diff mbox series

[RFC,10/28] drm: rcar-du: of: Increase buff size for compatible variable

Message ID 20220112174612.10773-11-biju.das.jz@bp.renesas.com (mailing list archive)
State New, archived
Headers show
Series Add RZ/G2L Display support | expand

Commit Message

Biju Das Jan. 12, 2022, 5:45 p.m. UTC
Increase buff size for compatible variable to avoid stack corruption
with RZ/G2L SoC's(renesas,du-r9a07g044l) which requires a buff size
more than the current allocated size.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_of.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Geert Uytterhoeven Jan. 14, 2022, 10:17 a.m. UTC | #1
Hi Biju,

On Wed, Jan 12, 2022 at 6:46 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> Increase buff size for compatible variable to avoid stack corruption
> with RZ/G2L SoC's(renesas,du-r9a07g044l) which requires a buff size
> more than the current allocated size.
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>

Thanks for your patch!

> --- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> @@ -200,7 +200,7 @@ static void __init rcar_du_of_lvds_patch(const struct of_device_id *of_ids)
>         struct device_node *lvds_node;
>         struct device_node *soc_node;
>         struct device_node *du_node;
> -       char compatible[22];
> +       char compatible[24];
>         const char *soc_name;
>         unsigned int i;
>         int ret;

What about changing the code to use kasprintf() instead, to prevent
this from ever happening again?

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
Biju Das Jan. 14, 2022, 12:54 p.m. UTC | #2
Hi Geert,

Thanks for the feedback.

> Subject: Re: [RFC 10/28] drm: rcar-du: of: Increase buff size for
> compatible variable
> 
> Hi Biju,
> 
> On Wed, Jan 12, 2022 at 6:46 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > Increase buff size for compatible variable to avoid stack corruption
> > with RZ/G2L SoC's(renesas,du-r9a07g044l) which requires a buff size
> > more than the current allocated size.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> 
> Thanks for your patch!
> 
> > --- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > @@ -200,7 +200,7 @@ static void __init rcar_du_of_lvds_patch(const
> struct of_device_id *of_ids)
> >         struct device_node *lvds_node;
> >         struct device_node *soc_node;
> >         struct device_node *du_node;
> > -       char compatible[22];
> > +       char compatible[24];
> >         const char *soc_name;
> >         unsigned int i;
> >         int ret;
> 
> What about changing the code to use kasprintf() instead, to prevent this
> from ever happening again?

OK. Will try to use kasprintf. It took some time to figure out the original corruption
issue with RZ/G2L, where string length "socname-lvds" is beyond the limit.

Regards,
Biju
Laurent Pinchart Jan. 23, 2022, 1:52 p.m. UTC | #3
On Fri, Jan 14, 2022 at 11:17:19AM +0100, Geert Uytterhoeven wrote:
> On Wed, Jan 12, 2022 at 6:46 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > Increase buff size for compatible variable to avoid stack corruption
> > with RZ/G2L SoC's(renesas,du-r9a07g044l) which requires a buff size
> > more than the current allocated size.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> 
> Thanks for your patch!
> 
> > --- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > @@ -200,7 +200,7 @@ static void __init rcar_du_of_lvds_patch(const struct of_device_id *of_ids)
> >         struct device_node *lvds_node;
> >         struct device_node *soc_node;
> >         struct device_node *du_node;
> > -       char compatible[22];
> > +       char compatible[24];
> >         const char *soc_name;
> >         unsigned int i;
> >         int ret;
> 
> What about changing the code to use kasprintf() instead, to prevent
> this from ever happening again?

Or maybe it's time to drop this backward compatibility code altogether ?
Geert Uytterhoeven Jan. 24, 2022, 8:18 a.m. UTC | #4
Hi Laurent,

On Sun, Jan 23, 2022 at 2:52 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> On Fri, Jan 14, 2022 at 11:17:19AM +0100, Geert Uytterhoeven wrote:
> > On Wed, Jan 12, 2022 at 6:46 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > > Increase buff size for compatible variable to avoid stack corruption
> > > with RZ/G2L SoC's(renesas,du-r9a07g044l) which requires a buff size
> > > more than the current allocated size.
> > >
> > > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > > +++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > > @@ -200,7 +200,7 @@ static void __init rcar_du_of_lvds_patch(const struct of_device_id *of_ids)
> > >         struct device_node *lvds_node;
> > >         struct device_node *soc_node;
> > >         struct device_node *du_node;
> > > -       char compatible[22];
> > > +       char compatible[24];
> > >         const char *soc_name;
> > >         unsigned int i;
> > >         int ret;
> >
> > What about changing the code to use kasprintf() instead, to prevent
> > this from ever happening again?
>
> Or maybe it's time to drop this backward compatibility code altogether ?

The last R-Car Gen2 DTS was converted in commit edb0c3affe5214a2
("ARM: dts: r8a7793: Convert to new LVDS DT bindings") in v4.17.
The last RZ/G1 DTS was converted in commit 6a6a797625b5fe85 ("ARM:
dts: r8a7743: Convert to new LVDS DT bindings") in v5.0.

