drivers: base: power: fix memory leak with using debugfs_lookup()

  When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at
once.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/base/power/domain.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
  

On Thu, Feb 2, 2023 at 3:15 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time.  To make things simpler, just
> call debugfs_lookup_and_remove() instead which handles all of the logic
> at
> once.
>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Kevin Hilman <khilman@kernel.org>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Len Brown <len.brown@intel.com>
> Cc: linux-pm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/base/power/domain.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 967bcf9d415e..6097644ebdc5 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -220,13 +220,10 @@ static void genpd_debug_add(struct generic_pm_domain *genpd);
>
>  static void genpd_debug_remove(struct generic_pm_domain *genpd)
>  {
> -       struct dentry *d;
> -
>         if (!genpd_debugfs_dir)
>                 return;
>
> -       d = debugfs_lookup(genpd->name, genpd_debugfs_dir);
> -       debugfs_remove(d);
> +       debugfs_lookup_and_remove(genpd->name, genpd_debugfs_dir);
>  }
>
>  static void genpd_update_accounting(struct generic_pm_domain *genpd)
> --

Does this depend on anything in your tree, or can I apply it?
  

On Thu, 2 Feb 2023 at 15:15, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time.  To make things simpler, just
> call debugfs_lookup_and_remove() instead which handles all of the logic
> at
> once.
>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Kevin Hilman <khilman@kernel.org>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Len Brown <len.brown@intel.com>
> Cc: linux-pm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe

> ---
>  drivers/base/power/domain.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 967bcf9d415e..6097644ebdc5 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -220,13 +220,10 @@ static void genpd_debug_add(struct generic_pm_domain *genpd);
>
>  static void genpd_debug_remove(struct generic_pm_domain *genpd)
>  {
> -       struct dentry *d;
> -
>         if (!genpd_debugfs_dir)
>                 return;
>
> -       d = debugfs_lookup(genpd->name, genpd_debugfs_dir);
> -       debugfs_remove(d);
> +       debugfs_lookup_and_remove(genpd->name, genpd_debugfs_dir);
>  }
>
>  static void genpd_update_accounting(struct generic_pm_domain *genpd)
> --
> 2.39.1
>
  

On Thu, Feb 02, 2023 at 03:23:46PM +0100, Rafael J. Wysocki wrote:
> On Thu, Feb 2, 2023 at 3:15 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > When calling debugfs_lookup() the result must have dput() called on it,
> > otherwise the memory will leak over time.  To make things simpler, just
> > call debugfs_lookup_and_remove() instead which handles all of the logic
> > at
> > once.
> >
> > Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> > Cc: Kevin Hilman <khilman@kernel.org>
> > Cc: Ulf Hansson <ulf.hansson@linaro.org>
> > Cc: Pavel Machek <pavel@ucw.cz>
> > Cc: Len Brown <len.brown@intel.com>
> > Cc: linux-pm@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> >  drivers/base/power/domain.c | 5 +----
> >  1 file changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> > index 967bcf9d415e..6097644ebdc5 100644
> > --- a/drivers/base/power/domain.c
> > +++ b/drivers/base/power/domain.c
> > @@ -220,13 +220,10 @@ static void genpd_debug_add(struct generic_pm_domain *genpd);
> >
> >  static void genpd_debug_remove(struct generic_pm_domain *genpd)
> >  {
> > -       struct dentry *d;
> > -
> >         if (!genpd_debugfs_dir)
> >                 return;
> >
> > -       d = debugfs_lookup(genpd->name, genpd_debugfs_dir);
> > -       debugfs_remove(d);
> > +       debugfs_lookup_and_remove(genpd->name, genpd_debugfs_dir);
> >  }
> >
> >  static void genpd_update_accounting(struct generic_pm_domain *genpd)
> > --
> 
> Does this depend on anything in your tree, or can I apply it?

It does not depend on anything in any of my trees, it's made against
Linus's tree right now so please take it through yours.

thanks!

greg k-h
  

On Thu, Feb 2, 2023 at 4:09 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, Feb 02, 2023 at 03:23:46PM +0100, Rafael J. Wysocki wrote:
> > On Thu, Feb 2, 2023 at 3:15 PM Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> > >
> > > When calling debugfs_lookup() the result must have dput() called on it,
> > > otherwise the memory will leak over time.  To make things simpler, just
> > > call debugfs_lookup_and_remove() instead which handles all of the logic
> > > at
> > > once.
> > >
> > > Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> > > Cc: Kevin Hilman <khilman@kernel.org>
> > > Cc: Ulf Hansson <ulf.hansson@linaro.org>
> > > Cc: Pavel Machek <pavel@ucw.cz>
> > > Cc: Len Brown <len.brown@intel.com>
> > > Cc: linux-pm@vger.kernel.org
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > ---
> > >  drivers/base/power/domain.c | 5 +----
> > >  1 file changed, 1 insertion(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> > > index 967bcf9d415e..6097644ebdc5 100644
> > > --- a/drivers/base/power/domain.c
> > > +++ b/drivers/base/power/domain.c
> > > @@ -220,13 +220,10 @@ static void genpd_debug_add(struct generic_pm_domain *genpd);
> > >
> > >  static void genpd_debug_remove(struct generic_pm_domain *genpd)
> > >  {
> > > -       struct dentry *d;
> > > -
> > >         if (!genpd_debugfs_dir)
> > >                 return;
> > >
> > > -       d = debugfs_lookup(genpd->name, genpd_debugfs_dir);
> > > -       debugfs_remove(d);
> > > +       debugfs_lookup_and_remove(genpd->name, genpd_debugfs_dir);
> > >  }
> > >
> > >  static void genpd_update_accounting(struct generic_pm_domain *genpd)
> > > --
> >
> > Does this depend on anything in your tree, or can I apply it?
>
> It does not depend on anything in any of my trees, it's made against
> Linus's tree right now so please take it through yours.

Applied for 6.3 now, thanks!