lsmod

Updated

September 4, 2026

Overview

lsmod lists loaded kernel modules (name, size, use count, dependents). It is a thin, readable view of /proc/modules. Use it when debugging drivers, missing hardware support, or before modprobe/rmmod operations.

Syntax

lsmod
# no significant options — see modprobe/rmmod for management

Examples with Explanations

List modules

lsmod
lsmod | sort
lsmod | head

Search for a driver

lsmod | grep -i usb
lsmod | grep -i nvidia
lsmod | grep -E '^(nfs|overlay|br_netfilter)'

Dependency / use count

lsmod | awk 'NR==1 || $3>0 {print}'
# third column: used by count; Used by column shows dependents

Correlate with hardware

lsusb
lspci -k
lsmod | grep -i xhci

lspci -k shows which kernel driver is bound to a PCI device.

Module details

modinfo e1000e
modprobe -n -v e1000e          # dry-run
cat /proc/modules | grep e1000e

Unload safety check

lsmod | grep module_name
sudo modprobe -r module_name   # preferred over raw rmmod
# fails if in use — check dependents in lsmod

Blacklist context

lsmod | grep nouveau
# if you blacklisted a module, it should not appear after reboot
grep -r nouveau /etc/modprobe.d/ 2>/dev/null

Understanding columns

Column	Meaning
Module	Module name
Size	Memory size in bytes
Used by	Reference count and dependent module names

A non-zero use count means unload will fail until dependents release it.

Notes / Pitfalls

Built-in kernel features are not modules — absence from lsmod doesn’t mean “unsupported”.
Out-of-tree modules (ZFS, some NVIDIA) still appear when loaded.
Containers usually cannot load modules; operations need host privileges.
Secure Boot may restrict unsigned modules.
Don’t randomly rmmod storage/network drivers on remote hosts.

2026-relevant notes

Initramfs and UKI images embed critical modules — lsmod after boot is not the whole story.
Prefer modprobe over insmod for dependency resolution.
For policy, use /etc/modules-load.d/ and /etc/modprobe.d/ rather than ad-hoc loads.

Additional Resources

man lsmod, man 5 modules