/lib/modules/4.4.0-87-generic/kernel/arch/ is in linux-image-extra-4.4.0-87-generic 4.4.0-87.110~14.04.1.
This file is owned by root:root, with mode 0o755.
..
/lib/modules/4.4.0-87-generic/kernel/arch/x86/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/crypto/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/crypto/sha-mb/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/kernel/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/kernel/cpu/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/kernel/cpu/mcheck/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/kvm/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/oprofile/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/platform/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/platform/atom/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/platform/atom/punit_atom_debug.ko
/lib/modules/4.4.0-87-generic/kernel/arch/x86/ras/
/lib/modules/4.4.0-87-generic/kernel/arch/x86/ras/mce_amd_inj.ko