On Thu, 3 Dec 2020 at 19:01, Eric Dumazet <[email protected]> wrote: > On 12/3/20 6:41 PM, Marco Elver wrote: > > > One more experiment -- simply adding > > > > --- a/net/core/skbuff.c > > +++ b/net/core/skbuff.c > > @@ -207,7 +207,21 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t > > gfp_mask, > > */ > > size = SKB_DATA_ALIGN(size); > > size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); > > + size = 1 << kmalloc_index(size); /* HACK */ > > data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc); > > > > > > also got rid of the warnings. Something must be off with some value that > > is computed in terms of ksize(). If not, I don't have any explanation > > for why the above hides the problem. > > Maybe the implementations of various macros (SKB_DATA_ALIGN and friends) > hae some kind of assumptions, I will double check this.
If I force kfence to return 4K sized allocations for everything, the warnings remain. That might suggest that it's not due to a missed ALIGN. Is it possible that copies or moves are a problem? E.g. we copy something from kfence -> non-kfence object (or vice-versa), and ksize() no longer matches, then things go wrong? Thanks, -- Marco
