Messages in this thread Patch in this message | | | Date | Wed, 20 Dec 2017 11:08:55 -0700 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 1/4] tpm: fix access attempt to an already unmapped I/O memory region |
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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@redhat.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 > +++ b/drivers/char/tpm/tpm_tis_core.c
Yoiks. This patch is helping but the more I look at this the wronger everything looks..
1) tpm_chip_unregister makes chip->ops == NULL, so this sequence:
static int tpm_tis_plat_remove(struct platform_device *pdev) tpm_chip_unregister(chip); tpm_tis_remove(chip); void tpm_tis_remove(struct tpm_chip *chip) if (chip->ops->clk_enable != NULL)
Will oops
2) tpm_chip_register can also NULL ops in error cases, so this sequence can oops:
rc = tpm_chip_register(chip); if (rc && is_bsw()) iounmap(priv->ilb_base_addr);
if (chip->ops->clk_enable != NULL) chip->ops->clk_enable(chip, false);
3) iounmap should not be split between tpm_tis and tpm_tis_core Put it at the end of tpm_tis_remove.
4) This sequence:
+ return tpm_chip_register(chip); +out_err: + tpm_tis_remove(chip); + return rc;
Doesn't look right. If tpm_chip_register fails then tpm_tis_remove will never be called. This was sort of OK when tpm_tis_remove didn't manage any resources, but now that it does the above needs fixing too.
The below draft fixes everything except #1. That needs a more thoughtful idea..
Jason
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c index d29add49b03388..09f18e2e644774 100644 --- a/drivers/char/tpm/tpm_tis.c +++ b/drivers/char/tpm/tpm_tis.c @@ -275,9 +275,6 @@ static void tpm_tis_pnp_remove(struct pnp_dev *dev) tpm_chip_unregister(chip); tpm_tis_remove(chip); - if (is_bsw()) - iounmap(priv->ilb_base_addr); - } static struct pnp_driver tis_pnp_driver = { @@ -328,10 +325,6 @@ static int tpm_tis_plat_remove(struct platform_device *pdev) tpm_chip_unregister(chip); tpm_tis_remove(chip); - - if (is_bsw()) - iounmap(priv->ilb_base_addr); - return 0; } diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index c2227983ed88d4..ffda1694a6aba3 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -727,6 +727,9 @@ void tpm_tis_remove(struct tpm_chip *chip) if (chip->ops->clk_enable != NULL) chip->ops->clk_enable(chip, false); + + if (priv->ilb_base_addr) + iounmap(priv->ilb_base_addr); } EXPORT_SYMBOL_GPL(tpm_tis_remove); @@ -921,22 +924,15 @@ 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); - if (chip->ops->clk_enable != NULL) chip->ops->clk_enable(chip, false); - return rc; + rc = tpm_chip_register(chip); + if (rc): + goto out_err; + return 0; 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); - return rc; } EXPORT_SYMBOL_GPL(tpm_tis_core_init);
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