linux-kernel - Re: [PATCH v2] i2c: fix reference leak in MP2 PCI device

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Message-ID: <eibktb7odiqdmcyv5cumc7h74ajjyv6ojn3felasxzcl2d7w2u@5nz7ybmldf35>
Date: Thu, 2 Oct 2025 02:04:41 +0200
From: Andi Shyti <andi.shyti@...nel.org>
To: Ma Ke <make24@...as.ac.cn>
Cc: syniurge@...il.com, shyam-sundar.s-k@....com, wsa@...nel.org, 
	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org, akpm@...ux-foundation.org, 
	stable@...r.kernel.org
Subject: Re: [PATCH v2] i2c: fix reference leak in MP2 PCI device

Hi again,

On Thu, Oct 02, 2025 at 01:56:30AM +0200, Andi Shyti wrote:
> Hi,
> 
> > diff --git a/drivers/i2c/busses/i2c-amd-mp2-pci.c b/drivers/i2c/busses/i2c-amd-mp2-pci.c
> > index ef7370d3dbea..60edbabc2986 100644
> > --- a/drivers/i2c/busses/i2c-amd-mp2-pci.c
> > +++ b/drivers/i2c/busses/i2c-amd-mp2-pci.c
> > @@ -458,13 +458,16 @@ struct amd_mp2_dev *amd_mp2_find_device(void)
> >  {
> >  	struct device *dev;
> >  	struct pci_dev *pci_dev;
> > +	struct amd_mp2_dev *mp2_dev;
> >  
> >  	dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL);
> >  	if (!dev)
> >  		return NULL;
> >  
> >  	pci_dev = to_pci_dev(dev);
> > -	return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
> > +	mp2_dev = (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
> > +	put_device(dev);
> > +	return mp2_dev;
> 
> the patch is good, but I don't think you need to declare mp2_dev
> because to_pci_dev(dev) should work even without hodling the
> reference of dev.
> 
> I also have to agree with Markus that something like:
> 
> struct device *dev __free(put_device) = ...; /* it can also be NULL */

sorry, please ignore this last comment, because if !dev we
shouldn't call put_device().

Andi