How to determine if a specific module is loaded in linux kernel

Question

I am just curious is there any way to determine if a particular module is loaded/installed.

$ lsmod lists all modules (device driver loaded).

Is there any way to check or a command that returns true/false boolean output if a module name is polled. For eg. if keyboard.o exists return true else false. I need this tip to complete my driver auto refresh program.

PS: tried modinfo. I am using busybox client in my test DUT so can you give some alternatives other than modinfo?

The question is a bit ambiguous. Are you trying to check if the driver is loaded into memory or installed on the system? modinfo would help with the latter but not the former. — presto8, Jul 16 '13 at 22:31

score 44 · Answer 1 · edited Dec 24 '22 at 05:58

44

The modinfo module method does not work well for me. I prefer this method that is similar to the alternative method proposed:

#!/bin/sh

MODULE="$1"

if lsmod | grep -wq "$MODULE"; then
  echo "$MODULE is loaded!"
  exit 0
else
  echo "$MODULE is not loaded!"
  exit 1
fi

edited Dec 24 '22 at 05:58

hansfn

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answered Dec 21 '12 at 17:55

basfest

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`grep -Eq "^${MODULE} ";` – Ciro Santilli OurBigBook.com Jul 29 '16 at 20:10
3

`grep -wq "^${MODULE}"` to catch the word – ykhrustalev Jan 02 '20 at 13:28

score 28 · Accepted Answer · edited Mar 26 '12 at 16:24

28

not sure if modinfo modname and checking $? will work for you, just a suggestion.

/tmp$ sudo modinfo e1000
/tmp$ echo $?
0
/tmp$ sudo modinfo keyboard
ERROR: modinfo: could not find module keyboard
/tmp$ echo $?
1

alternatively you also grep /proc/modules

edited Mar 26 '12 at 16:24

Shawn Chin

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answered Mar 23 '12 at 20:13

johnshen64

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Just a note: the `modinfo` approach doesn't seem to actually work for the _loaded_ check (as in the question title). It shows info regardless of whether the module is loaded. – BeeOnRope Nov 14 '16 at 18:26
2

This is not a good solution. modinfo shows information of a kernel module installed on the rootfs, but it doesn't check if the module is loaded into the kernel or not. So this solution should not be used to solve the issue. – aicastell Aug 27 '20 at 08:33
3

Only `lsmod` and `/proc/modules` show what modules are **loaded**. – CMCDragonkai Sep 09 '20 at 12:56

Julia Path · Answer 3 · 2017-12-03T16:28:45.327

18

The --first-time flag causes modprobe to fail if the module is already loaded. That in conjunction with the --dry-run (or the shorthand -n) flag makes a nice test:

modprobe -n --first-time $MODULE && echo "Not loaded" || echo "Loaded"

Edit 1: As @Nobody pointed out this also prints Loaded if the module does not exist. We can fix this by combining it with modinfo:

modinfo $MODULE >/dev/null 2>/dev/null &&
! modprobe -n --first-time $MODULE 2>/dev/null &&
echo "Loaded" || echo "Not loaded"

Edit 2: On some systems modprobe lives in /usr/sbin, which is not in the $PATH unless you are root. In that case you have to substitute modprobe for /usr/sbin/modprobe in the above.

edited Dec 03 '17 at 16:28

answered May 18 '15 at 19:50

Julia Path

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Problem: Needs root and when you enter bullshit for $MODULE it claims that $MODULE is loaded. – Nobody Nov 15 '16 at 16:05
@Nobody It does not require root on my system. – Julia Path Dec 03 '17 at 13:13
2

Oh, sorry, I was only half-right (or maybe quarter-right. Shame on you comment-up-voters). On Debian, modprobe is not in $PATH for normal users, so just copy&pasting your command only works as root. But when calling modprobe with its full path, it's executable for normal users and only the actual inserting operation fails, so your solution works in principle. I still think querying /proc/modules is more elegant, but that's a matter of taste. Had I downvoted your answer, I would have removed the vote now (but I didn't). – Nobody Dec 03 '17 at 13:30

Nobody · Answer 4 · 2017-12-03T19:37:27.827

I wrote this:

MODULE=snd_aloop # for example
test -n "$(grep -e "^$MODULE " /proc/modules)" && echo "Loaded" || echo "Not loaded"

It checks in /proc/modules. If the module is mentioned there, it's assumed to be loaded, otherwise not.

