diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 6a0e466..3492886 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -490,8 +490,8 @@
 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
 {
 	(*buf)[0].JB_IP = (unsigned long) handler;
-	(*buf)[0].JB_SP = (unsigned long) stack +
-		(PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) - sizeof(void *);
+	(*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
+		sizeof(void *);
 }
 
 #define INIT_JMP_NEW_THREAD 0
@@ -533,8 +533,7 @@
 	case INIT_JMP_NEW_THREAD:
 		(*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
 		(*switch_buf)[0].JB_SP = (unsigned long) stack +
-			(PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) -
-			sizeof(void *);
+			UM_THREAD_SIZE - sizeof(void *);
 		break;
 	case INIT_JMP_CALLBACK:
 		(*cb_proc)(cb_arg);