Linux kernel NULL-pointer dereference in memset from kzalloc

Quite by chance stumbled upon some code in kernel jungles and was a bit confused. There are two implementations of kzalloc(): in tools/virtio/linux/kernel.h and the main one in linux/slab.h. Obviously, in most cases the second one is used. But sometimes the "virtio"kzalloc() is used.

"virtio"kzalloc() looks like this:

static inline void *kzalloc(size_t s, gfp_t gfp)
{
    void *p = kmalloc(s, gfp);

    memset(p, 0, s);
    return p;
}

My confusion is that "fake"kmalloc() used inside "tools" directory can return NULL-pointer. Also it looks like the memset() implementation doesn't check NULL-pointers so there could be NULL-pointer dereference. Is it a bug or am I missing something?