1 files changed, 388 insertions, 185 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 9737a76e106f..77981813a1e7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -317,12 +317,12 @@ void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
 /* We have preemption disabled.. so it is safe to use __ versions */
 static inline void set_kprobe_instance(struct kprobe *kp)
 {
-        __get_cpu_var(kprobe_instance) = kp;
+        __this_cpu_write(kprobe_instance, kp);
 }
 
 static inline void reset_kprobe_instance(void)
 {
-        __get_cpu_var(kprobe_instance) = NULL;
+        __this_cpu_write(kprobe_instance, NULL);
 }
 
 /*
@@ -354,13 +354,20 @@ static inline int kprobe_aggrprobe(struct kprobe *p)
         return p->pre_handler == aggr_pre_handler;
 }
 
+/* Return true(!0) if the kprobe is unused */
+static inline int kprobe_unused(struct kprobe *p)
+{
+        return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
+               list_empty(&p->list);
+}
+
 /*
  * Keep all fields in the kprobe consistent
  */
-static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
+static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
 {
-        memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
-        memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
+        memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
+        memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
 }
 
 #ifdef CONFIG_OPTPROBES
@@ -384,6 +391,17 @@ void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
         }
 }
 
+/* Free optimized instructions and optimized_kprobe */
+static __kprobes void free_aggr_kprobe(struct kprobe *p)
+{
+        struct optimized_kprobe *op;
+
+        op = container_of(p, struct optimized_kprobe, kp);
+        arch_remove_optimized_kprobe(op);
+        arch_remove_kprobe(p);
+        kfree(op);
+}
+
 /* Return true(!0) if the kprobe is ready for optimization. */
 static inline int kprobe_optready(struct kprobe *p)
 {
@@ -397,6 +415,33 @@ static inline int kprobe_optready(struct kprobe *p)
         return 0;
 }
 
+/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
+static inline int kprobe_disarmed(struct kprobe *p)
+{
+        struct optimized_kprobe *op;
+
+        /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
+        if (!kprobe_aggrprobe(p))
+                return kprobe_disabled(p);
+
+        op = container_of(p, struct optimized_kprobe, kp);
+
+        return kprobe_disabled(p) && list_empty(&op->list);
+}
+
+/* Return true(!0) if the probe is queued on (un)optimizing lists */
+static int __kprobes kprobe_queued(struct kprobe *p)
+{
+        struct optimized_kprobe *op;
+
+        if (kprobe_aggrprobe(p)) {
+                op = container_of(p, struct optimized_kprobe, kp);
+                if (!list_empty(&op->list))
+                        return 1;
+        }
+        return 0;
+}
+
 /*
  * Return an optimized kprobe whose optimizing code replaces
  * instructions including addr (exclude breakpoint).
@@ -422,30 +467,23 @@ static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
 
 /* Optimization staging list, protected by kprobe_mutex */
 static LIST_HEAD(optimizing_list);
+static LIST_HEAD(unoptimizing_list);
 
 static void kprobe_optimizer(struct work_struct *work);
 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
+static DECLARE_COMPLETION(optimizer_comp);
 #define OPTIMIZE_DELAY 5
 
-/* Kprobe jump optimizer */
-static __kprobes void kprobe_optimizer(struct work_struct *work)
+/*
+ * Optimize (replace a breakpoint with a jump) kprobes listed on
+ * optimizing_list.
+ */
+static __kprobes void do_optimize_kprobes(void)
 {
-        struct optimized_kprobe *op, *tmp;
-
-        /* Lock modules while optimizing kprobes */
-        mutex_lock(&module_mutex);
-        mutex_lock(&kprobe_mutex);
-        if (kprobes_all_disarmed || !kprobes_allow_optimization)
-                goto end;
-
-        /*
-         * Wait for quiesence period to ensure all running interrupts
-         * are done. Because optprobe may modify multiple instructions
-         * there is a chance that Nth instruction is interrupted. In that
-         * case, running interrupt can return to 2nd-Nth byte of jump
-         * instruction. This wait is for avoiding it.
-         */
-        synchronize_sched();
+        /* Optimization never be done when disarmed */
+        if (kprobes_all_disarmed || !kprobes_allow_optimization ||
+            list_empty(&optimizing_list))
+                return;
 
