linux-kernel - Re: [PATCH v8 4/8] i2c: Introduce OF component probe function

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Zw-VkQ3di5nFHiXB@smile.fi.intel.com>
Date: Wed, 16 Oct 2024 13:29:37 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Chen-Yu Tsai <wenst@...omium.org>
Cc: Doug Anderson <dianders@...omium.org>, Rob Herring <robh@...nel.org>,
	Saravana Kannan <saravanak@...gle.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Wolfram Sang <wsa@...nel.org>, Benson Leung <bleung@...omium.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>, chrome-platform@...ts.linux.dev,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Johan Hovold <johan@...nel.org>, Jiri Kosina <jikos@...nel.org>,
	linux-i2c@...r.kernel.org
Subject: Re: [PATCH v8 4/8] i2c: Introduce OF component probe function

On Wed, Oct 16, 2024 at 05:28:05PM +0800, Chen-Yu Tsai wrote:
> On Wed, Oct 16, 2024 at 3:01 PM Chen-Yu Tsai <wenst@...omium.org> wrote:
> > On Wed, Oct 16, 2024 at 1:58 AM Doug Anderson <dianders@...omium.org> wrote:
> > > On Tue, Oct 8, 2024 at 12:35 AM Chen-Yu Tsai <wenst@...omium.org> wrote:

...

> > > ...which means it'll call of_node_put() to free "i2c_node" when it
> > > goes out of scope. of_node_put() handles NULL pointers but _not_ ERR
> > > pointers. So I think that if you get an error back and then return via
> > > the PTR_ERR(i2c_node) then it'll crash because it will try to free an
> > > ERR pointer. Did I get that right? Presumably you need to instead do:
> > >
> > >   return PTR_ERR(no_free_ptr(i2c_node));
> > >
> > > ...or change of_node_put() to be a noop for error pointers?
> >
> > Good catch! As Andy suggested, it should be updated to handle both.
> > I'll add a patch for this.
> 
> On second thought, it might be better to change i2c_of_probe_get_i2c_node()
> to return NULL on errors. That seems to be what most functions do. I only
> found a handful of exceptions.

It seems that OF has been written in the assumption that device node pointer
is never an error pointer. So, probably fixing your function is the best
approach right now.

-- 
With Best Regards,
Andy Shevchenko