Bug 151899

Summary: RHEL3: "lsof -b" hangs if a process is stuck in disk-wait
Product: Red Hat Enterprise Linux 3 Reporter: Karel Zak <kzak>
Component: lsofAssignee: Karel Zak <kzak>
Status: CLOSED WONTFIX QA Contact: Brock Organ <borgan>
Severity: medium Docs Contact:
Priority: medium    
Version: 3.0CC: jplans, syeghiay, tao
Target Milestone: ---Keywords: Reopened
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-07-10 12:53:34 UTC Type: ---
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: 190430    

Description Karel Zak 2005-03-23 11:50:51 UTC 
+++ This bug was initially created as a clone of Bug #131712 +++

Description of problem:
'lsof -b', hangs in disk-wait if another process is also stuck in
disk-wait.

Version-Release number of selected component (if applicable): 4.72-1

How reproducible: ~10-30% on first try.  Often takes several
iterations of step (4) below.

Steps to Reproduce:
1. Mount NFS export from another machine (hard mount, not soft)
2. cd /new_nfs_mount; while [ 0 ]; do find . ; done
3. Disable NFS export+ifdown interface and/or reboot NFS server 
4. Run 'lsof -b' on client

  
Actual results:
Step (4) hangs while doing stat64; lsof process goes into disk-wait:

read(4, "30030 (bash) S 30025 30030 30030"..., 4096) = 224
close(4)                                = 0
munmap(0xb7298000, 4096)                = 0
readlink("/proc/30030/cwd", "/mnt/tmp", 4096) = 8
stat64("/proc/30030/cwd",


Expected results:
No hang.


Additional info:
I tried the above steps with the following combinations, all hung
after a few tries.

RHEL 2.1 + lsof 4.52
RHEL 2.1 + lsof 4.63
RHEL 3 + lsof 4.63
RHEL 3 + lsof 4.72
Fedora Core 2 + lsof 4.72

Could it possibly a kernel bug?  The original process goes into disk
wait, while 'lsof -b' subsequently succeeds a few times (usually)
before hanging.
Comment 4 Karel Zak 2005-05-11 08:33:58 UTC 
Test package: 
http://people.redhat.com/kzak/lsof/bz151899/lsof-4.63-4.1.1.testonly.src.rpm
Comment 22 Issue Tracker 2007-07-02 14:17:31 UTC 
Closing this one as it has been agreed to close all RHEL3 issues.

Internal Status set to 'Resolved'
Status set to: Closed by Client
Resolution set to: 'Closed by Client'
Ticket type set to: 'Question'

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