Bug 1437014

Summary: lsof -nP is unusable on EL7 when a multi threaded process has many files open
Product: Red Hat Enterprise Linux 7 Reporter: Marcus Sundberg <devel>
Component: lsofAssignee: Jan Rybar <jrybar>
Status: CLOSED ERRATA QA Contact: Jakub Heger <jheger>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.3CC: bsingh, djez, fkrska, mkyral, mowens, smeyer
Target Milestone: rcKeywords: Patch, Upstream
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: lsof-4.87-6.el7 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of:
: 1437018 (view as bug list) Environment:
Last Closed: 2018-10-30 07:56:27 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1473612, 1549617, 1549689, 1551061    
Attachments:
Description Flags
Sample program to illustrate the problem.
none
Patch to only list threads/tasks if the -K flag is given.
none
Proposed backport patch none

Description Marcus Sundberg 2017-03-29 09:40:13 UTC
Description of problem:
When there is at least one process in the system running that has many
open file descriptors and many threads lsof -nP takes a a lot of time
to run and produces huge output.

Version-Release number of selected component (if applicable):
lsof-4.87-4.el7.x86_64

How reproducible: Always

Steps to Reproduce:
1. lsof -nP

Actual results:
Takes a long time to traverse all threads of all processes.

Expected results:
Only traverse processes, unless -K flag is given.

Comment 2 Marcus Sundberg 2017-03-29 09:41:57 UTC
Created attachment 1267267 [details]
Sample program to illustrate the problem.

Comment 3 Marcus Sundberg 2017-03-29 09:44:56 UTC
Created attachment 1267268 [details]
Patch to only list threads/tasks if the -K flag is given.

Comment 4 Marcus Sundberg 2017-03-29 09:46:15 UTC
Example running standard and patches lsof in an EL7 desktop session:

Standard EL7 lsof:
$) time lsof -nP | wc -c
14117646

real	0m1.430s
user	0m0.648s
sys	0m0.789s
$) ./fd-and-threads &
[1] 30452
$) time lsof -nP | wc -c
75110357

real	0m13.096s
user	0m4.128s
sys	0m8.968s
$) 

Patched lsof:
$) time lsof -nP | wc -c
1748246

real	0m0.214s
user	0m0.087s
sys	0m0.131s
$) ./fd-and-threads &
[1] 31585
$) time lsof -nP | wc -c
1822372

real	0m0.247s
user	0m0.087s
sys	0m0.162s
$) time lsof -nPK | wc -c
68403949

real	0m12.946s
user	0m4.125s
sys	0m8.828s
$)

Comment 9 Jan Rybar 2018-02-22 15:12:04 UTC
Created attachment 1399440 [details]
Proposed backport patch

Patch to ignore threads if -Ki flag is given. Change backported from upstream. lsof always displayed threads by default (documented in manpage).

Comment 15 errata-xmlrpc 2018-10-30 07:56:27 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:3046