[PATCH v2] PM: domains: Ensure genpd_debugfs_dir exists before remove

[PATCH v2] PM: domains: Ensure genpd_debugfs_dir exists before remove

[Hsin-Yi Wang]

Both genpd_debug_add() and genpd_debug_remove() may be called
indirectly by other drivers while genpd_debugfs_dir is not yet
set. For example, drivers can call pm_genpd_init() in probe or
pm_genpd_init() in probe fail/cleanup path:

pm_genpd_init()
 --> genpd_debug_add()

pm_genpd_remove()
 --> genpd_remove()
   --> genpd_debug_remove()

At this time, genpd_debug_init() may not yet be called.

genpd_debug_add() checks that if genpd_debugfs_dir is NULL, it
will return directly. Make sure this is also checked
in pm_genpd_remove(), otherwise components under debugfs root
which has the same name as other components under pm_genpd may
be accidentally removed, since NULL represents debugfs root.

Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
v1->v2: Add more context in commit message
---
 drivers/base/power/domain.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 3e86772d5fac5..5a2e0232862e0 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -222,6 +222,9 @@ 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);
 }
-- 
2.37.0.rc0.161.g10f37bed90-goog

Re: [PATCH v2] PM: domains: Ensure genpd_debugfs_dir exists before remove

[Greg Kroah-Hartman]

On Wed, Jul 06, 2022 at 01:16:49AM +0800, Hsin-Yi Wang wrote:
> Both genpd_debug_add() and genpd_debug_remove() may be called
> indirectly by other drivers while genpd_debugfs_dir is not yet
> set. For example, drivers can call pm_genpd_init() in probe or
> pm_genpd_init() in probe fail/cleanup path:
> 
> pm_genpd_init()
>  --> genpd_debug_add()
> 
> pm_genpd_remove()
>  --> genpd_remove()
>    --> genpd_debug_remove()
> 
> At this time, genpd_debug_init() may not yet be called.
> 
> genpd_debug_add() checks that if genpd_debugfs_dir is NULL, it
> will return directly. Make sure this is also checked
> in pm_genpd_remove(), otherwise components under debugfs root
> which has the same name as other components under pm_genpd may
> be accidentally removed, since NULL represents debugfs root.
> 
> Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---
> v1->v2: Add more context in commit message

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH v2] PM: domains: Ensure genpd_debugfs_dir exists before remove

[AngeloGioacchino Del Regno]

Il 05/07/22 19:16, Hsin-Yi Wang ha scritto:
> Both genpd_debug_add() and genpd_debug_remove() may be called
> indirectly by other drivers while genpd_debugfs_dir is not yet
> set. For example, drivers can call pm_genpd_init() in probe or
> pm_genpd_init() in probe fail/cleanup path:
> 
> pm_genpd_init()
>   --> genpd_debug_add()
> 
> pm_genpd_remove()
>   --> genpd_remove()
>     --> genpd_debug_remove()
> 
> At this time, genpd_debug_init() may not yet be called.
> 
> genpd_debug_add() checks that if genpd_debugfs_dir is NULL, it
> will return directly. Make sure this is also checked
> in pm_genpd_remove(), otherwise components under debugfs root
> which has the same name as other components under pm_genpd may
> be accidentally removed, since NULL represents debugfs root.
> 
> Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Re: [PATCH v2] PM: domains: Ensure genpd_debugfs_dir exists before remove

[Ulf Hansson]

On Tue, 5 Jul 2022 at 19:17, Hsin-Yi Wang <hsinyi@chromium.org> wrote:
>
> Both genpd_debug_add() and genpd_debug_remove() may be called
> indirectly by other drivers while genpd_debugfs_dir is not yet
> set. For example, drivers can call pm_genpd_init() in probe or
> pm_genpd_init() in probe fail/cleanup path:
>
> pm_genpd_init()
>  --> genpd_debug_add()
>
> pm_genpd_remove()
>  --> genpd_remove()
>    --> genpd_debug_remove()
>
> At this time, genpd_debug_init() may not yet be called.
>
> genpd_debug_add() checks that if genpd_debugfs_dir is NULL, it
> will return directly. Make sure this is also checked
> in pm_genpd_remove(), otherwise components under debugfs root
> which has the same name as other components under pm_genpd may
> be accidentally removed, since NULL represents debugfs root.
>
> Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>

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

Kind regards
Uffe

> ---
> v1->v2: Add more context in commit message
> ---
>  drivers/base/power/domain.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 3e86772d5fac5..5a2e0232862e0 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -222,6 +222,9 @@ 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);
>  }
> --
> 2.37.0.rc0.161.g10f37bed90-goog
>

Re: [PATCH v2] PM: domains: Ensure genpd_debugfs_dir exists before remove

[Rafael J. Wysocki]

On Wed, Jul 13, 2022 at 2:02 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> On Tue, 5 Jul 2022 at 19:17, Hsin-Yi Wang <hsinyi@chromium.org> wrote:
> >
> > Both genpd_debug_add() and genpd_debug_remove() may be called
> > indirectly by other drivers while genpd_debugfs_dir is not yet
> > set. For example, drivers can call pm_genpd_init() in probe or
> > pm_genpd_init() in probe fail/cleanup path:
> >
> > pm_genpd_init()
> >  --> genpd_debug_add()
> >
> > pm_genpd_remove()
> >  --> genpd_remove()
> >    --> genpd_debug_remove()
> >
> > At this time, genpd_debug_init() may not yet be called.
> >
> > genpd_debug_add() checks that if genpd_debugfs_dir is NULL, it
> > will return directly. Make sure this is also checked
> > in pm_genpd_remove(), otherwise components under debugfs root
> > which has the same name as other components under pm_genpd may
> > be accidentally removed, since NULL represents debugfs root.
> >
> > Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
> > Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Applied as 5.20 material, thanks!

> > ---
> > v1->v2: Add more context in commit message
> > ---
> >  drivers/base/power/domain.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> > index 3e86772d5fac5..5a2e0232862e0 100644
> > --- a/drivers/base/power/domain.c
> > +++ b/drivers/base/power/domain.c
> > @@ -222,6 +222,9 @@ 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);
> >  }
> > --
> > 2.37.0.rc0.161.g10f37bed90-goog
> >