         /*
          * The optimization/unoptimization refers online_cpus via
@@ -459,17 +497,111 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
          */
         get_online_cpus();
         mutex_lock(&text_mutex);
-        list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
-                WARN_ON(kprobe_disabled(&op->kp));
-                if (arch_optimize_kprobe(op) < 0)
-                        op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
-                list_del_init(&op->list);
+        arch_optimize_kprobes(&optimizing_list);
+        mutex_unlock(&text_mutex);
+        put_online_cpus();
+}
+
+/*
+ * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
+ * if need) kprobes listed on unoptimizing_list.
+ */
+static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
+{
+        struct optimized_kprobe *op, *tmp;
+
+        /* Unoptimization must be done anytime */
+        if (list_empty(&unoptimizing_list))
+                return;
+
+        /* Ditto to do_optimize_kprobes */
+        get_online_cpus();
+        mutex_lock(&text_mutex);
+        arch_unoptimize_kprobes(&unoptimizing_list, free_list);
+        /* Loop free_list for disarming */
+        list_for_each_entry_safe(op, tmp, free_list, list) {
+                /* Disarm probes if marked disabled */
+                if (kprobe_disabled(&op->kp))
+                        arch_disarm_kprobe(&op->kp);
+                if (kprobe_unused(&op->kp)) {
+                        /*
+                         * Remove unused probes from hash list. After waiting
+                         * for synchronization, these probes are reclaimed.
+                         * (reclaiming is done by do_free_cleaned_kprobes.)
+                         */
+                        hlist_del_rcu(&op->kp.hlist);
+                } else
+                        list_del_init(&op->list);
         }
         mutex_unlock(&text_mutex);
         put_online_cpus();
-end:
+}
+
+/* Reclaim all kprobes on the free_list */
+static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
+{
+        struct optimized_kprobe *op, *tmp;
+
+        list_for_each_entry_safe(op, tmp, free_list, list) {
+                BUG_ON(!kprobe_unused(&op->kp));
+                list_del_init(&op->list);
+                free_aggr_kprobe(&op->kp);
+        }
+}
+
+/* Start optimizer after OPTIMIZE_DELAY passed */
+static __kprobes void kick_kprobe_optimizer(void)
+{
+        if (!delayed_work_pending(&optimizing_work))
+                schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
+}
+
+/* Kprobe jump optimizer */
+static __kprobes void kprobe_optimizer(struct work_struct *work)
+{
+        LIST_HEAD(free_list);
+
+        /* Lock modules while optimizing kprobes */
+        mutex_lock(&module_mutex);
+        mutex_lock(&kprobe_mutex);
+
+        /*
+         * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
+         * kprobes before waiting for quiesence period.
+         */
+        do_unoptimize_kprobes(&free_list);
+
+        /*
+         * Step 2: Wait for quiesence period to ensure all running interrupts
+         * are done. Because optprobe may modify multiple instructions
+         * there is a chance that Nth instruction is interrupted. In that
+         * case, running interrupt can return to 2nd-Nth byte of jump
+         * instruction. This wait is for avoiding it.
+         */
+        synchronize_sched();
+
+        /* Step 3: Optimize kprobes after quiesence period */
+        do_optimize_kprobes();
+
+        /* Step 4: Free cleaned kprobes after quiesence period */
+        do_free_cleaned_kprobes(&free_list);
+
         mutex_unlock(&kprobe_mutex);
         mutex_unlock(&module_mutex);
+
+        /* Step 5: Kick optimizer again if needed */
+        if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
+                kick_kprobe_optimizer();
+        else
+                /* Wake up all waiters */
+                complete_all(&optimizer_comp);
+}
+
+/* Wait for completing optimization and unoptimization */
+static __kprobes void wait_for_kprobe_optimizer(void)
+{
+        if (delayed_work_pending(&optimizing_work))
+                wait_for_completion(&optimizer_comp);
 }
 
 /* Optimize kprobe if p is ready to be optimized */
@@ -495,42 +627,99 @@ static __kprobes void optimize_kprobe(struct kprobe *p)
         /* Check if it is already optimized. */
         if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
                 return;
-
         op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
-        list_add(&op->list, &optimizing_list);
-        if (!delayed_work_pending(&optimizing_work))
-                schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
+
+        if (!list_empty(&op->list))
+                /* This is under unoptimizing. Just dequeue the probe */
+                list_del_init(&op->list);
+        else {
+                list_add(&op->list, &optimizing_list);
+                kick_kprobe_optimizer();
+        }
+}
+
+/* Short cut to direct unoptimizing */
+static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
+{
+        get_online_cpus();
+        arch_unoptimize_kprobe(op);
+        put_online_cpus();
+        if (kprobe_disabled(&op->kp))
+                arch_disarm_kprobe(&op->kp);
 }
 
