Subject: Re: [PATCH] net: Add back alignment for size for __alloc_skb

From: Eric Dumazet <[email-masked]>
Date: Thu, 03 Nov 2011 00:14:12 +0100

On 03/11/2011 00:09, David Miller wrote:

> From: Eric Dumazet <[email-masked]>
> Date: Wed, 02 Nov 2011 23:55:11 +0100
> 
>> There is a problem with your kmalloc() or alignments on your architecture.
>>
>> What is the SMP_CACHE_BYTES value ?
> 
> kmalloc() behavior doesn't have anything to do with this bug.
> 
> The issue is calculation of skb->end, which is based upon calculated
> 'size' variable.
> 
> skb->end determines alignment of skb_shared_info, which is where the
> alignment problem is occuring for Tony.
> 

I understood that David, but check the code, and you can see that exact
skb->end depends also on ksize()

So maybe the right fix is to make sure skb->end is properly aligned, say
with SLOB

So a more generic fix is welcomed.