Bug 660319

Summary: In ksh scripts, files may be created but then fail to be immediately opened.
Product: Red Hat Enterprise Linux 6 Reporter: Michal Hlavinka <mhlavink>
Component: kshAssignee: Michal Hlavinka <mhlavink>
Status: CLOSED ERRATA QA Contact: BaseOS QE - Apps <qe-baseos-apps>
Severity: medium Docs Contact:
Priority: medium    
Version: 6.0CC: kvolny, mbelangia, mfranc, ovasik
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
When a ksh script created a file and immediately opened it after the creation, the operation failed. This happened because the created file, in some cases, did not exist yet. With this update, this race condition has been fixed and once a file is created, it is immediately available for any following commands.
 Story Points: ---
Clone Of: 659459 Environment:
Last Closed: 2011-05-19 13:50:25 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: 659459    
Bug Blocks:    
Attachments:
Description Flags
patch to fix this jskala: review+

Description Michal Hlavinka 2010-12-06 14:16:21 UTC 
+++ This bug was initially created as a clone of Bug #659459 +++

Created attachment 464363 [details]
Reproduction script

Description of problem:

When creating a file inside a ksh script and then immediately attempting to open the new file the file does not exist.  This occurs even when the file creation is inside parentheses and the access occurs outside the parentheses and the filesystem is on a local disk.

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

Client is reporting against 20100202-1.el5 (RHEL5) but I have also reproduced on 20100202-1.el5_5.1 (RHEL5).  This is also reproducable on 20100621-1.fc13 (Fedora 13) but seems to require more iterations.

How reproducible:

Attached are two files.  The first, ksh.bug, is a script which will reproduce the error.  The second, ksh.strace.out, is an strace of a failed run.  Search for "###" in the strace to find annotations displaying the failure

Steps to Reproduce:
1. Run ksh.bug

  
Actual results:
It seems that commands are being evaluated in an incorrect order.


Expected results:
As I understand it, the commands inside the parentheses should always be completed before the following commands are executed.
Comment 2 Michal Hlavinka 2011-01-05 13:31:39 UTC 
Created attachment 471863 [details]
patch to fix this
Comment 5 Martin Prpič 2011-03-16 15:59:33 UTC 
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
When a ksh script created a file and immediately opened it after the creation, the operation failed. This happened because the created file, in some cases, did not exist yet. With this update, this race condition has been fixed and once a file is created, it is immediately available for any following commands.
Comment 6 errata-xmlrpc 2011-05-19 13:50:25 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2011-0645.html