[RFT] sky2 vs iptables

[RFT] sky2 vs iptables

[Daniel Drake]

Hi,

There's a strange sky2 bug on the Gentoo bugzilla:
http://bugs.gentoo.org/show_bug.cgi?id=136508

sky2 seems to work OK, but breaks as soon as the iptables ruleset is 
loaded. Nothing can be pinged, etc.

Can someone try and reproduce this? The iptables rule script has been 
uploaded here:
http://bugs.gentoo.org/attachment.cgi?id=95694&action=view

The very last command in that file is the one which produces an error 
and stops everything working:

	iptables: Unknown error 18446744073709551615

Apparently a sky2 null deref has also been seen at this point, although 
I don't have further details on that.

Thanks!
Daniel

Re: [RFT] sky2 vs iptables

[Stephen Hemminger]

On Tue, 05 Sep 2006 21:36:24 -0400
Daniel Drake <dsd@gentoo.org> wrote:

> Hi,
> 
> There's a strange sky2 bug on the Gentoo bugzilla:
> http://bugs.gentoo.org/show_bug.cgi?id=136508
> 
> sky2 seems to work OK, but breaks as soon as the iptables ruleset is 
> loaded. Nothing can be pinged, etc.
> 
> Can someone try and reproduce this? The iptables rule script has been 
> uploaded here:
> http://bugs.gentoo.org/attachment.cgi?id=95694&action=view
> 
> The very last command in that file is the one which produces an error 
> and stops everything working:
> 
> 	iptables: Unknown error 18446744073709551615
> 
> Apparently a sky2 null deref has also been seen at this point, although 
> I don't have further details on that.
> 
> Thanks!
> Daniel
> -
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It might be an artifact of the way sky2 was allocating receive buffers.
Bridge-netfilter was assuming header space in the buffer, and would corrupt
other memory, maybe iptables is assuming as well. This makes sky2
use dev_alloc_skb that reserves space.
-----------------------
Subject: sky2: use dev_alloc_skb for receive buffers

Several code paths assume an additional 16 bytes of header padding
on the receive path. Use dev_alloc_skb to get that padding.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>

--- linux-2.6.17.11.orig/drivers/net/sky2.c
+++ linux-2.6.17.11/drivers/net/sky2.c
@@ -949,14 +949,14 @@ static void sky2_vlan_rx_kill_vid(struct
 /*
  * It appears the hardware has a bug in the FIFO logic that
  * cause it to hang if the FIFO gets overrun and the receive buffer
- * is not aligned. ALso alloc_skb() won't align properly if slab
+ * is not aligned. Also dev_alloc_skb() won't align properly if slab
  * debugging is enabled.
  */
 static inline struct sk_buff *sky2_alloc_skb(unsigned int size, gfp_t gfp_mask)
 {
 	struct sk_buff *skb;
 
-	skb = alloc_skb(size + RX_SKB_ALIGN, gfp_mask);
+	skb = __dev_alloc_skb(size + RX_SKB_ALIGN, gfp_mask);
 	if (likely(skb)) {
 		unsigned long p	= (unsigned long) skb->data;
 		skb_reserve(skb, ALIGN(p, RX_SKB_ALIGN) - p);
@@ -1855,7 +1855,7 @@ static struct sk_buff *sky2_receive(stru
 		goto oversize;
 
 	if (length < copybreak) {
-		skb = alloc_skb(length + 2, GFP_ATOMIC);
+		skb = dev_alloc_skb(length + 2);
 		if (!skb)
 			goto resubmit;
 

Re: [RFT] sky2 vs iptables

[Daniel Drake]

Stephen Hemminger wrote:
> On Tue, 05 Sep 2006 21:36:24 -0400
> Daniel Drake <dsd@gentoo.org> wrote:
>> There's a strange sky2 bug on the Gentoo bugzilla:
>> http://bugs.gentoo.org/show_bug.cgi?id=136508
>>
>> sky2 seems to work OK, but breaks as soon as the iptables ruleset is 
>> loaded. Nothing can be pinged, etc.
>>
>> Can someone try and reproduce this? The iptables rule script has been 
>> uploaded here:
>> http://bugs.gentoo.org/attachment.cgi?id=95694&action=view
>>
>> The very last command in that file is the one which produces an error 
>> and stops everything working:
>>
>> 	iptables: Unknown error 18446744073709551615
>>
>> Apparently a sky2 null deref has also been seen at this point, although 
>> I don't have further details on that.
> 
> It might be an artifact of the way sky2 was allocating receive buffers.
> Bridge-netfilter was assuming header space in the buffer, and would corrupt
> other memory, maybe iptables is assuming as well. This makes sky2
> use dev_alloc_skb that reserves space.
> -----------------------
> Subject: sky2: use dev_alloc_skb for receive buffers

Unfortunately the problem still exists with this patch. Any other ideas?

Daniel

Re: [RFT] sky2 vs iptables

[Stephen Hemminger]

On Sat, 16 Sep 2006 23:01:46 -0400
Daniel Drake <dsd@gentoo.org> wrote:

> Stephen Hemminger wrote:
> > On Tue, 05 Sep 2006 21:36:24 -0400
> > Daniel Drake <dsd@gentoo.org> wrote:
> >> There's a strange sky2 bug on the Gentoo bugzilla:
> >> http://bugs.gentoo.org/show_bug.cgi?id=136508
> >>
> >> sky2 seems to work OK, but breaks as soon as the iptables ruleset is 
> >> loaded. Nothing can be pinged, etc.
> >>
> >> Can someone try and reproduce this? The iptables rule script has been 
> >> uploaded here:
> >> http://bugs.gentoo.org/attachment.cgi?id=95694&action=view
> >>
> >> The very last command in that file is the one which produces an error 
> >> and stops everything working:
> >>
> >> 	iptables: Unknown error 18446744073709551615
> >>
> >> Apparently a sky2 null deref has also been seen at this point, although 
> >> I don't have further details on that.
> > 
> > It might be an artifact of the way sky2 was allocating receive buffers.
> > Bridge-netfilter was assuming header space in the buffer, and would corrupt
> > other memory, maybe iptables is assuming as well. This makes sky2
> > use dev_alloc_skb that reserves space.
> > -----------------------
> > Subject: sky2: use dev_alloc_skb for receive buffers
> 
> Unfortunately the problem still exists with this patch. Any other ideas?
> 
> Daniel

I tried the script with 2.6.18 and saw no problem.
Of course, my configuration was probably different and I wasn't
running Gentoo.   Eth0 was a sky2 device, and eth1 was a skge.

Re: [RFT] sky2 vs iptables

[Daniel Drake]

Stephen Hemminger wrote:
> I tried the script with 2.6.18 and saw no problem.
> Of course, my configuration was probably different and I wasn't
> running Gentoo.   Eth0 was a sky2 device, and eth1 was a skge.
> 

This turned out to be a netfilter configuration issue. sky2+iptables 
works fine when the kernel is compiled correctly. Sorry for the noise, 
although the netfilter error messages weren't exactly clear that certain 
modules were missing!

Daniel