netdev - Re: [PATCH] net/core/neighbour: tell kmemleak about hash tables

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Date:   Fri, 11 Jan 2019 07:26:09 +0300
From:   Konstantin Khlebnikov <koct9i@...il.com>
To:     Cong Wang <xiyou.wangcong@...il.com>
Cc:     Konstantin Khlebnikov <khlebnikov@...dex-team.ru>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Catalin Marinas <catalin.marinas@....com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] net/core/neighbour: tell kmemleak about hash tables

On Thu, Jan 10, 2019 at 11:45 PM Cong Wang <xiyou.wangcong@...il.com> wrote:
>
> On Tue, Jan 8, 2019 at 1:30 AM Konstantin Khlebnikov
> <khlebnikov@...dex-team.ru> wrote:
> > @@ -443,12 +444,14 @@ static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
> >         ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
> >         if (!ret)
> >                 return NULL;
> > -       if (size <= PAGE_SIZE)
> > +       if (size <= PAGE_SIZE) {
> >                 buckets = kzalloc(size, GFP_ATOMIC);
> > -       else
> > +       } else {
> >                 buckets = (struct neighbour __rcu **)
> >                           __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
> >                                            get_order(size));
> > +               kmemleak_alloc(buckets, size, 0, GFP_ATOMIC);
>
> Why min_count is 0 rather than 1 here?

The api isn't clear and I've misread description.
So it should be 1 for reporting leak of hash table itself.
But 0 doesn't add any new issues.