diff --git a/src/sem/ntapi_sem_query.c b/src/sem/ntapi_sem_query.c
index f1e53a9..1a6b2e2 100644
--- a/src/sem/ntapi_sem_query.c
+++ b/src/sem/ntapi_sem_query.c
@@ -15,12 +15,18 @@
 #include "ntapi_impl.h"
 
 static int32_t __sem_query_return(
+	void *		mapaddr,
 	intptr_t *	hlock,
 	int32_t		status)
 {
 	if (hlock)
 		at_store(hlock,0);
 
+	if (mapaddr)
+		__ntapi->zw_unmap_view_of_section(
+			NT_CURRENT_PROCESS_HANDLE,
+			mapaddr);
+
 	return status;
 }
 
@@ -32,6 +38,7 @@ int32_t	__stdcall __ntapi_sem_query(
 	__in	int32_t			sem_ipc_cmd)
 {
 	int32_t			status;
+	void *			mapaddr;
 	void *			hsection;
 	void *			secaddr;
 	size_t			secsize;
@@ -65,17 +72,23 @@ int32_t	__stdcall __ntapi_sem_query(
 			hsection = sem->section;
 			secaddr  = sem->section_addr;
 			secsize  = sem->section_size;
+			mapaddr  = 0;
 
 		} else if ((status = __ntapi->ipc_init_section_by_port(
 				sem->hport,&hsection,
 				&secaddr,&secsize)))
 			return status;
 
+		else
+			mapaddr = secaddr;
+
 		/* lock */
 		hlock = &(__ntapi_internals()->hlock);
 
 		if (at_locked_cas(hlock,0,1))
-			return NT_STATUS_RESOURCE_NOT_OWNED;
+			return __sem_query_return(
+				mapaddr,0,
+				NT_STATUS_RESOURCE_NOT_OWNED);
 	}
 
 	/* msg */
@@ -95,15 +108,15 @@ int32_t	__stdcall __ntapi_sem_query(
 	msg.data.seminfo.section_size	= secsize;
 
 	if ((status = __ntapi->zw_request_wait_reply_port(sem->hport,&msg,&msg)))
-		return __sem_query_return(hlock,status);
+		return __sem_query_return(mapaddr,hlock,status);
 	else if (msg.data.ttyinfo.status)
-		return __sem_query_return(hlock,msg.data.ttyinfo.status);
+		return __sem_query_return(mapaddr,hlock,msg.data.ttyinfo.status);
 
 	/* reply */
 	if (sem_ipc_cmd == NT_SEM_CMD_GETALL) {
 		if (msg.data.seminfo.section_size > sem_info_length)
 			return __sem_query_return(
-				hlock,
+				mapaddr,hlock,
 				NT_STATUS_BUFFER_TOO_SMALL);
 
 		__ntapi->tt_generic_memcpy(
@@ -114,6 +127,11 @@ int32_t	__stdcall __ntapi_sem_query(
 
 		iosb->status = NT_STATUS_SUCCESS;
 		iosb->info   = msg.data.seminfo.section_size;
+
+		if (mapaddr)
+			__ntapi->zw_unmap_view_of_section(
+				NT_CURRENT_PROCESS_HANDLE,
+				mapaddr);
 	} else {
 		if (msg.header.data_size != sizeof(msg.data))
 			return NT_STATUS_UNEXPECTED_IO_ERROR;