Both are older than commit 58256143cff7c2e0 ("clk: renesas: Remove
R-Car Gen2 legacy DT clock support") in v5.5, so I'd say let's get
rid of it.

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
Laurent Pinchart Jan. 26, 2022, 12:53 a.m. UTC | #5
Hi Geert,

On Mon, Jan 24, 2022 at 09:18:52AM +0100, Geert Uytterhoeven wrote:
> On Sun, Jan 23, 2022 at 2:52 PM Laurent Pinchart wrote:
> > On Fri, Jan 14, 2022 at 11:17:19AM +0100, Geert Uytterhoeven wrote:
> > > On Wed, Jan 12, 2022 at 6:46 PM Biju Das wrote:
> > > > Increase buff size for compatible variable to avoid stack corruption
> > > > with RZ/G2L SoC's(renesas,du-r9a07g044l) which requires a buff size
> > > > more than the current allocated size.
> > > >
> > > > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > >
> > > Thanks for your patch!
> > >
> > > > --- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > > > +++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > > > @@ -200,7 +200,7 @@ static void __init rcar_du_of_lvds_patch(const struct of_device_id *of_ids)
> > > >         struct device_node *lvds_node;
> > > >         struct device_node *soc_node;
> > > >         struct device_node *du_node;
> > > > -       char compatible[22];
> > > > +       char compatible[24];
> > > >         const char *soc_name;
> > > >         unsigned int i;
> > > >         int ret;
> > >
> > > What about changing the code to use kasprintf() instead, to prevent
> > > this from ever happening again?
> >
> > Or maybe it's time to drop this backward compatibility code altogether ?
> 
> The last R-Car Gen2 DTS was converted in commit edb0c3affe5214a2
> ("ARM: dts: r8a7793: Convert to new LVDS DT bindings") in v4.17.
> The last RZ/G1 DTS was converted in commit 6a6a797625b5fe85 ("ARM:
> dts: r8a7743: Convert to new LVDS DT bindings") in v5.0.
> 
> Both are older than commit 58256143cff7c2e0 ("clk: renesas: Remove
> R-Car Gen2 legacy DT clock support") in v5.5, so I'd say let's get
> rid of it.

Let's do so then. Biju, would you drop the compat code in v2, or would
you like me to send patches ?
Biju Das Jan. 26, 2022, 6:55 a.m. UTC | #6
Hi Laurent,

> Subject: Re: [RFC 10/28] drm: rcar-du: of: Increase buff size for
> compatible variable
> 
> Hi Geert,
> 
> On Mon, Jan 24, 2022 at 09:18:52AM +0100, Geert Uytterhoeven wrote:
> > On Sun, Jan 23, 2022 at 2:52 PM Laurent Pinchart wrote:
> > > On Fri, Jan 14, 2022 at 11:17:19AM +0100, Geert Uytterhoeven wrote:
> > > > On Wed, Jan 12, 2022 at 6:46 PM Biju Das wrote:
> > > > > Increase buff size for compatible variable to avoid stack
> > > > > corruption with RZ/G2L SoC's(renesas,du-r9a07g044l) which
> > > > > requires a buff size more than the current allocated size.
> > > > >
> > > > > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > > >
> > > > Thanks for your patch!
> > > >
> > > > > --- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > > > > +++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> > > > > @@ -200,7 +200,7 @@ static void __init rcar_du_of_lvds_patch(const
> struct of_device_id *of_ids)
> > > > >         struct device_node *lvds_node;
> > > > >         struct device_node *soc_node;
> > > > >         struct device_node *du_node;
> > > > > -       char compatible[22];
> > > > > +       char compatible[24];
> > > > >         const char *soc_name;
> > > > >         unsigned int i;
> > > > >         int ret;
> > > >
> > > > What about changing the code to use kasprintf() instead, to
> > > > prevent this from ever happening again?
> > >
> > > Or maybe it's time to drop this backward compatibility code altogether
> ?
> >
> > The last R-Car Gen2 DTS was converted in commit edb0c3affe5214a2
> > ("ARM: dts: r8a7793: Convert to new LVDS DT bindings") in v4.17.
> > The last RZ/G1 DTS was converted in commit 6a6a797625b5fe85 ("ARM:
> > dts: r8a7743: Convert to new LVDS DT bindings") in v5.0.
> >
> > Both are older than commit 58256143cff7c2e0 ("clk: renesas: Remove
> > R-Car Gen2 legacy DT clock support") in v5.5, so I'd say let's get rid
> > of it.
> 
> Let's do so then. Biju, would you drop the compat code in v2, or would you
> like me to send patches ?

Please drop this patch and feel free to send patches, as I am busy with bring
up of RZ/G2UL SoC.

Regards,
Biju
diff mbox series

Patch

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_of.c b/drivers/gpu/drm/rcar-du/rcar_du_of.c
index afef69669bb4..84e73f8df686 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
@@ -200,7 +200,7 @@  static void __init rcar_du_of_lvds_patch(const struct of_device_id *of_ids)
 	struct device_node *lvds_node;
 	struct device_node *soc_node;
 	struct device_node *du_node;
-	char compatible[22];
+	char compatible[24];
 	const char *soc_name;
 	unsigned int i;
 	int ret;