Re: [PATCH] tpm: Fix memory leak in tpmm_chip_alloc

From: Jarkko Sakkinen
Date: Mon Mar 07 2022 - 08:46:30 EST


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@xxxxxxxxxx>
> ---
> 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
> --- a/drivers/char/tpm/tpm-chip.c
> +++ 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)
> return ERR_PTR(rc);
>
> --
> 2.17.1
>

Please test against the latest in

git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git

and share your results.

BR, Jarkko