Date: Fri, 13 May 2011 19:17:54 GMT From: Aragon Gouveia <aragon@phat.za.net> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/157013: Bizarre file descriptor race condition Message-ID: <201105131917.p4DJHsWV027213@red.freebsd.org> Resent-Message-ID: <201105131920.p4DJKALe038231@freefall.freebsd.org>
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>Number: 157013
>Category: misc
>Synopsis: Bizarre file descriptor race condition
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri May 13 19:20:10 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator: Aragon Gouveia
>Release: 8.2-STABLE
>Organization:
>Environment:
FreeBSD igor.geek.sh 8.2-STABLE FreeBSD 8.2-STABLE #2: Thu May 5 14:52:46 SAST 2011 toor@igor.geek.sh:/usr/obj/usr/src-RELENG_8/sys/IGOR amd64
>Description:
Please see the script pasted in the repeat field.
When it is run, the while loop exits after the first iteration. However, if the ssh command is commented, the loop executes two iterations.
Stranger still, on some of my FreeBSD systems the script works correctly _sometimes_, but mostly not.
>How-To-Repeat:
#!/bin/sh
DFRTMP=$(mktemp -d /tmp/dfr.XXXXXX)
[ $? -eq 0 ] || exit 1
cat >${DFRTMP}/hosts <<"_EOF"
1 saturn.geek.sh
2 null
_EOF
while read hostid hostname; do
echo ${hostid}:${hostname}
ssh ${hostname} 'df -k'
done <${DFRTMP}/hosts
rm -rf ${DFRTMP}
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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