linux-kernel - Re: [PATCH] vhost: zero vhost

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Message-ID: <CAGF4SLiKv06rzuGprfpWg-EOi8y+DW+cTybCkoT_9OoE+y8tcQ@mail.gmail.com>
Date:   Wed, 27 Mar 2019 13:08:53 -0400
From:   Vitaly Mayatskih <v.mayatskih@...il.com>
To:     Stefan Hajnoczi <stefanha@...hat.com>
Cc:     Michal Hocko <mhocko@...e.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] vhost: zero vhost_vsock memory on allocation

On Wed, Mar 27, 2019 at 12:49 PM Stefan Hajnoczi <stefanha@...hat.com> wrote:

> Which field was accessed before initialization?
>
> I ask because the situation is now unclear since code remains that
> assumes vsock is *not* zero-initialized:
>
>   vsock->guest_cid = 0; /* no CID assigned yet */
>
>   atomic_set(&vsock->queued_replies, 0);

It was hash.

> If we're going to zalloc, let's get rid of explicit zero
> initializations.  Or let's use kvmalloc() and fix the uninitialized
> access.  Mixing both is confusing.

I would go with zalloc, since it's easier to read and it prevents
further situations like this.
A zalloc was there originally (not in fallback though).