1 files changed, 3 insertions, 36 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 4b8a4493c541..f9798ff7899f 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -64,7 +64,6 @@
 
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
-static atomic_t kprobe_count;
 
 /* NOTE: change this value only with kprobe_mutex held */
 static bool kprobe_enabled;
@@ -73,11 +72,6 @@ DEFINE_MUTEX(kprobe_mutex);		/* Protects kprobe_table */
 DEFINE_SPINLOCK(kretprobe_lock);        /* Protects kretprobe_inst_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
 
-static struct notifier_block kprobe_page_fault_nb = {
-        .notifier_call = kprobe_exceptions_notify,
-        .priority = 0x7fffffff /* we need to notified first */
-};
-
 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 /*
  * kprobe->ainsn.insn points to the copy of the instruction to be
@@ -556,8 +550,6 @@ static int __kprobes __register_kprobe(struct kprobe *p,
         old_p = get_kprobe(p->addr);
         if (old_p) {
                 ret = register_aggr_kprobe(old_p, p);
-                if (!ret)
-                        atomic_inc(&kprobe_count);
                 goto out;
         }
 
@@ -569,13 +561,9 @@ static int __kprobes __register_kprobe(struct kprobe *p,
         hlist_add_head_rcu(&p->hlist,
                        &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
 
-        if (kprobe_enabled) {
-                if (atomic_add_return(1, &kprobe_count) == \
-                                (ARCH_INACTIVE_KPROBE_COUNT + 1))
-                        register_page_fault_notifier(&kprobe_page_fault_nb);
-
+        if (kprobe_enabled)
                 arch_arm_kprobe(p);
-        }
+
 out:
         mutex_unlock(&kprobe_mutex);
 
@@ -658,16 +646,6 @@ valid_p:
                 }
                 mutex_unlock(&kprobe_mutex);
         }
-
-        /* Call unregister_page_fault_notifier()
-         * if no probes are active
-         */
-        mutex_lock(&kprobe_mutex);
-        if (atomic_add_return(-1, &kprobe_count) == \
-                                ARCH_INACTIVE_KPROBE_COUNT)
-                unregister_page_fault_notifier(&kprobe_page_fault_nb);
-        mutex_unlock(&kprobe_mutex);
-        return;
 }
 
 static struct notifier_block kprobe_exceptions_nb = {
@@ -815,7 +793,6 @@ static int __init init_kprobes(void)
                 INIT_HLIST_HEAD(&kprobe_table[i]);
                 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
         }
-        atomic_set(&kprobe_count, 0);
 
         /* By default, kprobes are enabled */
         kprobe_enabled = true;
@@ -921,13 +898,6 @@ static void __kprobes enable_all_kprobes(void)
         if (kprobe_enabled)
                 goto already_enabled;
 
-        /*
-         * Re-register the page fault notifier only if there are any
-         * active probes at the time of enabling kprobes globally
-         */
-        if (atomic_read(&kprobe_count) > ARCH_INACTIVE_KPROBE_COUNT)
-                register_page_fault_notifier(&kprobe_page_fault_nb);
-
         for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                 head = &kprobe_table[i];
                 hlist_for_each_entry_rcu(p, node, head, hlist)
@@ -968,10 +938,7 @@ static void __kprobes disable_all_kprobes(void)
         mutex_unlock(&kprobe_mutex);
         /* Allow all currently running kprobes to complete */
         synchronize_sched();
-
-        mutex_lock(&kprobe_mutex);
-        /* Unconditionally unregister the page_fault notifier */
-        unregister_page_fault_notifier(&kprobe_page_fault_nb);
+        return;
 
 already_disabled:
         mutex_unlock(&kprobe_mutex);