The others seemed too long to me (the other short one requires root, this does not). Of course it's just written out what was already mentioned as "alternatives".

Caution: modprobe accepts some variants of module names other than the primary listed in /proc/modules. For example loading snd-aloop works, but the module is named snd_aloop and is listed as such in /proc/modules and when using rmmod that's also the only name that will work.

You may want to match for `"^$MODULE\>"` instead to make sure you aren't matching just part of the module name. — Julia Path, Dec 03 '17 at 16:23

1000Gbps · Answer 5 · 2020-10-05T21:31:14.373

9

My short way to find if a given module is actually loaded:

cat /proc/modules | grep -c nfnetlink

which outputs

That 2 (TWO) means the module is LOADED. The actual output without -c shows all loaded modules with MODULENAME - -c counts the lines that contain MODULENAME. So if you have 0 (ZERO) lines as output then the module is not loaded

edited Oct 05 '20 at 21:31

answered Oct 05 '20 at 21:25

1000Gbps

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You can use it with if. `if cat /proc/modules | grep -c nfnetlink; then echo "module loaded" fi` – Abc Xyz Oct 10 '20 at 13:17

Mostafa Barmshory · Answer 6 · 2020-01-05T16:22:52.357

7

The better idea is to create a bash function:

#!/bin/sh
function moduleExist(){
  MODULE="$1"
  if lsmod | grep "$MODULE" &> /dev/null ; then
    return 0
  else
    return 1
  fi
}


if moduleExist "module name"; then
  #do somthing
fi

edited Jan 05 '20 at 16:22

answered Sep 27 '14 at 08:16

Mostafa Barmshory

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What difference is there from @basfest's answer? – Jonathan Lam Jan 05 '20 at 03:48
Dear @JonathanLam, I try to convert the code into a simple function and reuse it in my sell script. As you can see the condition expression is readable. – Mostafa Barmshory Jan 05 '20 at 16:25

score 2 · Answer 7 · edited May 15 '14 at 20:49

2

 !/bin/sh
 # Module
 MODULE="scsi_dh_rdac"

 #Variables check if module loaded or not
 MODEXIST=/sbin/lsmod | grep "$MODULE"

 if [ -z "$MODEXIST" ]; then
       /sbin/modprobe "$MODULE" >/dev/null 2>&1
 fi

edited May 15 '14 at 20:49

Santosh Joshi

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answered May 15 '14 at 20:27

ronald

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Although your answer looks good, you should include a little explanation... plain code may be good, but code *and* explanation is better – Barranka May 15 '14 at 21:05

score 0 · Answer 8 · answered Oct 22 '19 at 04:15

0

module list

Returns:

Currently Loaded Modulefiles:
  1) /coverm/0.3.0        2) /parallel/20180222

answered Oct 22 '19 at 04:15

MeggyClay

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Where did you get `module` from...? – usretc Dec 21 '20 at 20:08

score 0 · Answer 9 · answered Dec 21 '20 at 20:14

0

grep -wEq "^${module%.o}" /proc/modules

returns true (e.g. can be used in an if) whether you ask for keyboard or keyboard.o

answered Dec 21 '20 at 20:14

usretc

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score 0 · Answer 10 · answered Apr 14 '22 at 00:21

0

grep -q $pattern against lsmod or /proc/modules, which are available on most systems and a standard "source of truth"

lsmod | grep -q $pattern

$ lsmod | grep -q msr
$ echo $?
0

$ lsmod | grep -q duediligencemuch
$ echo $?
1

answered Apr 14 '22 at 00:21

why so serious

11
2

How to determine if a specific module is loaded in linux kernel

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