Bug 1027600 - [RFE][rmmod] if module is in used, rmmod output the dependences
Summary: [RFE][rmmod] if module is in used, rmmod output the dependences
Keywords:
Status: CLOSED CANTFIX
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: kmod
Version: 7.0
Hardware: All
OS: Linux
unspecified
medium
Target Milestone: rc
: ---
Assignee: Václav Pavlín
QA Contact: Red Hat Kernel QE team
URL:
Whiteboard:
Depends On:
Blocks: 1027601
TreeView+ depends on / blocked
 
Reported: 2013-11-07 08:09 UTC by JianHong Yin
Modified: 2013-12-16 15:15 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Enhancement
Doc Text:
Clone Of:
: 1027601 (view as bug list)
Environment:
Last Closed: 2013-12-16 15:15:40 UTC
Target Upstream Version:


Attachments (Terms of Use)

Description JianHong Yin 2013-11-07 08:09:50 UTC
Description of problem:
When we want rmmod the nfsd, the rmmod just tell me module "is in use".
  But not tell me who use it.
[root@dhcp12-144 ~]# rmmod nfsd
rmmod: ERROR: Module nfsd is in use   <<<--- NOT GOOD
[root@dhcp12-144 ~]# rmmod auth_rpcgss
rmmod: ERROR: Module auth_rpcgss is in use by: nfsd   <<<--- GOOD

And my buddy cost more than half an hours to find why can not rmmod,
  Finally we find it used by /proc/fs/nfsd.
Could rmmod output the dependences, if the dependences is not module name?

Version-Release number of selected component (if applicable):
all version in RHEL{5,6,7}

How reproducible:
100%

Steps to Reproduce:
1. rmmod nfsd
2.
3.

Actual results:
[root@dhcp12-144 ~]# rmmod nfsd
rmmod: ERROR: Module nfsd is in use 

Expected results:
[root@dhcp12-144 ~]# rmmod nfsd
rmmod: ERROR: Module nfsd is in use "by: /proc/fs/nfsd"
OR like follow (if difficult to get):
rmmod: ERROR: Module nfsd is in use "by: nil(maybe used by special filesystem)"

Additional info:

Comment 2 Václav Pavlín 2013-12-12 09:16:05 UTC
I am afraid this is not possible. As rmmod can only get the idea whether the module is used or not from refcnt (/sys/module/nfsd/refcnt), which is set by kernel, I don't see any option how to get the information what is actually using the module.

CC'ing Josh Boyer for his opinion.

Comment 3 Josh Boyer 2013-12-12 14:02:12 UTC
I agree with Václav.  The only things rmmod/modprobe have to look at are the refcnt and the module dependency list (holders).  If a module has its refcnt incremented by something other than another module, there is no simple way for rmmod/modprobe -r to determine that.

Comment 4 Václav Pavlín 2013-12-16 15:15:40 UTC
So closing as CANTFIX.


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