From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olaf Hering <olaf@aepfle.de>
Subject: Re: [PATCH] hotplug/Linux: close lockfd after lock
 attempt
Date: Sun, 14 Oct 2012 00:35:58 +0200
Message-ID: <20121013223558.GA19665@aepfle.de>
References: <5aa14d5afe6b1f35b230.1350143968@probook.site>
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On Sat, Oct 13, Olaf Hering wrote:

> hotplug/Linux: close lockfd after lock attempt
> 
> When a HVM guest is shutdown some of the 'remove' events can not claim
> the lock for some reason. Instead they try to grab the lock in a busy
> loop, until udev reaps the xen-hotplug-cleanup helper.
> After analyzing the resulting logfile its not obvious what the cause is.
> The only explanation is that bash (?) gets confused if the same lockfd
> is opened again and again. Closing it in each iteration seem to fix the
> issue.

Can be reproduced with this testcase on sles11sp2, not on openSuSE 11.4:

 # cat test.sh
set -x
source locking.sh

l=lock
claim_lock $l
sleep 1
release_lock $l


 # bash test.sh & bash test.sh & bash test.sh & bash test.sh &


Olaf