 /* Unoptimize a kprobe if p is optimized */
-static __kprobes void unoptimize_kprobe(struct kprobe *p)
+static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
 {
         struct optimized_kprobe *op;
 
-        if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) {
-                op = container_of(p, struct optimized_kprobe, kp);
-                if (!list_empty(&op->list))
-                        /* Dequeue from the optimization queue */
+        if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
+                return; /* This is not an optprobe nor optimized */
+
+        op = container_of(p, struct optimized_kprobe, kp);
+        if (!kprobe_optimized(p)) {
+                /* Unoptimized or unoptimizing case */
+                if (force && !list_empty(&op->list)) {
+                        /*
+                         * Only if this is unoptimizing kprobe and forced,
+                         * forcibly unoptimize it. (No need to unoptimize
+                         * unoptimized kprobe again :)
+                         */
                         list_del_init(&op->list);
-                else
-                        /* Replace jump with break */
-                        arch_unoptimize_kprobe(op);
-                op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+                        force_unoptimize_kprobe(op);
+                }
+                return;
+        }
+
+        op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+        if (!list_empty(&op->list)) {
+                /* Dequeue from the optimization queue */
+                list_del_init(&op->list);
+                return;
+        }
+        /* Optimized kprobe case */
+        if (force)
+                /* Forcibly update the code: this is a special case */
+                force_unoptimize_kprobe(op);
+        else {
+                list_add(&op->list, &unoptimizing_list);
+                kick_kprobe_optimizer();
         }
 }
 
+/* Cancel unoptimizing for reusing */
+static void reuse_unused_kprobe(struct kprobe *ap)
+{
+        struct optimized_kprobe *op;
+
+        BUG_ON(!kprobe_unused(ap));
+        /*
+         * Unused kprobe MUST be on the way of delayed unoptimizing (means
+         * there is still a relative jump) and disabled.
+         */
+        op = container_of(ap, struct optimized_kprobe, kp);
+        if (unlikely(list_empty(&op->list)))
+                printk(KERN_WARNING "Warning: found a stray unused "
+                        "aggrprobe@%p\n", ap->addr);
+        /* Enable the probe again */
+        ap->flags &= ~KPROBE_FLAG_DISABLED;
+        /* Optimize it again (remove from op->list) */
+        BUG_ON(!kprobe_optready(ap));
+        optimize_kprobe(ap);
+}
+
 /* Remove optimized instructions */
 static void __kprobes kill_optimized_kprobe(struct kprobe *p)
 {
         struct optimized_kprobe *op;
 
         op = container_of(p, struct optimized_kprobe, kp);
-        if (!list_empty(&op->list)) {
-                /* Dequeue from the optimization queue */
+        if (!list_empty(&op->list))
+                /* Dequeue from the (un)optimization queue */
                 list_del_init(&op->list);
-                op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
-        }
-        /* Don't unoptimize, because the target code will be freed. */
+
+        op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+        /* Don't touch the code, because it is already freed. */
         arch_remove_optimized_kprobe(op);
 }
 
@@ -543,16 +732,6 @@ static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
         arch_prepare_optimized_kprobe(op);
 }
 
-/* Free optimized instructions and optimized_kprobe */
-static __kprobes void free_aggr_kprobe(struct kprobe *p)
-{
-        struct optimized_kprobe *op;
-
-        op = container_of(p, struct optimized_kprobe, kp);
-        arch_remove_optimized_kprobe(op);
-        kfree(op);
-}
-
 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
 {
@@ -587,7 +766,8 @@ static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
         op = container_of(ap, struct optimized_kprobe, kp);
         if (!arch_prepared_optinsn(&op->optinsn)) {
                 /* If failed to setup optimizing, fallback to kprobe */
-                free_aggr_kprobe(ap);
+                arch_remove_optimized_kprobe(op);
+                kfree(op);
                 return;
         }
 
@@ -631,21 +811,16 @@ static void __kprobes unoptimize_all_kprobes(void)
                 return;
 
         kprobes_allow_optimization = false;
-        printk(KERN_INFO "Kprobes globally unoptimized\n");
-        get_online_cpus();      /* For avoiding text_mutex deadlock */
-        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 (!kprobe_disabled(p))
-                                unoptimize_kprobe(p);
+                                unoptimize_kprobe(p, false);
                 }
         }
-
-        mutex_unlock(&text_mutex);
-        put_online_cpus();
-        /* Allow all currently running kprobes to complete */
-        synchronize_sched();
+        /* Wait for unoptimizing completion */
+        wait_for_kprobe_optimizer();
+        printk(KERN_INFO "Kprobes globally unoptimized\n");
 }
 
 int sysctl_kprobes_optimization;
@@ -669,44 +844,60 @@ int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
 }
 #endif /* CONFIG_SYSCTL */
 
