On Thursday 24 July 2008 22:50, Herbert Xu wrote:

On Thu, Jul 24, 2008 at 03:40:40PM +0300, Pekka Enberg wrote:

quoted

Using ksize() for skbs will crash your kernel for some configurations
because calling that function for memory allocated with
kmem_cache_alloc() is not supported by all the allocators (well,
SLOB).

So how about fixing the interface so that it can return an error
to indicate that the allocator doesn't support it? You're taking
away an entire interface just because an underlying implementation
that's used by a very small proportion of users doesn't do the
right thing.

You could easily add some function which returns a constant error for
SLOB and ksize for others, because slob typically contains very little
slack space (unless explicit alignment is asked for).

OTOH, skb allocation uses kmalloc don't they? So you could still use
SLOB ksize for that I guess.