Is it possible your kernels are configured without ptys? Current Ubuntu kernels specify the following pty options:
CONFIG_UNIX98_PTYS=y CONFIG_LEGACY_PTYS=y CONFIG_LEGACY_PTY_COUNT=0
Is it possible your kernels are configured without ptys? Current Ubuntu kernels specify the following pty options:
CONFIG_ UNIX98_ PTYS=y LEGACY_ PTYS=y LEGACY_ PTY_COUNT= 0
CONFIG_
CONFIG_