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Bug 500693

Summary: LTP ftest04 and ftest08 Failures
Product: Red Hat Enterprise Linux 5 Reporter: Qian Cai <qcai>
Component: kernelAssignee: Cong Wang <amwang>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.3CC: drepper, dzickus, emcnabb, rkhan, syeghiay
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-09-02 08:38:30 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:
Attachments:
Description Flags
simpler reproducer none

Description Qian Cai 2009-05-13 17:51:37 UTC
Created attachment 343828 [details]
simpler reproducer

Description of problem:
Those tests are forking several processes to do a random lseek each, and
read/write a chunk of data to the same file.

The failure messages are like the following,

# ./ftest04
ftest04     1  FAIL  :  Test[1]: xfr=1920 != 2048, zero read.
ftest04     1  FAIL  :  Expected 0 exit status - failed.
ftest04     2  FAIL  :  Test failed.

This is because one of children is doing,

lseek64(fd, 534528);

readv(fd, buf[2048/16], 16);

but readv() only returns less than 16 chunks of data. If I replace the
above call with,

read(fd, buf, 2048);

It seems work just fine.

I can always reproduce this on at least 2 x86-64 machines with both
-128.el5 and -141.el5 kernels.
- bigisis.rhts.bos.redhat.com
- gs-bl460cg1-01.rhts.bos.redhat.com

In additions, upstream kernel seems not affected by this by running the
simpler reproducer attached more than 7000 times.
# uname -a
Linux nec-em18.rhts.bos.redhat.com 2.6.27.5-117.fc10.x86_64 #1 SMP Tue
Nov 18 11:58:53 EST 2008 x86_64 x86_64 x86_64 GNU/Linux
# rpm -q glibc
glibc-2.9-2.x86_64

Version-Release number of selected component (if applicable):
# rpm -q glibc
glibc-2.5-34

How reproducible:
Usually failed within 200 times by running the simpler reproducer in a loop.

Steps to Reproduce:
1. gcc readv.c -o readv
2. t=1; while :; do t=$((t + 1)); ./readv; if [ $? -ne 0 ]; then break; fi; echo $t; done
  
Actual results:
...
201
Test[3]: xfr=640 != 2048, zero read.
Expected 0 exit status - failed.
Test failed.

Expected results:
Always pass.

Additional information:
This does not look like 64-bit only problem, because after compiled the simpler reproducer using,
gcc -m32 readv.c -o readv

It can reproduce the same problem.

Comment 3 RHEL Program Management 2009-07-02 17:43:54 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.

Comment 5 Don Zickus 2009-07-07 15:05:03 UTC
in kernel-2.6.18-157.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.

Comment 9 errata-xmlrpc 2009-09-02 08:38:30 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/RHSA-2009-1243.html