+/* Put a breakpoint for a probe. Must be called with text_mutex locked */
 static void __kprobes __arm_kprobe(struct kprobe *p)
 {
-        struct kprobe *old_p;
+        struct kprobe *_p;
 
         /* Check collision with other optimized kprobes */
-        old_p = get_optimized_kprobe((unsigned long)p->addr);
-        if (unlikely(old_p))
-                unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */
+        _p = get_optimized_kprobe((unsigned long)p->addr);
+        if (unlikely(_p))
+                /* Fallback to unoptimized kprobe */
+                unoptimize_kprobe(_p, true);
 
         arch_arm_kprobe(p);
         optimize_kprobe(p);     /* Try to optimize (add kprobe to a list) */
 }
 
-static void __kprobes __disarm_kprobe(struct kprobe *p)
+/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
+static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
 {
-        struct kprobe *old_p;
+        struct kprobe *_p;
 
-        unoptimize_kprobe(p);   /* Try to unoptimize */
-        arch_disarm_kprobe(p);
+        unoptimize_kprobe(p, false);    /* Try to unoptimize */
 
-        /* If another kprobe was blocked, optimize it. */
-        old_p = get_optimized_kprobe((unsigned long)p->addr);
-        if (unlikely(old_p))
-                optimize_kprobe(old_p);
+        if (!kprobe_queued(p)) {
+                arch_disarm_kprobe(p);
+                /* If another kprobe was blocked, optimize it. */
+                _p = get_optimized_kprobe((unsigned long)p->addr);
+                if (unlikely(_p) && reopt)
+                        optimize_kprobe(_p);
+        }
+        /* TODO: reoptimize others after unoptimized this probe */
 }
 
 #else /* !CONFIG_OPTPROBES */
 
 #define optimize_kprobe(p)                      do {} while (0)
-#define unoptimize_kprobe(p)                    do {} while (0)
+#define unoptimize_kprobe(p, f)                 do {} while (0)
 #define kill_optimized_kprobe(p)                do {} while (0)
 #define prepare_optimized_kprobe(p)             do {} while (0)
 #define try_to_optimize_kprobe(p)               do {} while (0)
 #define __arm_kprobe(p)                         arch_arm_kprobe(p)
-#define __disarm_kprobe(p)                      arch_disarm_kprobe(p)
+#define __disarm_kprobe(p, o)                   arch_disarm_kprobe(p)
+#define kprobe_disarmed(p)                      kprobe_disabled(p)
+#define wait_for_kprobe_optimizer()             do {} while (0)
+
+/* There should be no unused kprobes can be reused without optimization */
+static void reuse_unused_kprobe(struct kprobe *ap)
+{
+        printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
+        BUG_ON(kprobe_unused(ap));
+}
 
 static __kprobes void free_aggr_kprobe(struct kprobe *p)
 {
+        arch_remove_kprobe(p);
         kfree(p);
 }
 
@@ -732,11 +923,10 @@ static void __kprobes arm_kprobe(struct kprobe *kp)
 /* Disarm a kprobe with text_mutex */
 static void __kprobes disarm_kprobe(struct kprobe *kp)
 {
-        get_online_cpus();      /* For avoiding text_mutex deadlock */
+        /* Ditto */
         mutex_lock(&text_mutex);
-        __disarm_kprobe(kp);
+        __disarm_kprobe(kp, true);
         mutex_unlock(&text_mutex);
-        put_online_cpus();
 }
 
 /*
@@ -775,7 +965,7 @@ static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
 static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
                                         int trapnr)
 {
-        struct kprobe *cur = __get_cpu_var(kprobe_instance);
+        struct kprobe *cur = __this_cpu_read(kprobe_instance);
 
