On Wed, 2021-01-20 at 11:27 +0900, Hajime Tazaki wrote:

 static irqreturn_t um_timer(int irq, void *dev)
 {
+#ifndef CONFIG_UMMODE_LIB
 	if (get_current()->mm != NULL)

Why is the ifdef needed - get_current()->mm should always be NULL for
LKL? Surely get_current() must still work?

 	sigemptyset(&sig_mask);
 	sigaddset(&sig_mask, sig);
-	if (sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
-		panic("sigprocmask failed - errno = %d\n", errno);
+	if (pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
+		panic("pthread_sigmask failed - errno = %d\n", errno);

UML doesn't normally link with libpthread, and LKL doesn't actually
appear to require it either (since it has its lkl_thread and all), so
this seems wrong?

johannes