syscall: the signal received during system call processing is not processed.

Refs: #1176
Fujitsu: POSTK_DEBUG_TEMP_FIX_56
Change-Id: I410160ccbcef3ef49a0e37611a608bc87c97e63b

arch/x86_64/kernel/syscall.c

@@ -1001,6 +1001,11 @@ getsigpending(struct thread *thread, int delflag){
 struct sig_pending *
 hassigpending(struct thread *thread)
 {
+	if (list_empty(&thread->sigpending) &&
+	    list_empty(&thread->sigcommon->sigpending)) {
+		return NULL;
+	}
+
 	return getsigpending(thread, 0);
 }
 
@@ -1057,6 +1062,11 @@ check_signal(unsigned long rc, void *regs0, int num)
 		goto out;
 	}
 
+	if (list_empty(&thread->sigpending) &&
+	    list_empty(&thread->sigcommon->sigpending)) {
+		goto out;
+	}
+
 	for(;;){
 		pending = getsigpending(thread, 1);
 		if(!pending) {