Re: [Xen-devel] [PATCH]Fix memory leak for copy-receiver of netfront

[Kasai Takanori <kasai.takanori@xxxxxxxxxxxxxx>]

Hi Jeremy,

I reviewed the 2.6.25 versions of netfront.

First of all, the xennet_release_rx_bufs() function is freeing 
processing of flipping mode. 
Therefore, more memory leaks are generated. 

It is necessary to change to the freeing processing of the copy-receiver 
mode referring to the following patch. 
http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/41918416db51

And, if this patch that we made is applied, the memory leak will not be 
generated. 

Best Regards,

---
Takanori Kasai

---------- Original Message ----------
>Date:     2008/06/12
>From:     Jeremy Fitzhardinge <jeremy@xxxxxxxx>
>To:       Kasai Takanori <kasai.takanori@xxxxxxxxxxxxxx>
>Cc:       xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
>Subject:  Re: [Xen-devel] [PATCH]Fix memory leak for copy-receiver of 
>          netfront
>
>Kasai Takanori wrote:
>> Hi all,
>>
>> We found the problem of the memory leak when working with copy-
>> receiver of netfront.
>>
>> The source of a problem is that the fragment page is not released with 
>> dev_kfree_skb() because the nr_frags variable of skb is set to 0. 
>>
>> This is the patch to fix memory leak in netfront.
>>   
>
>This code doesn't apply to the current 2.6.25 version of netfront.  The 
>only similar code I could see is:
>
>                skb = np->rx_skbs[id];
>                mfn = gnttab_end_foreign_transfer_ref(ref);
>                gnttab_release_grant_reference(&np->gref_rx_head, ref);
>                np->grant_rx_ref[id] = GRANT_INVALID_REF;
>
>                if (0 == mfn) {
>                        skb_shinfo(skb)->nr_frags = 0;
>                        dev_kfree_skb(skb);
>                        noxfer++;
>                        continue;
>                }
>
>
>Would you mind reviewing the 2.6.25 version of netfront to see if it 
>needs a patch?
>
>Thanks,
>    J
>
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