diff --git a/arch/x86/kernel/syscall.c b/arch/x86/kernel/syscall.c
index e3e3ce78..d194533f 100644
--- a/arch/x86/kernel/syscall.c
+++ b/arch/x86/kernel/syscall.c
@@ -295,6 +295,15 @@ do_kill(int pid, int tid, int sig)
 		if(pid == proc->pid || pid == 0){
 			tproc = proc;
 		}
+		else{
+			for(i = 0; i < num_processors; i++){
+				if(get_cpu_local_var(i)->current &&
+				   get_cpu_local_var(i)->current->pid == pid){
+					tproc = get_cpu_local_var(i)->current;
+					break;
+				}
+			}
+		}
 	}
 	else if(pid == -1){
 		for(i = 0; i < num_processors; i++)
@@ -358,6 +367,9 @@ do_kill(int pid, int tid, int sig)
 	else{
 		ihk_mc_spinlock_unlock(&tproc->sigpendinglock, irqstate);
 	}
+	if(proc != tproc){
+		ihk_mc_interrupt_cpu(get_x86_cpu_local_variable(tproc->cpu_id)->apic_id, 0xd0);
+	}
 	interrupt_syscall(1);
 	return rc;
 }
diff --git a/executer/include/uprotocol.h b/executer/include/uprotocol.h
index b0d7500c..47540578 100644
--- a/executer/include/uprotocol.h
+++ b/executer/include/uprotocol.h
@@ -134,9 +134,17 @@ struct prepare_dma_desc {
 	unsigned long size;
 	unsigned long pa;
 };
+
 struct free_dma_desc {
 	unsigned long pa;
 	unsigned long size;
 };
 
+struct signal_desc {
+	int cpu;
+	int pid;
+	int tid;
+	int sig;
+};
+
 #endif
diff --git a/executer/kernel/control.c b/executer/kernel/control.c
index ff632bc7..4b0c837d 100644
--- a/executer/kernel/control.c
+++ b/executer/kernel/control.c
@@ -268,16 +268,21 @@ static long mcexec_start_image(ihk_os_t os,
 	return 0;
 }
 
-static long mcexec_send_signal(ihk_os_t os, unsigned long sigparam)
+static long mcexec_send_signal(ihk_os_t os, struct signal_desc *sigparam)
 {
 	struct ikc_scd_packet isp;
 	struct mcctrl_channel *c;
 	struct mcctrl_usrdata *usrdata = ihk_host_os_get_usrdata(os);
+	struct signal_desc sig;
 
+	if (copy_from_user(&sig, sigparam, sizeof(struct signal_desc))) {
+		return -EFAULT;
+	}
 	c = usrdata->channels;
 	isp.msg = SCD_MSG_SEND_SIGNAL;
-	isp.ref = 0;
-	isp.arg = sigparam;
+	isp.ref = sig.cpu;
+	isp.pid = sig.pid;
+	isp.arg = (long)sig.tid << 32 | (sig.sig & 0x00000000ffffffffL);
 
 	mcctrl_ikc_send(os, 0, &isp);
 
@@ -758,7 +763,7 @@ long __mcctrl_control(ihk_os_t os, unsigned int req, unsigned long arg)
 		return mcexec_load_syscall(os, (struct syscall_load_desc *)arg);
 
 	case MCEXEC_UP_SEND_SIGNAL:
-		return mcexec_send_signal(os, arg);
+		return mcexec_send_signal(os, (struct signal_desc *)arg);
 
 	case MCEXEC_UP_GET_CPU:
 		return mcexec_get_cpu(os);
diff --git a/executer/user/mcexec.c b/executer/user/mcexec.c
index 3e1a05d8..04d57a34 100644
--- a/executer/user/mcexec.c
+++ b/executer/user/mcexec.c
@@ -574,23 +574,44 @@ static void *main_loop_thread_func(void *arg)
 void
 sendsig(int sig, siginfo_t *siginfo, void *context)
 {
-	unsigned long	param;
+	pid_t	pid = getpid();
 	pid_t	tid = gettid();
 	int	i;
+	int	cpu;
+	struct signal_desc sigdesc;
 
