Question

This architecture does not have kernel memory protection.
Run /linuxrc as init process
process '/bin/busybox' started with executable stack

Answer1

busybox.fragment

@@ -74,3 +74,5 @@ CONFIG_FEATURE_REMOTE_LOG=y
 CONFIG_BB_SYSCTL=y
 CONFIG_SED=y
 CONFIG_FEATURE_SHOW_THREADS=y
+CONFIG_EXTRA_CFLAGS="-Wl,-z,noexecstack"
+CONFIG_EXTRA_LDFLAGS="-Wl,-z,noexecstack"

Answer2

$ sudo apt install execstack
$ execstack busybox		# check
X busybox

$ execstack -c busybox	# clear execstack