[PATCH 0/5] add missing of_node_put

[PATCH 0/5] add missing of_node_put

[Julia Lawall]

for_each_child_of_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

The complete semantic patch that fixes this problem is
(http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
iterator name for_each_child_of_node;
@@

 for_each_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
+  of_node_put(child);
?  break;
   ...
}
... when != child

@@
expression root,e;
local idexpression child;
@@

 for_each_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
(
   return child;
|
+  of_node_put(child);
?  return ...;
)
   ...
 }
// </smpl>

---

 arch/arm/kernel/devtree.c             |    1 +
 arch/arm/mach-shmobile/pm-rmobile.c   |    4 +++-
 drivers/power/charger-manager.c       |    4 +++-
 drivers/regulator/of_regulator.c      |    1 +
 drivers/video/backlight/88pm860x_bl.c |    1 +
 5 files changed, 9 insertions(+), 2 deletions(-)

[PATCH 3/5] ARM: shmobile: R-Mobile: add missing of_node_put

[Julia Lawall]

for_each_child_of_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

The semantic patch that fixes this problem is as follows
(http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
@@

 for_each_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
(
   return child;
|
+  of_node_put(child);
?  return ...;
)
   ...
 }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 arch/arm/mach-shmobile/pm-rmobile.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-shmobile/pm-rmobile.c b/arch/arm/mach-shmobile/pm-rmobile.c
index 89068c8..46d0a1d 100644
--- a/arch/arm/mach-shmobile/pm-rmobile.c
+++ b/arch/arm/mach-shmobile/pm-rmobile.c
@@ -313,8 +313,10 @@ static int __init rmobile_add_pm_domains(void __iomem *base,
 		}
 
 		pd = kzalloc(sizeof(*pd), GFP_KERNEL);
-		if (!pd)
+		if (!pd) {
+			of_node_put(np);
 			return -ENOMEM;
+		}
 
 		pd->genpd.name = np->name;
 		pd->base = base;

Re: [PATCH 3/5] ARM: shmobile: R-Mobile: add missing of_node_put

[Simon Horman]

On Sat, Oct 10, 2015 at 02:30:52PM +0200, Julia Lawall wrote:
> for_each_child_of_node performs an of_node_get on each iteration, so
> a break out of the loop requires an of_node_put.
> 
> The semantic patch that fixes this problem is as follows
> (http://coccinelle.lip6.fr):
> 
> // <smpl>
> @@
> expression root,e;
> local idexpression child;
> @@
> 
>  for_each_child_of_node(root, child) {
>    ... when != of_node_put(child)
>        when != e = child
> (
>    return child;
> |
> +  of_node_put(child);
> ?  return ...;
> )
>    ...
>  }
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

Thanks, I have queued this up as a cleanup for v4.4.

Re: [PATCH 3/5] ARM: shmobile: R-Mobile: add missing of_node_put

[Geert Uytterhoeven]

Hi Julia,

On Sat, Oct 10, 2015 at 2:30 PM, Julia Lawall <Julia.Lawall@lip6.fr> wrote:
> --- a/arch/arm/mach-shmobile/pm-rmobile.c
> +++ b/arch/arm/mach-shmobile/pm-rmobile.c
> @@ -313,8 +313,10 @@ static int __init rmobile_add_pm_domains(void __iomem *base,
>                 }
>
>                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
> -               if (!pd)
> +               if (!pd) {
> +                       of_node_put(np);
>                         return -ENOMEM;
> +               }

While technically this patch is correct, the system will be dead anyway if it
ever goes OOM at core_initcall() time.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 3/5] ARM: shmobile: R-Mobile: add missing of_node_put

[Julia Lawall]

On Mon, 12 Oct 2015, Geert Uytterhoeven wrote:

> Hi Julia,
>
> On Sat, Oct 10, 2015 at 2:30 PM, Julia Lawall <Julia.Lawall@lip6.fr> wrote:
> > --- a/arch/arm/mach-shmobile/pm-rmobile.c
> > +++ b/arch/arm/mach-shmobile/pm-rmobile.c
> > @@ -313,8 +313,10 @@ static int __init rmobile_add_pm_domains(void __iomem *base,
> >                 }
> >
> >                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
> > -               if (!pd)
> > +               if (!pd) {
> > +                       of_node_put(np);
> >                         return -ENOMEM;
> > +               }
>
> While technically this patch is correct, the system will be dead anyway if it
> ever goes OOM at core_initcall() time.

Maybe it would be better for the code to be correct to serve as an example
(or to avoid serving as a bad example) for others?

julia

Re: [PATCH 3/5] ARM: shmobile: R-Mobile: add missing of_node_put

[Geert Uytterhoeven]

Hi Julia,

On Mon, Oct 12, 2015 at 9:24 AM, Julia Lawall <julia.lawall@lip6.fr> wrote:
> On Mon, 12 Oct 2015, Geert Uytterhoeven wrote:
>> On Sat, Oct 10, 2015 at 2:30 PM, Julia Lawall <Julia.Lawall@lip6.fr> wrote:
>> > --- a/arch/arm/mach-shmobile/pm-rmobile.c
>> > +++ b/arch/arm/mach-shmobile/pm-rmobile.c
>> > @@ -313,8 +313,10 @@ static int __init rmobile_add_pm_domains(void __iomem *base,
>> >                 }
>> >
>> >                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
>> > -               if (!pd)
>> > +               if (!pd) {
>> > +                       of_node_put(np);
>> >                         return -ENOMEM;
>> > +               }
>>
>> While technically this patch is correct, the system will be dead anyway if it
>> ever goes OOM at core_initcall() time.
>
> Maybe it would be better for the code to be correct to serve as an example
> (or to avoid serving as a bad example) for others?

Sure, as it's only a single call, that's fine for me.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 3/5] ARM: shmobile: R-Mobile: add missing of_node_put

[Thomas Petazzoni]

Dear Geert Uytterhoeven,

On Mon, 12 Oct 2015 09:18:52 +0200, Geert Uytterhoeven wrote:

> >                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
> > -               if (!pd)
> > +               if (!pd) {
> > +                       of_node_put(np);
> >                         return -ENOMEM;
> > +               }
> 
> While technically this patch is correct, the system will be dead anyway if it
> ever goes OOM at core_initcall() time.

Then BUG_ON(!pd); ?

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

Re: [PATCH 3/5] ARM: shmobile: R-Mobile: add missing of_node_put

[Geert Uytterhoeven]

On Mon, Oct 12, 2015 at 9:29 AM, Thomas Petazzoni
<thomas.petazzoni@free-electrons.com> wrote:
> On Mon, 12 Oct 2015 09:18:52 +0200, Geert Uytterhoeven wrote:
>
>> >                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
>> > -               if (!pd)
>> > +               if (!pd) {
>> > +                       of_node_put(np);
>> >                         return -ENOMEM;
>> > +               }
>>
>> While technically this patch is correct, the system will be dead anyway if it
>> ever goes OOM at core_initcall() time.
>
> Then BUG_ON(!pd); ?

kzalloc() will scream anyway.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds