linux-kernel - Re: [PATCH 1/4] tpm: in case of error properly cleanup in tpmm_chip

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Message-ID: <YAR9FGbjAArQ0nw3@kernel.org>
Date:   Sun, 17 Jan 2021 20:08:20 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Lino Sanfilippo <LinoSanfilippo@....de>
Cc:     peterhuewe@....de, jgg@...pe.ca, stefanb@...ux.vnet.ibm.com,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        p.rosenberger@...bus.com, Lino Sanfilippo <l.sanfilippo@...bus.com>
Subject: Re: [PATCH 1/4] tpm: in case of error properly cleanup in
 tpmm_chip_alloc

On Sat, Jan 16, 2021 at 02:22:38AM +0100, Lino Sanfilippo wrote:
> From: Lino Sanfilippo <l.sanfilippo@...bus.com>
> 
> In tpmm_chip_alloc() a resource management action handler is installed to
> release the chip->dev in case of error. This will result in the chip being
> freed if it was the last reference. If the installation of the handler was
> not successful an error is returned to the caller.
> However in this case the chip->dev reference is not put and thus the chip
> is never freed. Fix this by releasing the reference "by hand" in case that
> the action handler installation failed.
> 
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
> ---
>  drivers/char/tpm/tpm-chip.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index ddaeceb..e242d2e 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -423,11 +423,15 @@ struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
>  				      (void (*)(void *)) put_device,
>  				      &chip->dev);
>  	if (rc)
> -		return ERR_PTR(rc);
> +		goto put_dev;
>  
>  	dev_set_drvdata(pdev, chip);
>  
>  	return chip;
> +
> +put_dev:
> +	put_device(&chip->dev);
> +	return ERR_PTR(rc);
>  }
>  EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
>  
> -- 
> 2.7.4
> 

NAK

[*] https://elixir.bootlin.com/linux/v5.11-rc3/source/include/linux/device.h#L257

/Jarkko