Red Hat Bugzilla – Bug 500693
LTP ftest04 and ftest08 Failures
Last modified: 2013-09-29 22:08:11 EDT
Created attachment 343828 [details]
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 1 FAIL : Test: 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,
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.
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 220.127.116.11-117.fc10.x86_64 #1 SMP Tue
Nov 18 11:58:53 EST 2008 x86_64 x86_64 x86_64 GNU/Linux
# rpm -q glibc
Version-Release number of selected component (if applicable):
# rpm -q glibc
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
Test: xfr=640 != 2048, zero read.
Expected 0 exit status - failed.
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.
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
You can download this test kernel from http://people.redhat.com/dzickus/el5
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described in this bug report. This report is therefore being
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