linux-kernel - Re: [PATCH] tpm: Fix memory leak in tpmm_chip

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Message-ID: <YjLjvqWdhy6REIrn@iki.fi>
Date:   Thu, 17 Mar 2022 09:31:10 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Jason Gunthorpe <jgg@...pe.ca>
Cc:     GUO Zihua <guozihua@...wei.com>, linux-integrity@...r.kernel.org,
        wangweiyang2@...wei.com, xiujianfeng@...wei.com,
        weiyongjun1@...wei.com, peterhuewe@....de,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tpm: Fix memory leak in tpmm_chip_alloc

On Mon, Mar 14, 2022 at 01:37:05PM -0300, Jason Gunthorpe wrote:
> On Mon, Mar 07, 2022 at 06:48:27PM +0800, GUO Zihua wrote:
> > Fix a memory leak in tpmm_chip_alloc. devm_add_action_or_reset would
> > call put_device on error, while tpm->devs is left untouched. Call
> > put_device on tpm->devs as well if devm_add_action_or_reset returns an
> > error.
> > 
> > Fixes: fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm")
> > Signed-off-by: GUO Zihua <guozihua@...wei.com>
> >  drivers/char/tpm/tpm-chip.c | 13 +++++++++----
> >  1 file changed, 9 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> > index b009e7479b70..0a92334e8c40 100644
> > +++ b/drivers/char/tpm/tpm-chip.c
> > @@ -308,6 +308,12 @@ static int tpm_class_shutdown(struct device *dev)
> >  	return 0;
> >  }
> >  
> > +static void tpm_chip_free(struct tpm_chip *chip)
> > +{
> > +	put_device(&chip->devs);
> > +	put_device(&chip->dev);
> > +}
> > +
> >  /**
> >   * tpm_chip_alloc() - allocate a new struct tpm_chip instance
> >   * @pdev: device to which the chip is associated
> > @@ -396,8 +402,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
> >  	return chip;
> >  
> >  out:
> > -	put_device(&chip->devs);
> > -	put_device(&chip->dev);
> > +	tpm_chip_free(chip);
> >  	return ERR_PTR(rc);
> >  }
> >  EXPORT_SYMBOL_GPL(tpm_chip_alloc);
> > @@ -420,8 +425,8 @@ struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
> >  		return chip;
> >  
> >  	rc = devm_add_action_or_reset(pdev,
> > -				      (void (*)(void *)) put_device,
> > -				      &chip->dev);
> > +				      (void (*)(void *)) tpm_chip_free,
> > +				      chip);
> >  	if (rc)
> 
> This looks like the same issue as was adressed by the recent discussion..

Both fixes (Lino, jejb) are also part of my PR:

[*] https://lore.kernel.org/linux-integrity/Yi64TJXqto+VdoOo@iki.fi/

> Jason

BR, Jarkko