[PATCH] random: Fix crashes with sparse node ids

Linus Torvalds torvalds at linux-foundation.org
Sun Jul 31 06:27:00 AEST 2016

On Sat, Jul 30, 2016 at 7:23 AM, Michael Ellerman <mpe at ellerman.id.au> wrote:
>  #ifdef CONFIG_NUMA
> -       pool = kmalloc(num_nodes * sizeof(void *),
> +       pool = kmalloc(nr_node_ids * sizeof(void *),
>                        GFP_KERNEL|__GFP_NOFAIL|__GFP_ZERO);
>         for_each_online_node(i) {
>                 crng = kmalloc_node(sizeof(struct crng_state),

Ugh. Can we please also just change that kmalloc to kcalloc()? Get rid
of the odd multiplication and the unusual GFP mask bit crud?

And instead of using "sizeof(void *)", just use the pool entry size,
ie "sizeof(*pool)". Yes, we have other places where we depend on void
pointers having the same size as others, but it's the RightThing(tm)
to do anyway, and it makes more sense when you grep things ("Oh, we're
allocating 'nr_node_id' copes of *pool entries" even without knowing
what type is behind the "pool" pointer).

IOW, can you confirm that you could just use

        pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL);

instead? I'd much rather apply that patch.


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