-	if(tid != master_tid){
-		for(i = 0; i < ncpu; i++)
+
+	if(siginfo->si_pid == pid &&
+	   siginfo->si_signo == SIGINT)
+		return;
+	if(tid == thread_data[0].tid){
+		cpu = thread_data[0].cpu;
+		tid = master_tid;
+	}
+	else if(tid != master_tid){
+		for(i = 1; i < ncpu; i++)
 			if(thread_data[i].tid == tid){
 				if(thread_data[i].terminate)
 					return;
 				break;
 			}
-		if(i == ncpu)
-			return;
+		if(i != ncpu)
+			cpu = thread_data[i].cpu;
+		else{
+			cpu = 0;
+			tid = -1;
+		}
+	}
+	else{
+		cpu = 0;
+		tid = -1;
 	}
 
-	param = ((unsigned long)sig) << 32 | ((unsigned long)getpid());
-	if (ioctl(fd, MCEXEC_UP_SEND_SIGNAL, param) != 0) {
+	sigdesc.cpu = cpu;
+	sigdesc.pid = (int)pid;
+	sigdesc.tid = (int)tid;
+	sigdesc.sig = sig;
+	if (ioctl(fd, MCEXEC_UP_SEND_SIGNAL, &sigdesc) != 0) {
 		perror("send_signal");
 		close(fd);
 		exit(1);
@@ -702,7 +723,6 @@ int main(int argc, char **argv)
 	int envs_len;
 	char *envs;
 	char *args;
-	char **a;
 	char *p;
 	int i;
 	int error;
@@ -976,14 +996,12 @@ static void
 kill_thread(unsigned long cpu)
 {
 	if(cpu >= 0 && cpu < ncpu){
-		thread_data[cpu].terminate = 1;
 		pthread_kill(thread_data[cpu].thread_id, SIGINT);
 	}
 	else{
 		int	i;
 
 		for (i = 0; i < ncpu; ++i) {
-			thread_data[i].terminate = 1;
 			pthread_kill(thread_data[i].thread_id, SIGINT);
 		}
 	}
diff --git a/kernel/host.c b/kernel/host.c
index 1a14e194..7f469fa1 100644
--- a/kernel/host.c
+++ b/kernel/host.c
@@ -535,7 +535,7 @@ static int syscall_packet_handler(struct ihk_ikc_channel_desc *c,
 		//cpu_local_var(next) = (struct process *)packet->arg;
 		return 0;
 	case SCD_MSG_SEND_SIGNAL:
-		rc = do_kill((int)packet->arg, -1, (int)(packet->arg >> 32));
+		rc = do_kill((int)packet->pid, (int)(packet->arg >> 32), packet->arg & 0x00000000ffffffffL);
 		kprintf("SCD_MSG_SEND_SIGNAL: %lx, rc=%d\n", packet->arg, rc);
 		return 0;
 	}
diff --git a/kernel/syscall.c b/kernel/syscall.c
index 8535a222..94924394 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -94,6 +94,7 @@ static char *syscall_name[] MCKERNEL_UNUSED = {
 
 void check_signal(unsigned long rc, void *regs);
 void do_signal(long rc, void *regs, struct process *proc, struct sig_pending *pending);
+extern unsigned long do_kill(int pid, int tid, int sig);
 int copy_from_user(struct process *, void *, const void *, size_t);
 int copy_to_user(struct process *, void *, const void *, size_t);
 
@@ -415,7 +416,10 @@ terminate(int rc, int sig, ihk_mc_user_context_t *ctx)
 		/* Signal parent if still attached */
 		ihk_mc_spinlock_lock_noirq(&ftn->parent->lock);
 		if (ftn->parent->owner) {
+			do_kill(ftn->parent->owner->pid, -1, SIGCHLD);
+/*
 			sigchld_parent(ftn->parent->owner, 0);
+*/
 		}
 		ihk_mc_spinlock_unlock_noirq(&ftn->parent->lock);	
 		
@@ -1335,8 +1339,6 @@ SYSCALL_DECLARE(set_tid_address)
 	return cpu_local_var(current)->pid;
 }
 
-extern unsigned long do_kill(int pid, int tid, int sig);
-
 SYSCALL_DECLARE(kill)
 {
 	int pid = ihk_mc_syscall_arg0(ctx);