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

[Guozihua (Scott)]

On 2022/3/12 0:34, Jarkko Sakkinen wrote:
> On Thu, 2022-03-10 at 11:33 +0800, Guozihua (Scott) wrote:
> > On 2022/3/7 21:45, Jarkko Sakkinen 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@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
> > > .
> >
> > Hi Jarkko,
> >
> > I'll do that. Do we have a test set for TPM? Or do we just build and run
> > it and see if everything works as expected?
> >
> > This is an error handling optimization BTW.
>
> There is kselftest in tools/testing/kselftes/tpm2 that you can use
> but do not have to.
>
> BR, Jarkko

Great! Thanks Jarkko!

--
Best
GUO Zihua