Re: Nasal demons in preprocessor use (Re: [PATCH] test-suite: new preprocessor test case)

[Al Viro <viro@ZenIV.linux.org.uk>]

On Thu, Mar 19, 2009 at 08:27:58PM +0100, Ingo Molnar wrote:
> Vegard, it's this bit:
> 
>         kmemcheck_define_bitfield(flags2, {
> #ifdef CONFIG_IPV6_NDISC_NODETYPE
>                 __u8                    ndisc_nodetype:2;
> #endif
> #if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE)
>                 __u8                    do_not_encrypt:1;
>                 __u8                    requeue:1;
> #endif
>         });

BTW, there's a related turd: kernel/cred.c
        if (
#ifdef CONFIG_KEYS
                !p->cred->thread_keyring &&
#endif
                clone_flags & CLONE_THREAD
            ) {
is not only ucking fugly, it's not a valid C if you have PROFILE_ALL_BRANCHES
set.  Why?  Because then we get if() #defined ;-/

BTW^2, speaking of that ifdef...  What happens to
static void put_cred_rcu(struct rcu_head *rcu)
{
        struct cred *cred = container_of(rcu, struct cred, rcu);

        if (atomic_read(&cred->usage) != 0)
                panic("CRED: put_cred_rcu() sees %p with usage %d\n",
                      cred, atomic_read(&cred->usage));

        security_cred_free(cred);
        key_put(cred->thread_keyring);
        key_put(cred->request_key_auth);
        release_tgcred(cred);
        put_group_info(cred->group_info);
        free_uid(cred->user);
        kmem_cache_free(cred_jar, cred);
}
if CONFIG_KEYS is not set?