Index: t_ptrace_wait.c
===================================================================
RCS file: /cvsroot/src/tests/lib/libc/sys/t_ptrace_wait.c,v
retrieving revision 1.106
diff -u -r1.106 t_ptrace_wait.c
--- t_ptrace_wait.c	11 Apr 2019 19:25:31 -0000	1.106
+++ t_ptrace_wait.c	11 Apr 2019 20:07:45 -0000
@@ -3784,7 +3784,11 @@
 		i = 0;
 		/* Read the whole AUXV vector, it has no clear length */
 		while (errno != EIO) {
+#ifdef __MACHINE_STACK_GROWS_UP
+			io.piod_offs = (void *)(intptr_t)(-(ssize_t)sizeof(int) - i);
+#else
 			io.piod_offs = (void *)(intptr_t)i;
+#endif
 			SYSCALL_REQUIRE(ptrace(PT_IO, child, &io, sizeof(io))
 			                != -1 || (errno == EIO && i > 0));
 			++i;