diff --git a/kernel/channel.c b/kernel/channel.c
index 27ad372..ce342d2 100644
--- a/kernel/channel.c
+++ b/kernel/channel.c
@@ -1,5 +1,6 @@
 #include <kernel/channel.h>
 #include <kernel/msg.h>
+#include <kernel/port.h>
 #include <kernel/util.h>
 #include <kernel/vm-region.h>
 
@@ -80,6 +81,7 @@ static void kmsg_reply_error(
 	unsigned long *lock_flags)
 {
 	msg->msg_status = KMSG_REPLY_SENT;
+	msg->msg_sender_port->p_status = PORT_READY;
 	msg->msg_result = status;
 	thread_awaken(msg->msg_sender_thread);
 	spin_unlock_irqrestore(&msg->msg_lock, *lock_flags);
@@ -95,6 +97,7 @@ static struct kmsg *get_next_msg(
 		spin_lock_irqsave(&msg->msg_lock, lock_flags);
 		if (msg->msg_status == KMSG_WAIT_RECEIVE) {
 			msg->msg_status = KMSG_WAIT_REPLY;
+			msg->msg_sender_port->p_status = PORT_REPLY_BLOCKED;
 			return msg;
 		}
 
@@ -149,17 +152,24 @@ extern kern_status_t channel_recv_msg(
 	struct task *sender = msg->msg_sender_thread->tr_parent;
 	struct task *receiver = self->tr_parent;
 
+	struct vm_region *src = sender->t_address_space,
+			 *dst = receiver->t_address_space;
+	unsigned long f;
+	vm_region_lock_pair_irqsave(src, dst, &f);
+
 	kern_status_t status = vm_region_memmove_v(
-		receiver->t_address_space,
+		dst,
 		0,
 		out_msg->msg_data,
 		out_msg->msg_data_count,
-		sender->t_address_space,
+		src,
 		0,
 		msg->msg_req.msg_data,
 		msg->msg_req.msg_data_count,
 		VM_REGION_COPY_ALL,
 		NULL);
+	vm_region_unlock_pair_irqrestore(src, dst, f);
+
 	if (status != KERN_OK) {
 		kmsg_reply_error(msg, status, &msg_lock_flags);
 		return status;
@@ -208,17 +218,24 @@ extern kern_status_t channel_reply_msg(
 	/* the task that is about to send the response */
 	struct task *sender = self->tr_parent;
 
+	struct vm_region *src = sender->t_address_space,
+			 *dst = receiver->t_address_space;
+	unsigned long f;
+	vm_region_lock_pair_irqsave(src, dst, &f);
+
 	kern_status_t status = vm_region_memmove_v(
-		receiver->t_address_space,
+		dst,
 		0,
 		msg->msg_resp.msg_data,
 		msg->msg_resp.msg_data_count,
-		sender->t_address_space,
+		src,
 		0,
 		resp->msg_data,
 		resp->msg_data_count,
 		VM_REGION_COPY_ALL,
 		NULL);
+	vm_region_unlock_pair_irqrestore(src, dst, f);
+
 	if (status != KERN_OK) {
 		kmsg_reply_error(msg, status, &msg_lock_flags);
 		return status;
@@ -262,17 +279,24 @@ extern kern_status_t channel_read_msg(
 		return KERN_INVALID_ARGUMENT;
 	}
 
+	struct vm_region *src_region
+		= msg->msg_sender_thread->tr_parent->t_address_space;
+
+	unsigned long f;
+	vm_region_lock_pair_irqsave(src_region, dest_region, &f);
+
 	kern_status_t status = vm_region_memmove_v(
 		dest_region,
 		0,
 		dest_iov,
 		dest_iov_count,
-		msg->msg_sender_thread->tr_parent->t_address_space,
+		src_region,
 		offset,
 		msg->msg_req.msg_data,
 		msg->msg_req.msg_data_count,
 		VM_REGION_COPY_ALL,
 		nr_read);
+	vm_region_unlock_pair_irqrestore(src_region, dest_region, f);
 
 	spin_unlock_irqrestore(&msg->msg_lock, msg_lock_flags);