linux-kernel - Re: [PATCH v4 18/29] i2c: mux: Create missing devlink between mux and adapter physical device

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Message-ID: <aQOkUa1IwuiOeSvT@smile.fi.intel.com>
Date: Thu, 30 Oct 2025 19:45:53 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Andi Shyti <andi.shyti@...nel.org>
Cc: Herve Codina <herve.codina@...tlin.com>, Andrew Lunn <andrew@...n.ch>,
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Subject: Re: [PATCH v4 18/29] i2c: mux: Create missing devlink between mux
 and adapter physical device

On Thu, Oct 30, 2025 at 04:23:24PM +0100, Andi Shyti wrote:

...

> > +	dl = device_link_add(muxc->dev, parent_physdev, DL_FLAG_AUTOREMOVE_CONSUMER);
> 
> Not to call twice put_device, I would add it once here and then
> check for !dl.

I was almost commenting the same in one of the previous rounds, but...

> > +	if (!dl) {
> > +		dev_err(muxc->dev, "failed to create device link to %s\n",
> > +			dev_name(parent_physdev));

...haven't you noticed this use? With your (and my old) suggestion this may
lead to NULL / stale pointer dereference.

> > +		put_device(parent_physdev);
> > +		ret = -EINVAL;
> > +		goto err_free_priv;
> > +	}
> > +	put_device(parent_physdev);

-- 
With Best Regards,
Andy Shevchenko