diff -r 0c163a8589a6 sys/src/cmd/upas/fs/fs.c
--- a/sys/src/cmd/upas/fs/fs.c	Mon Dec 10 05:18:05 2018 +0000
+++ b/sys/src/cmd/upas/fs/fs.c	Tue Dec 11 21:04:53 2018 -0800
@@ -679,11 +679,12 @@
 	case Qraw:
 		cacheheaders(mb, m);
 		p = m->start;
+		if(p)
 		if(strncmp(m->start, "From ", 5) == 0)
 		if(e = strchr(p, '\n'))
 			p = e + 1;
 		d->name = dirtab[t];
-		d->length = m->size - (p - m->start);
+		d->length = p ? m->size - (p - m->start) : 0;
 		putcache(mb, m);
 		break;
 	case Qrawbody: