goto out;
+       }
+
+       if (kprobe_gone(kp)) {
+               /* This kprobe has gone, we couldn't enable it. */
+               ret = -EINVAL;
+               goto out;
+       }
+
+       if (!kprobes_all_disarmed && kprobe_disabled(p))
+               arm_kprobe(p);
+
+       p->flags &= ~KPROBE_FLAG_DISABLED;
+       if (p != kp)
+               kp->flags &= ~KPROBE_FLAG_DISABLED;
+out:
+       mutex_unlock(&kprobe_mutex);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(enable_kprobe);
+
+static void __kprobes arm_all_kprobes(void)
 {
        struct hlist_head *head;
        struct hlist_node *node;
@@ -1227,17 +1414,20 @@ static void __kprobes enable_all_kprobes(void)
 
        mutex_lock(&kprobe_mutex);
 
-       /* If kprobes are already enabled, just return */
-       if (kprobe_enabled)
+       /* If kprobes are armed, just return */
+       if (!kprobes_all_disarmed)
                goto already_enabled;
 
+       mutex_lock(&text_mutex);
        for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                head = &kprobe_table[i];
                hlist_for_each_entry_rcu(p, node, head, hlist)
-                       arch_arm_kprobe(p);
+                       if (!kprobe_disabled(p))
+                               arch_arm_kprobe(p);
        }
+       mutex_unlock(&text_mutex);
 
-       kprobe_enabled = true;
+       kprobes_all_disarmed = false;
        printk(KERN_INFO "Kprobes globally enabled\n");
 
 already_enabled:
@@ -1245,7 +1435,7 @@ already_enabled:
        return;
 }
 
-static void __kprobes disable_all_kprobes(void)
+static void __kprobes disarm_all_kprobes(void)
 {
        struct hlist_head *head;
        struct hlist_node *node;
@@ -1254,20 +1444,22 @@ static void __kprobes disable_all_kprobes(void)
 
        mutex_lock(&kprobe_mutex);
 
-       /* If kprobes are already disabled, just return */
-       if (!kprobe_enabled)
+       /* If kprobes are already disarmed, just return */
+       if (kprobes_all_disarmed)
                goto already_disabled;
 
-       kprobe_enabled = false;
+       kprobes_all_disarmed = true;
        printk(KERN_INFO "Kprobes globally disabled\n");
+       mutex_lock(&text_mutex);
        for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                head = &kprobe_table[i];
                hlist_for_each_entry_rcu(p, node, head, hlist) {
-                       if (!arch_trampoline_kprobe(p))
+                       if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
                                arch_disarm_kprobe(p);
                }
        }
 
+       mutex_unlock(&text_mutex);
        mutex_unlock(&kprobe_mutex);
        /* Allow all currently running kprobes to complete */
        synchronize_sched();
@@ -1288,7 +1480,7 @@ static ssize_t read_enabled_file_bool(struct file *file,
 {
        char buf[3];
 
-       if (kprobe_enabled)
+       if (!kprobes_all_disarmed)
                buf[0] = '1';
        else
                buf[0] = '0';
@@ -1311,19 +1503,19 @@ static ssize_t write_enabled_file_bool(struct file *file,
        case 'y':
        case 'Y':
        case '1':
-               enable_all_kprobes();
+               arm_all_kprobes();
                break;
        case 'n':
        case 'N':
        case '0':
-               disable_all_kprobes();
+               disarm_all_kprobes();
                break;
        }
 
        return count;
 }
 
-static struct file_operations fops_kp = {
+static const struct file_operations fops_kp = {
        .read =         read_enabled_file_bool,
        .write =        write_enabled_file_bool,
 };
@@ -1359,16 +1551,5 @@ late_initcall(debugfs_kprobe_init);
 
 module_init(init_kprobes);
 
-EXPORT_SYMBOL_GPL(register_kprobe);
-EXPORT_SYMBOL_GPL(unregister_kprobe);
-EXPORT_SYMBOL_GPL(register_kprobes);
-EXPORT_SYMBOL_GPL(unregister_kprobes);
-EXPORT_SYMBOL_GPL(register_jprobe);
-EXPORT_SYMBOL_GPL(unregister_jprobe);
-EXPORT_SYMBOL_GPL(register_jprobes);
-EXPORT_SYMBOL_GPL(unregister_jprobes);
+/* defined in arch/.../kernel/kprobes.c */
 EXPORT_SYMBOL_GPL(jprobe_return);
-EXPORT_SYMBOL_GPL(register_kretprobe);
-EXPORT_SYMBOL_GPL(unregister_kretprobe);
-EXPORT_SYMBOL_GPL(register_kretprobes);
-EXPORT_SYMBOL_GPL(unregister_kretprobes);