3 files changed, 46 insertions, 6 deletions

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 25a8af76feb5..5940282bd2f9 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -1457,6 +1457,46 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist)
         text_poke_smp_batch(jump_poke_params, c);
 }
 
+static void __kprobes setup_unoptimize_kprobe(struct text_poke_param *tprm,
+                                              u8 *insn_buf,
+                                              struct optimized_kprobe *op)
+{
+        /* Set int3 to first byte for kprobes */
+        insn_buf[0] = BREAKPOINT_INSTRUCTION;
+        memcpy(insn_buf + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE);
+
+        tprm->addr = op->kp.addr;
+        tprm->opcode = insn_buf;
+        tprm->len = RELATIVEJUMP_SIZE;
+}
+
+/*
+ * Recover original instructions and breakpoints from relative jumps.
+ * Caller must call with locking kprobe_mutex.
+ */
+extern void arch_unoptimize_kprobes(struct list_head *oplist,
+                                    struct list_head *done_list)
+{
+        struct optimized_kprobe *op, *tmp;
+        int c = 0;
+
+        list_for_each_entry_safe(op, tmp, oplist, list) {
+                /* Setup param */
+                setup_unoptimize_kprobe(&jump_poke_params[c],
+                                        jump_poke_bufs[c].buf, op);
+                list_move(&op->list, done_list);
+                if (++c >= MAX_OPTIMIZE_PROBES)
+                        break;
+        }
+
+        /*
+         * text_poke_smp doesn't support NMI/MCE code modifying.
+         * However, since kprobes itself also doesn't support NMI/MCE
+         * code probing, it's not a problem.
+         */
+        text_poke_smp_batch(jump_poke_params, c);
+}
+
 /* Replace a relative jump with a breakpoint (int3).  */
 void __kprobes arch_unoptimize_kprobe(struct optimized_kprobe *op)
 {
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index fe157ba6aa0e..b78edb58ee66 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -276,6 +276,8 @@ extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 extern void arch_optimize_kprobes(struct list_head *oplist);
+extern void arch_unoptimize_kprobes(struct list_head *oplist,
+                                    struct list_head *done_list);
 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 extern kprobe_opcode_t *get_optinsn_slot(void);
 extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 531e10164836..7663e5df0e6f 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -517,9 +517,9 @@ static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
         /* Ditto to do_optimize_kprobes */
         get_online_cpus();
         mutex_lock(&text_mutex);
-        list_for_each_entry_safe(op, tmp, &unoptimizing_list, list) {
-                /* Unoptimize kprobes */
-                arch_unoptimize_kprobe(op);
+        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);
@@ -530,8 +530,6 @@ static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
                          * (reclaiming is done by do_free_cleaned_kprobes.)
                          */
                         hlist_del_rcu(&op->kp.hlist);
-                        /* Move only unused probes on free_list */
-                        list_move(&op->list, free_list);
                 } else
                         list_del_init(&op->list);
         }
@@ -592,7 +590,7 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
         mutex_unlock(&module_mutex);
 
         /* Step 5: Kick optimizer again if needed */
-        if (!list_empty(&optimizing_list))
+        if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
                 kick_kprobe_optimizer();
         else
                 /* Wake up all waiters */