1 files changed, 51 insertions, 10 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 456ecedff2d4..334f37472c56 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -89,9 +89,10 @@ static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
         list_for_each_entry(kp, &p->list, list) {
                 if (kp->pre_handler) {
                         curr_kprobe = kp;
-                        kp->pre_handler(kp, regs);
-                        curr_kprobe = NULL;
+                        if (kp->pre_handler(kp, regs))
+                                return 1;
                 }
+                curr_kprobe = NULL;
         }
         return 0;
 }
@@ -125,6 +126,19 @@ static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
         return 0;
 }
 
+static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+        struct kprobe *kp = curr_kprobe;
+        if (curr_kprobe && kp->break_handler) {
+                if (kp->break_handler(kp, regs)) {
+                        curr_kprobe = NULL;
+                        return 1;
+                }
+        }
+        curr_kprobe = NULL;
+        return 0;
+}
+
 struct kprobe trampoline_p = {
                 .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
                 .pre_handler = trampoline_probe_handler,
@@ -258,18 +272,45 @@ static inline void free_rp_inst(struct kretprobe *rp)
 }
 
 /*
+ * Keep all fields in the kprobe consistent
+ */
+static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
+{
+        memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
+        memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
+}
+
+/*
+* Add the new probe to old_p->list. Fail if this is the
+* second jprobe at the address - two jprobes can't coexist
+*/
+static int add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
+{
+        struct kprobe *kp;
+
+        if (p->break_handler) {
+                list_for_each_entry(kp, &old_p->list, list) {
+                        if (kp->break_handler)
+                                return -EEXIST;
+                }
+                list_add_tail(&p->list, &old_p->list);
+        } else
+                list_add(&p->list, &old_p->list);
+        return 0;
+}
+
+/*
  * Fill in the required fields of the "manager kprobe". Replace the
  * earlier kprobe in the hlist with the manager kprobe
  */
 static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
 {
+        copy_kprobe(p, ap);
         ap->addr = p->addr;
-        memcpy(&ap->opcode, &p->opcode, sizeof(kprobe_opcode_t));
-        memcpy(&ap->ainsn, &p->ainsn, sizeof(struct arch_specific_insn));
-
         ap->pre_handler = aggr_pre_handler;
         ap->post_handler = aggr_post_handler;
         ap->fault_handler = aggr_fault_handler;
+        ap->break_handler = aggr_break_handler;
 
         INIT_LIST_HEAD(&ap->list);
         list_add(&p->list, &ap->list);
@@ -290,16 +331,16 @@ static int register_aggr_kprobe(struct kprobe *old_p, struct kprobe *p)
         int ret = 0;
         struct kprobe *ap;
 
-        if (old_p->break_handler || p->break_handler) {
-                ret = -EEXIST;  /* kprobe and jprobe can't (yet) coexist */
-        } else if (old_p->pre_handler == aggr_pre_handler) {
-                list_add(&p->list, &old_p->list);
+        if (old_p->pre_handler == aggr_pre_handler) {
+                copy_kprobe(old_p, p);
+                ret = add_new_kprobe(old_p, p);
         } else {
                 ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC);
                 if (!ap)
                         return -ENOMEM;
                 add_aggr_kprobe(ap, old_p);
-                list_add(&p->list, &ap->list);
+                copy_kprobe(ap, p);
+                ret = add_new_kprobe(ap, p);
         }
         return ret;
 }