From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Chen, Tiejun" <tiejun.chen@intel.com>
Subject: Re: [v3][PATCH 13/16] tools/libxl: detect and avoid
 conflicts with RDM
Date: Tue, 16 Jun 2015 09:44:10 +0800
Message-ID: <557F7F6A.4030805@intel.com>
References: <1433985325-16676-1-git-send-email-tiejun.chen@intel.com>
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	<20150612163944.GZ14606@zion.uk.xensource.com>
	<557E2F79.7050502@intel.com>
	<20150615150107.GC10177@zion.uk.xensource.com>
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To: Wei Liu <wei.liu2@citrix.com>
Cc: kevin.tian@intel.com, ian.campbell@citrix.com, andrew.cooper3@citrix.com, tim@xen.org, xen-devel@lists.xen.org, stefano.stabellini@citrix.com, jbeulich@suse.com, yang.z.zhang@intel.com, Ian.Jackson@eu.citrix.com
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On 2015/6/15 23:01, Wei Liu wrote:
> On Mon, Jun 15, 2015 at 09:50:49AM +0800, Chen, Tiejun wrote:
> [...]
>>>> +                   uint32_t flag,
>>>> +                   uint16_t seg,
>>>> +                   uint8_t bus,
>>>> +                   uint8_t devfn,
>>>> +                   unsigned int *nr_entries)
>>>> +{
>>>> +    struct xen_reserved_device_memory *xrdm;
>>>> +    int rc;
>>>> +
>>>> +    rc = xc_reserved_device_memory_map(CTX->xch, flag, seg, bus, devfn,
>>>> +                                       NULL, nr_entries);
>>>
>>> xc_reserved_device_memory_map dereferences nr_entries. You need to make
>>> sure there is no garbage value in nr_entries. I.e. you need to
>>> initialise nr_entries to 0 before passing it in.
>>
>> Sure, so what about this?
>>
>> /*
>>   * We really can't presume how many entries we can get in advance.
>>   */
>> if (*nr_entries)
>>      *nr_entries = 0;
>>
>
> You might just unconditionally set *nr_entries to 0.
>

Okay.

Thanks
Tiejun