linux-kernel - Re: [PATCH 1/4] tpm: fix access attempt to an already unmapped I/O memory region

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Date:   Fri, 22 Dec 2017 20:35:06 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Javier Martinez Canillas <javierm@...hat.com>
Cc:     linux-kernel@...r.kernel.org, James Ettle <james@...le.org.uk>,
        Hans de Goede <hdegoede@...hat.com>,
        Azhar Shaikh <azhar.shaikh@...el.com>,
        Arnd Bergmann <arnd@...db.de>, Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-integrity@...r.kernel.org
Subject: Re: [PATCH 1/4] tpm: fix access attempt to an already unmapped I/O
 memory region

On Wed, Dec 20, 2017 at 12:35:35PM +0100, Javier Martinez Canillas wrote:
> The driver maps the I/O memory address to control the LPC bus CLKRUN_EN,
> but on the error path the memory is accessed by the .clk_enable handler
> after this was already unmapped. So only unmap the I/O memory region if
> it will not be used anymore.
> 
> Also, the correct thing to do is to cleanup the resources in the inverse
> order that were acquired to prevent issues like these.
> 
> Signed-off-by: Javier Martinez Canillas <javierm@...hat.com>
> ---
> 
>  drivers/char/tpm/tpm_tis_core.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index c2227983ed88..3455abbb2035 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -923,7 +923,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
>  
>  	rc = tpm_chip_register(chip);
>  	if (rc && is_bsw())
> -		iounmap(priv->ilb_base_addr);
> +		goto out_err;
>  
>  	if (chip->ops->clk_enable != NULL)
>  		chip->ops->clk_enable(chip, false);
> @@ -931,12 +931,13 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
>  	return rc;
>  out_err:
>  	tpm_tis_remove(chip);
> -	if (is_bsw())
> -		iounmap(priv->ilb_base_addr);
>  
>  	if (chip->ops->clk_enable != NULL)
>  		chip->ops->clk_enable(chip, false);
>  
> +	if (is_bsw())
> +		iounmap(priv->ilb_base_addr);
> +
>  	return rc;
>  }
>  EXPORT_SYMBOL_GPL(tpm_tis_core_init);
> -- 
> 2.14.3
> 

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>

/Jarkko