1 files changed, 72 insertions, 56 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8c3aa1452201..ab99caf2b167 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1039,23 +1039,6 @@ static int __kprobes register_aggr_kprobe(struct kprobe *orig_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;
@@ -1228,6 +1211,47 @@ 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.
  */
@@ -1235,22 +1259,26 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
 {
         struct kprobe *ap, *list_p;
 
-        ap = __get_valid_kprobe(p);
+        /* Disable kprobe. This will disarm it if needed. */
+        ap = __disable_kprobe(p);
         if (ap == NULL)
                 return -EINVAL;
 
-        if (ap == p ||
-            (kprobe_aggrprobe(ap) &&
-             list_is_singular(&ap->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(ap))
-                        disarm_kprobe(ap);
-                hlist_del_rcu(&ap->hlist);
-        } else {
+                goto disarmed;
+
+        /* Following process expects this probe is an aggrprobe */
+        WARN_ON(!kprobe_aggrprobe(ap));
+
+        if (list_is_singular(&ap->list))
+                /* This probe is the last child of aggrprobe */
+                goto disarmed;
+        else {
+                /* If disabling probe has special handlers, update aggrprobe */
                 if (p->break_handler && !kprobe_gone(p))
                         ap->break_handler = NULL;
                 if (p->post_handler && !kprobe_gone(p)) {
@@ -1261,19 +1289,23 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
                         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(ap)) {
-                        try_to_disable_aggr_kprobe(ap);
-                        if (!kprobes_all_disarmed) {
-                                if (kprobe_disabled(ap))
-                                        disarm_kprobe(ap);
-                                else
-                                        /* Try to optimize this probe again */
-                                        optimize_kprobe(ap);
-                        }
-                }
+                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:
+        hlist_del_rcu(&ap->hlist);
+        return 0;
 }
 
 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
@@ -1606,29 +1638,13 @@ 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;
 }