diff --git a/configure.ac b/configure.ac
index f5cce81e..cc9b2431 100644
--- a/configure.ac
+++ b/configure.ac
@@ -202,6 +202,7 @@ AC_DEFUN([MCCTRL_FIND_KSYM],[
 
 MCCTRL_FIND_KSYM([sys_mount])
 MCCTRL_FIND_KSYM([sys_unshare])
+MCCTRL_FIND_KSYM([zap_page_range])
 
 AC_SUBST(CC)
 AC_SUBST(XCC)
diff --git a/executer/kernel/mcctrl/syscall.c b/executer/kernel/mcctrl/syscall.c
index 598840a3..631b635d 100644
--- a/executer/kernel/mcctrl/syscall.c
+++ b/executer/kernel/mcctrl/syscall.c
@@ -44,6 +44,7 @@
 #include <asm/uaccess.h>
 #include <asm/delay.h>
 #include <asm/io.h>
+#include "config.h"
 #include "mcctrl.h"
 #include <linux/version.h>
 
@@ -57,6 +58,17 @@
 #define	dprintk(...)
 #endif
 
+#ifdef MCCTRL_KSYM_zap_page_range
+static void
+(*mcctrl_zap_page_range)(struct vm_area_struct *vma, unsigned long start,
+		unsigned long size, struct zap_details *details)
+#if MCCTRL_KSYM_zap_page_range
+	= (void *)MCCTRL_KSYM_zap_page_range;
+#else
+	= &zap_page_range;
+#endif
+#endif
+
 static long pager_call(ihk_os_t os, struct syscall_request *req);
 
 #ifdef SC_DEBUG
@@ -1516,6 +1528,10 @@ static int clear_pte_range(uintptr_t start, uintptr_t len)
 		}
 		if (addr < end) {
 			error = zap_vma_ptes(vma, addr, end-addr);
+			if (error) {
+				mcctrl_zap_page_range(vma, addr, end-addr, NULL);
+				error = 0;
+			}
 			if (ret == 0) {
 				ret = error;
 			}
@@ -1663,12 +1679,7 @@ int __do_in_kernel_syscall(ihk_os_t os, struct mcctrl_channel *c, struct syscall
 				ppd->pid, ppd->rpgtable);
 		}
 
-		error = clear_pte_range(sc->args[0], sc->args[1]);
-		if (error) {
-			error = -ENOSYS;
-			goto out;
-		}
-		ret = 0;
+		ret = clear_pte_range(sc->args[0], sc->args[1]);
 		break;
 
 	case __NR_mprotect:
diff --git a/executer/user/mcexec.c b/executer/user/mcexec.c
index b2ce1e1e..fb8f0a2d 100644
--- a/executer/user/mcexec.c
+++ b/executer/user/mcexec.c
@@ -1842,17 +1842,12 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
 			return w.sr.args[0];
 
 		case __NR_mmap:
+		case __NR_munmap:
 		case __NR_mprotect:
 			/* reserved for internal use */
 			do_syscall_return(fd, cpu, -ENOSYS, 0, 0, 0, 0);
 			break;
 
-		case __NR_munmap:
-			ret = madvise((void *)w.sr.args[0], w.sr.args[1], MADV_DONTNEED);
-			SET_ERR(ret);
-			do_syscall_return(fd, cpu, ret, 0, 0, 0, 0);
-			break;
-
 #ifdef USE_SYSCALL_MOD_CALL
 		case 303:{
 			__dprintf("mcexec.c,mod_cal,mod=%ld,cmd=%ld\n", w.sr.args[0], w.sr.args[1]);