Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20190307093408.3425010-1-arnd@arndb.de> <20190307100605.GA20309@unicorn.suse.cz>
In-Reply-To: <20190307100605.GA20309@unicorn.suse.cz>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 7 Mar 2019 16:59:19 +0100
Message-ID: <CAK8P3a3YLD2K-bGXCiN4xQNQhGCLzVE4C9WonFGTo7LN30v4pg@mail.gmail.com>
Subject: Re: [PATCH] ethtool: reduce stack usage with clang
To:     Michal Kubecek <mkubecek@suse.cz>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Jiri Pirko <jiri@mellanox.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Kees Cook <keescook@chromium.org>,
        Wenwen Wang <wang6495@umn.edu>,
        Ilya Lesokhin <ilyal@mellanox.com>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Edward Cree <ecree@solarflare.com>,
        Networking <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Mar 7, 2019 at 11:06 AM Michal Kubecek <mkubecek@suse.cz> wrote:
>
> On Thu, Mar 07, 2019 at 10:33:35AM +0100, Arnd Bergmann wrote:

> > @@ -2533,7 +2535,7 @@ static int ethtool_set_fecparam(struct net_device *dev, void __user *useraddr)
> >
> >  /* The main entry point in this file.  Called from net/core/dev_ioctl.c */
> >
> > -int dev_ethtool(struct net *net, struct ifreq *ifr)
> > +int noinline_for_stack dev_ethtool(struct net *net, struct ifreq *ifr)
> >  {
> >       struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
> >       void __user *useraddr = ifr->ifr_data;
>
> Is this part really needed? AFAICS dev_ethtool() is only called from
> dev_ioctl() which is in a different compilation unit so that
> dev_ethtool() won't be inlined anyway.

No, you are right. I had accidentally left this in place from an earlier
version. Sending a v2 now.

      Arnd