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Date:   Thu, 6 Sep 2018 14:00:16 +0100
From:   Wei Liu <wei.liu2@citrix.com>
To:     Vitaly Kuznetsov <vkuznets@redhat.com>
CC:     <xen-devel@lists.xenproject.org>, <linux-kernel@vger.kernel.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>, Wei Liu <wei.liu2@citrix.com>
Subject: Re: [PATCH] xen/manage: don't complain about an empty value in
 control/sysrq node
Message-ID: <20180906130016.3nu6zvitjci7x5ge@zion.uk.xensource.com>
References: <20180906112608.4221-1-vkuznets@redhat.com>
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On Thu, Sep 06, 2018 at 01:26:08PM +0200, Vitaly Kuznetsov wrote:
> When guest receives a sysrq request from the host it acknowledges it by
> writing '\0' to control/sysrq xenstore node. This, however, make xenstore
> watch fire again but xenbus_scanf() fails to parse empty value with "%c"
> format string:
> 
>  sysrq: SysRq : Emergency Sync
>  Emergency Sync complete
>  xen:manage: Error -34 reading sysrq code in control/sysrq
> 
> Ignore -ERANGE the same way we already ignore -ENOENT, empty value in
> control/sysrq is totally legal.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Reviewed-by: Wei Liu <wei.liu2@citrix.com>