Index: sys/arch/mips/mips/syscall.c
===================================================================
RCS file: /cvsroot/src/sys/arch/mips/mips/syscall.c,v
retrieving revision 1.49
diff -p -u -r1.49 syscall.c
--- sys/arch/mips/mips/syscall.c	31 Jul 2016 07:06:24 -0000	1.49
+++ sys/arch/mips/mips/syscall.c	26 Oct 2016 09:23:38 -0000
@@ -264,6 +264,9 @@ EMULNAME(syscall)(struct lwp *l, u_int s
 				copyargs[i++] = (int32_t) arg;
 				arg64mask >>= 1;
 				continue;
+			} else {
+				if ((i & 1) != 0)
+					continue;
 			}
 			/*
 			 * 64bit arg.  grab the low 32 bits, discard the high.