         /*
          * if we faulted "during" the execution of a user specified
@@ -790,7 +980,7 @@ static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
 
 static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
 {
-        struct kprobe *cur = __get_cpu_var(kprobe_instance);
+        struct kprobe *cur = __this_cpu_read(kprobe_instance);
         int ret = 0;
 
         if (cur && cur->break_handler) {
@@ -942,7 +1132,7 @@ static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
         BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
 
         if (p->break_handler || p->post_handler)
-                unoptimize_kprobe(ap);  /* Fall back to normal kprobe */
+                unoptimize_kprobe(ap, true);    /* Fall back to normal kprobe */
 
         if (p->break_handler) {
                 if (ap->break_handler)
@@ -993,19 +1183,21 @@ static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
  * This is the second or subsequent kprobe at the address - handle
  * the intricacies
  */
-static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
+static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
                                           struct kprobe *p)
 {
         int ret = 0;
-        struct kprobe *ap = old_p;
+        struct kprobe *ap = orig_p;
 
-        if (!kprobe_aggrprobe(old_p)) {
-                /* If old_p is not an aggr_kprobe, create new aggr_kprobe. */
-                ap = alloc_aggr_kprobe(old_p);
+        if (!kprobe_aggrprobe(orig_p)) {
+                /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
+                ap = alloc_aggr_kprobe(orig_p);
                 if (!ap)
                         return -ENOMEM;
-                init_aggr_kprobe(ap, old_p);
-        }
+                init_aggr_kprobe(ap, orig_p);
+        } else if (kprobe_unused(ap))
+                /* This probe is going to die. Rescue it */
+                reuse_unused_kprobe(ap);
 
         if (kprobe_gone(ap)) {
                 /*
@@ -1039,23 +1231,6 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_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)
 {
         struct kprobe_blackpoint *kb;
@@ -1098,34 +1273,33 @@ static kprobe_opcode_t __kprobes *kprobe_addr(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;
+        struct kprobe *ap, *list_p;
 
-        old_p = get_kprobe(p->addr);
-        if (unlikely(!old_p))
+        ap = get_kprobe(p->addr);
+        if (unlikely(!ap))
                 return NULL;
 
-        if (p != old_p) {
-                list_for_each_entry_rcu(list_p, &old_p->list, list)
+        if (p != ap) {
+                list_for_each_entry_rcu(list_p, &ap->list, list)
                         if (list_p == p)
                         /* kprobe p is a valid probe */
                                 goto valid;
                 return NULL;
         }
 valid:
-        return old_p;
+        return ap;
 }
 
 /* Return error if the kprobe is being re-registered */
 static inline int check_kprobe_rereg(struct kprobe *p)
 {
         int ret = 0;
-        struct kprobe *old_p;
 
         mutex_lock(&kprobe_mutex);
-        old_p = __get_valid_kprobe(p);
-        if (old_p)
+        if (__get_valid_kprobe(p))
                 ret = -EINVAL;
         mutex_unlock(&kprobe_mutex);
+
         return ret;
 }
 
@@ -1229,67 +1403,121 @@ fail_with_jump_label:
 }
 EXPORT_SYMBOL_GPL(register_kprobe);
 
+/* Check if all probes on the aggrprobe are disabled */
+static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
+{
+        struct kprobe *kp;
+
+        list_for_each_entry_rcu(kp, &ap->list, list)
+                if (!kprobe_disabled(kp))
+                        /*
+                         * There is an active probe on the list.
+                         * We can't disable this ap.
+                         */
+                        return 0;
+
+        return 1;
+}
+
+/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
+static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
+{
+        struct kprobe *orig_p;
+
+        /* Get an original kprobe for return */
+        orig_p = __get_valid_kprobe(p);
+        if (unlikely(orig_p == NULL))
+                return NULL;
+
+        if (!kprobe_disabled(p)) {
+                /* Disable probe if it is a child probe */
+                if (p != orig_p)
+                        p->flags |= KPROBE_FLAG_DISABLED;
+
+                /* Try to disarm and disable this/parent probe */
+                if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
+                        disarm_kprobe(orig_p);
+                        orig_p->flags |= KPROBE_FLAG_DISABLED;
+                }
+        }
+
+        return orig_p;
+}
+
 /*
  * Unregister a kprobe without a scheduler synchronization.
  */
 static int __kprobes __unregister_kprobe_top(struct kprobe *p)
 {
-        struct kprobe *old_p, *list_p;
+        struct kprobe *ap, *list_p;
 
-        old_p = __get_valid_kprobe(p);
-        if (old_p == NULL)
+        /* Disable kprobe. This will disarm it if needed. */
+        ap = __disable_kprobe(p);
+        if (ap == NULL)
                 return -EINVAL;
 
