kernel: kproc error and exit

catch the error() that can be thrown by sleep() and tsleep()
in kprocs.

add missing pexit() calls.

always set the freemem argument to pexit() from kproc otherwise
the process gets added to the broken list.

sys/src/9/port/alarm.c

@@ -13,6 +13,9 @@ alarmkproc(void*)
 	Proc *rp;
 	ulong now;
 
+	while(waserror())
+		;
+
 	for(;;){
 		now = MACHP(0)->ticks;
 		qlock(&alarms);

sys/src/9/port/devaoe.c

@@ -701,8 +701,10 @@ loop:
 	}
 	runlock(&devs);
 	i = Nms - TK2MS(Ticks - starttick);
-	if(i > 0)
+	if(i > 0 && !waserror()){
 		tsleep(&up->sleep, return0, 0, i);
+		poperror();
+	}
 	goto loop;
 }
 

sys/src/9/port/devsdp.c

@@ -908,6 +908,8 @@ sdpackproc(void *a)
 	int i;
 	Conv *c;
 
+	while(waserror())
+		;
 	for(;;) {
 		tsleep(&up->sleep, return0, 0, 1000);
 		sec = TK2SEC(m->ticks);

sys/src/9/port/devsegment.c

@@ -530,6 +530,8 @@ segmentkproc(void *arg)
 	incref(g->s);
 	up->seg[sno] = g->s;
 
+	while(waserror())
+		;
 	for(done = 0; !done;){
 		sleep(&g->cmdwait, cmdready, g);
 		if(waserror()){
@@ -554,6 +556,8 @@ segmentkproc(void *arg)
 		g->cmd = Cnone;
 		wakeup(&g->replywait);
 	}
+
+	pexit("done", 1);
 }
 
 Dev segmentdevtab = {

sys/src/9/port/random.c

@@ -42,10 +42,11 @@ genrandom(void*)
 	up->basepri = PriNormal;
 	up->priority = up->basepri;
 
+	while(waserror())
+		;
 	for(;;){
-		for(;;)
+		if(++rb.randomcount <= 100000)
-			if(++rb.randomcount > 100000)
+			continue;
-				break;
 		if(anyhigher())
 			sched();
 		if(!rbnotfull(0))

sys/src/9/port/swap.c

@@ -147,12 +147,11 @@ pager(void *junk)
 	Segment *s;
 	Proc *p, *ep;
 
-	if(waserror())
-		panic("pager: os error");
-
 	p = proctab(0);
 	ep = &p[conf.nproc];
 
+	while(waserror())
+		;
 loop:
 	up->psstate = "Idle";
 	wakeup(&palloc.r);

sys/src/9/port/usbehci.c

@@ -2225,6 +2225,8 @@ ehcipoll(void* a)
 	hp = a;
 	ctlr = hp->aux;
 	poll = &ctlr->poll;
+	while(waserror())
+		;
 	for(;;){
 		if(ctlr->nreqs == 0){
 			if(0)ddprint("ehcipoll %#p sleep\n", ctlr->capio);