How to see kernel modules information and load/unload kernel modules in Linux or solaris ?
Kernel Module Loading/Unloading in Linux
Lets see how to view kernel modules in linux and how can we load or unload a module in linux.
1. View all modules available on system
We can view all available modules on a Linux system using “modprobe -l” command.
[root@nglinux ~]# modprobe -l | more kernel/arch/x86/kernel/cpu/mcheck/mce-inject.ko kernel/arch/x86/kernel/cpu/cpufreq/powernow-k8.ko kernel/arch/x86/kernel/cpu/cpufreq/mperf.ko kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko kernel/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.ko kernel/arch/x86/kernel/cpu/cpufreq/p4-clockmod.ko
2. View currently loaded modules on system
To see the currently loaded modules on system, we can use lsmod command.
[root@nglinux ~]# lsmod Module Size Used by bnx2fc 80024 0 cnic 47474 1 bnx2fc uio 7822 1 cnic fcoe 19570 0 libfcoe 47527 2 bnx2fc,fcoe libfc 96173 3 bnx2fc,fcoe,libfcoe scsi_transport_fc 43160 3 bnx2fc,fcoe,libfc 8021q 16617 0 scsi_tgt 9933 1 scsi_transport_fc garp 5703 1 8021q stp 1626 1 garp llc 4226 2 garp,stp ipt_REJECT 1899 1 nf_conntrack_ipv4 7374 2 nf_defrag_ipv4 1039 1 nf_conntrack_ipv4 iptable_filter 2173 1 ip_tables 9599 1 iptable_filter ip6t_REJECT 3731 2 nf_conntrack_ipv6 6588 3 nf_defrag_ipv6 16175 1 nf_conntrack_ipv6
3. Viewing details of individual module.
To view details of a module, we can use modinfo command followed by module name.
### lets see ip_tables module detail [saket@ngelinux-new ~]$ modinfo ip_tables filename: /lib/modules/2.6.32-696.el6.i686/kernel/net/ipv4/netfilter/ip_tables.ko description: IPv4 packet filter author: Netfilter Core Team < coreteam@netfilter.org > license: GPL srcversion: D97231A516F24FDE3206537 depends: vermagic: 2.6.32-696.el6.i686 SMP mod_unload modversions 686 [saket@ngelinux-new ~]$
4. Adding a module
To load a module, simply mention the module name with modprobe command.
[root@nglinux ~]#modprobe -v ip_tables [root@nglinux ~]#
5. Check the loaded module
We can check if the module gets loaded by using lsmod command.
[root@nglinux ~]#lsmod | grep -i ip_tables ip_tables 9599 1 iptable_filter
6. Removing a module
To remove a module, we can use “-r” switch of modprobe command.
[root@nglinux ~]#modprobe -r ip_tables FATAL: Module ip_tables is in use. [root@nglinux ~]#modprobe -rf ip_tables FATAL: Module ip_tables is in use.
7. Load a module with different name
We can also load a module using some other name, in case its conflicting with some other module.
However sometimes it doesn’t work.
[root@nglinux ~]# modprobe -v nfs -o nfs_ngel_service
install /sbin/modprobe --first-time --ignore-install sunrpc && { /bin/mount -t rpc_pipefs sunrpc /var/lib/nfs/rpc_pipefs > /dev/null 2>&1 || :; }
insmod /lib/modules/2.6.32-696.el6.i686/kernel/net/sunrpc/sunrpc.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/nfs_common/nfs_acl.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/net/sunrpc/auth_gss/auth_rpcgss.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/fscache/fscache.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/lockd/lockd.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/nfs/nfs.ko
FATAL: Error inserting nfs (/lib/modules/2.6.32-696.el6.i686/kernel/fs/nfs/nfs.ko): Key was rejected by service
Some kernels don’t take new module name, and hence we need to load it by original name.
[root@nglinux ~]# modprobe -v nfs
install /sbin/modprobe --first-time --ignore-install sunrpc && { /bin/mount -t rpc_pipefs sunrpc /var/lib/nfs/rpc_pipefs > /dev/null 2>&1 || :; }
insmod /lib/modules/2.6.32-696.el6.i686/kernel/net/sunrpc/sunrpc.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/nfs_common/nfs_acl.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/net/sunrpc/auth_gss/auth_rpcgss.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/fscache/fscache.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/lockd/lockd.ko
insmod /lib/modules/2.6.32-696.el6.i686/kernel/fs/nfs/nfs.ko
[root@nglinux ~]#
Loding/Unloading Modules on Solaris
On solaris, we can do the same tasks using below commands.
1. Check all modules of the system
# modinfo | more
2. View specific details of module.
# modinfo | grep -i scsi
3. Loading a module.
# modload -i 27
4. Unloading a module
# modunlod -i 27
Now you can load/unload a module in Linux/Solaris.
Do post your valuable comments or questions below.