-        if (old_p == p ||
-            (kprobe_aggrprobe(old_p) &&
-             list_is_singular(&old_p->list))) {
+        if (ap == p)
                 /*
-                 * Only probe on the hash list. Disarm only if kprobes are
-                 * enabled and not gone - otherwise, the breakpoint would
-                 * already have been removed. We save on flushing icache.
+                 * This probe is an independent(and non-optimized) kprobe
+                 * (not an aggrprobe). Remove from the hash list.
                  */
-                if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
-                        disarm_kprobe(old_p);
-                hlist_del_rcu(&old_p->hlist);
-        } else {
+                goto disarmed;
+
+        /* Following process expects this probe is an aggrprobe */
+        WARN_ON(!kprobe_aggrprobe(ap));
+
+        if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
+                /*
+                 * !disarmed could be happen if the probe is under delayed
+                 * unoptimizing.
+                 */
+                goto disarmed;
+        else {
+                /* If disabling probe has special handlers, update aggrprobe */
                 if (p->break_handler && !kprobe_gone(p))
-                        old_p->break_handler = NULL;
+                        ap->break_handler = NULL;
                 if (p->post_handler && !kprobe_gone(p)) {
-                        list_for_each_entry_rcu(list_p, &old_p->list, list) {
+                        list_for_each_entry_rcu(list_p, &ap->list, list) {
                                 if ((list_p != p) && (list_p->post_handler))
                                         goto noclean;
                         }
-                        old_p->post_handler = NULL;
+                        ap->post_handler = NULL;
                 }
 noclean:
+                /*
+                 * Remove from the aggrprobe: this path will do nothing in
+                 * __unregister_kprobe_bottom().
+                 */
                 list_del_rcu(&p->list);
-                if (!kprobe_disabled(old_p)) {
-                        try_to_disable_aggr_kprobe(old_p);
-                        if (!kprobes_all_disarmed) {
-                                if (kprobe_disabled(old_p))
-                                        disarm_kprobe(old_p);
-                                else
-                                        /* Try to optimize this probe again */
-                                        optimize_kprobe(old_p);
-                        }
-                }
+                if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
+                        /*
+                         * Try to optimize this probe again, because post
+                         * handler may have been changed.
+                         */
+                        optimize_kprobe(ap);
         }
         return 0;
+
+disarmed:
+        BUG_ON(!kprobe_disarmed(ap));
+        hlist_del_rcu(&ap->hlist);
+        return 0;
 }
 
 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
 {
-        struct kprobe *old_p;
+        struct kprobe *ap;
 
         if (list_empty(&p->list))
+                /* This is an independent kprobe */
                 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);
+                /* This is the last child of an aggrprobe */
+                ap = list_entry(p->list.next, struct kprobe, list);
                 list_del(&p->list);
-                arch_remove_kprobe(old_p);
-                free_aggr_kprobe(old_p);
+                free_aggr_kprobe(ap);
         }
+        /* Otherwise, do nothing. */
 }
 
 int __kprobes register_kprobes(struct kprobe **kps, int num)
@@ -1607,29 +1835,13 @@ static void __kprobes kill_kprobe(struct kprobe *p)
 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)) {
+        /* Disable this kprobe */
+        if (__disable_kprobe(kp) == 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;
 }
@@ -1927,36 +2139,27 @@ static void __kprobes disarm_all_kprobes(void)
         mutex_lock(&kprobe_mutex);
 
         /* If kprobes are already disarmed, just return */
-        if (kprobes_all_disarmed)
-                goto already_disabled;
+        if (kprobes_all_disarmed) {
+                mutex_unlock(&kprobe_mutex);
+                return;
+        }
 
         kprobes_all_disarmed = true;
         printk(KERN_INFO "Kprobes globally disabled\n");
 
-        /*
-         * Here we call get_online_cpus() for avoiding text_mutex deadlock,
-         * because disarming may also unoptimize kprobes.
-         */
-        get_online_cpus();
         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) && !kprobe_disabled(p))
-                                __disarm_kprobe(p);
+                                __disarm_kprobe(p, false);
                 }
         }
-
         mutex_unlock(&text_mutex);
-        put_online_cpus();
         mutex_unlock(&kprobe_mutex);
-        /* Allow all currently running kprobes to complete */
-        synchronize_sched();
-        return;
 
-already_disabled:
-        mutex_unlock(&kprobe_mutex);
-        return;
+        /* Wait for disarming all kprobes by optimizer */
+        wait_for_kprobe_optimizer();
 }
 
 /*