Re: [Xen-users] kernel 3.9.2 - xen 4.2.2/4.3rc1 => BUG unable to handle kernel paging request netif_poll+0x49c/0xe8

[Dion Kant <g.w.kant@hunenet.nl>]

On 07/05/2013 12:54 PM, Wei Liu wrote:
>>
>> [    7.670132] Adding 4192252k swap on /dev/xvda1.  Priority:-1
>> extents:1 across:4192252k SS
>> [   10.204340] NET: Registered protocol family 17
>> [  481.534979] netfront: Too many frags
>> [  487.543946] netfront: Too many frags
>> [  491.049458] netfront: Too many frags
>> [  491.491153] ------------[ cut here ]------------
>> [  491.491628] kernel BUG at drivers/xen/netfront/netfront.c:1295!
> 
> So what's the code around line 1295? There must be a BUG_ON there. It's
> normal you didn't see the same line number in my patch (1306) because we
> were using different kernel.
> 

Yes, stupid me. I was definitely in a wrong state when writing this.
Even more stupid, I did make the same stupid remark after obtaining
results with Jan's patch. 1000 times sorry... ( I was to much in a hurry
to get my response back to you likely because I was happy that you guys
could free some for this.)

So now we know that nr_frags >= MAX_SKB_FRAGS

1285 static RING_IDX xennet_fill_frags(struct netfront_info *np,
1286                                   struct sk_buff *skb,
1287                                   struct sk_buff_head *list)
1288 {
1289         struct skb_shared_info *shinfo = skb_shinfo(skb);
1290         int nr_frags = shinfo->nr_frags;
1291         RING_IDX cons = np->rx.rsp_cons;
1292         struct sk_buff *nskb;
1293
1294         while ((nskb = __skb_dequeue(list))) {
1295                BUG_ON(nr_frags >= MAX_SKB_FRAGS);
1296
1297                 struct netif_rx_response *rx =
1298                         RING_GET_RESPONSE(&np->rx, ++cons);
1299

>>
>> In the mean time Jan took the bug in bugzilla
>> (https://bugzilla.novell.com/show_bug.cgi?id=826374) and created a first
>> patch. I propose we continue the discussion there and post the
>> conclusion in this list to finish this thread here as well.
>>
> 
> I'm not so sure what's the best way. In general it would be much a
> burden for developers to look at every bugzilla, let alone register
> account for each bugzilla.
> 
> Anyway, as we already started the discussion here, I think we should
> just continue it here. We could do this the other way around, discuss
> here and post conclusion / references there.

This is oke with me. I was wondering what would be most convenient.

Dion