Bug 83599 - Two users can not change their password at the same time
Summary: Two users can not change their password at the same time
Alias: None
Product: Red Hat Enterprise Linux 2.1
Classification: Red Hat
Component: passwd
Version: 2.1
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Tomas Mraz
QA Contact:
Depends On:
TreeView+ depends on / blocked
Reported: 2003-02-06 01:31 UTC by Andrew Garvin
Modified: 2007-11-30 22:06 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2005-03-25 09:51:13 UTC
Target Upstream Version:

Attachments (Terms of Use)

Description Andrew Garvin 2003-02-06 01:31:29 UTC
Description of problem:
Two users can not change their password at the same time.

Version-Release number of selected component (if applicable):
passwd-0.64.1-7 on RedHat Advanced Server 2.1 (with all errata updates)

How reproducible:
100% reproducible

Steps to Reproduce:
1. Login as a user (other than root).
2. Type passwd.  Then do not type anything.
3. Login again as any user.
4. Type passwd.
Actual results:
The second time you type passwd, nothing happens.  As soon as the first user 
finishes changing their password, the second user is able to change their 

Expected results:
How can RedHat Advanced Server be advertised as an "Enterprise" product if you 
can not do something as simple as having two users change their password at the 
same time???  This also applies to users who have their password expired.  
After they login they are forced to change their password, but if someone else 
is changing their password at that time, all that user can do is just sit there 
and wait their turn.  This is a HUGE problem for us because we are about to go 
live on a 1000+ user (400+ concurrent) order entry server.  This password 
change problem is unacceptable.  If a solution can not be found, I will be 
forced to look for an alternative OS.  In my opinion this should be a top 
priority for RedHat.  We are planning on going live with this new server in the 
next couple of weeks, so a quick response would be appreciated.

Additional info:
This does not apply to root.  The root user can have as many passwd sessions 
opened as needed.  I have also verified that this is true on RedHat 7.2, 7.3, 
and 8.0.

Comment 1 Andrew Garvin 2003-03-25 20:19:48 UTC
Hello????  Anyone out there?????

Can I get an update on this?  Can anyone else confirm there is a problem here?  
Is there a fix in the works?

Comment 6 Pete Palmer 2004-08-02 18:39:57 UTC
The problem seems to be with a file called /etc/.pwd.lock 

This file is created when a user tries to change their password :

-rw-------    1 root     amy             0 Aug  2 19:24 .pwd.lock

As you can see, only root can access the file despite the fact 
they've gone to the trouble to set the group. As RH uses "private 
groups" it is normal for the username to match the groupname. I 
imagine this is used to determine which user is changing their 

Unfortunately whilst this file exists, normal users cannot change 
their own passwords. Instead the passwd program sits and waits for 
the previous program to finish running. The other users password 
prompt then carries on as normal.

I'm currently investigating what part the lock file plays in the 
password change process to see whether or not this problem can be 
easily solved.

Comment 7 Malcolm 2004-08-04 08:57:43 UTC
just to add a bit of weight; 
AFAIK, this has been a problem since RHL 6.2 (or earlier) and affects
Fedora also (but not Debian or Slackware) 

we now have a customer, where this fix is on the critical path, RHEL4 ?

Comment 8 Tomas Mraz 2005-03-25 09:51:13 UTC
This is fixed through the latest RHEL 2.1 pam errata.

Comment 9 Andrew Garvin 2005-03-25 21:59:53 UTC
Does that mean that it is fixed in RHEL 3 and RHEL4 as well?  Do those versions 
require a patch to pam as well to make this work?  What specific patch level is 
required for the fix?

Comment 10 Tomas Mraz 2005-03-27 16:33:14 UTC
Yes, it is fixed in RHEL4 and in RHEL3 U4.

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