* [PATCH] drm/kmb: fix array bounds warning
@ 2020-11-29 20:09 Arnd Bergmann
2020-11-30 22:19 ` Chrisanthus, Anitha
0 siblings, 1 reply; 3+ messages in thread
From: Arnd Bergmann @ 2020-11-29 20:09 UTC (permalink / raw)
To: Anitha Chrisanthus, Edmund Dea, David Airlie, Daniel Vetter,
Sam Ravnborg
Cc: Arnd Bergmann, kernel test robot, dri-devel, linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
gcc warns about an out-of-bounds access when the using nonzero
values for 'plane_id' on kmb->plane_status:
drivers/gpu/drm/kmb/kmb_plane.c: In function 'kmb_plane_atomic_disable':
drivers/gpu/drm/kmb/kmb_plane.c:128:20: warning: array subscript 3 is above array bounds of 'struct layer_status[1]' [-Warray-bounds]
128 | kmb->plane_status[plane_id].ctrl = LCD_CTRL_GL2_ENABLE;
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~
drivers/gpu/drm/kmb/kmb_plane.c:125:20: warning: array subscript 2 is above array bounds of 'struct layer_status[1]' [-Warray-bounds]
125 | kmb->plane_status[plane_id].ctrl = LCD_CTRL_GL1_ENABLE;
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~
drivers/gpu/drm/kmb/kmb_plane.c:122:20: warning: array subscript 1 is above array bounds of 'struct layer_status[1]' [-Warray-bounds]
122 | kmb->plane_status[plane_id].ctrl = LCD_CTRL_VL2_ENABLE;
Having the array truncated to one entry seems intentional, so add
a range check before indexing it to make it clearer what is going
on and shut up the warning.
I received the warning from the kernel test robot after a private
patch that turns on Warray-bounds unconditionally.
Fixes: 7f7b96a8a0a1 ("drm/kmb: Add support for KeemBay Display")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/gpu/drm/kmb/kmb_plane.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/kmb/kmb_plane.c b/drivers/gpu/drm/kmb/kmb_plane.c
index 8448d1edb553..be8eea3830c1 100644
--- a/drivers/gpu/drm/kmb/kmb_plane.c
+++ b/drivers/gpu/drm/kmb/kmb_plane.c
@@ -114,6 +114,9 @@ static void kmb_plane_atomic_disable(struct drm_plane *plane,
kmb = to_kmb(plane->dev);
+ if (WARN_ON(plane_id >= KMB_MAX_PLANES))
+ return;
+
switch (plane_id) {
case LAYER_0:
kmb->plane_status[plane_id].ctrl = LCD_CTRL_VL1_ENABLE;
--
2.27.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH] drm/kmb: fix array bounds warning
2020-11-29 20:09 [PATCH] drm/kmb: fix array bounds warning Arnd Bergmann
@ 2020-11-30 22:19 ` Chrisanthus, Anitha
2020-12-05 19:59 ` Sam Ravnborg
0 siblings, 1 reply; 3+ messages in thread
From: Chrisanthus, Anitha @ 2020-11-30 22:19 UTC (permalink / raw)
To: Arnd Bergmann, Dea, Edmund J, David Airlie, Daniel Vetter, Sam Ravnborg
Cc: Arnd Bergmann, lkp, dri-devel, linux-kernel
Hi Arnd,
Thanks for your patch.
> -----Original Message-----
> From: Arnd Bergmann <arnd@kernel.org>
> Sent: Sunday, November 29, 2020 12:09 PM
> To: Chrisanthus, Anitha <anitha.chrisanthus@intel.com>; Dea, Edmund J
> <edmund.j.dea@intel.com>; David Airlie <airlied@linux.ie>; Daniel Vetter
> <daniel@ffwll.ch>; Sam Ravnborg <sam@ravnborg.org>
> Cc: Arnd Bergmann <arnd@arndb.de>; lkp <lkp@intel.com>; dri-
> devel@lists.freedesktop.org; linux-kernel@vger.kernel.org
> Subject: [PATCH] drm/kmb: fix array bounds warning
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> gcc warns about an out-of-bounds access when the using nonzero
> values for 'plane_id' on kmb->plane_status:
>
> drivers/gpu/drm/kmb/kmb_plane.c: In function 'kmb_plane_atomic_disable':
> drivers/gpu/drm/kmb/kmb_plane.c:128:20: warning: array subscript 3 is
> above array bounds of 'struct layer_status[1]' [-Warray-bounds]
> 128 | kmb->plane_status[plane_id].ctrl = LCD_CTRL_GL2_ENABLE;
> | ~~~~~~~~~~~~~~~~~^~~~~~~~~~
> drivers/gpu/drm/kmb/kmb_plane.c:125:20: warning: array subscript 2 is
> above array bounds of 'struct layer_status[1]' [-Warray-bounds]
> 125 | kmb->plane_status[plane_id].ctrl = LCD_CTRL_GL1_ENABLE;
> | ~~~~~~~~~~~~~~~~~^~~~~~~~~~
> drivers/gpu/drm/kmb/kmb_plane.c:122:20: warning: array subscript 1 is
> above array bounds of 'struct layer_status[1]' [-Warray-bounds]
> 122 | kmb->plane_status[plane_id].ctrl = LCD_CTRL_VL2_ENABLE;
>
> Having the array truncated to one entry seems intentional, so add
> a range check before indexing it to make it clearer what is going
> on and shut up the warning.
>
> I received the warning from the kernel test robot after a private
> patch that turns on Warray-bounds unconditionally.
>
> Fixes: 7f7b96a8a0a1 ("drm/kmb: Add support for KeemBay Display")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/gpu/drm/kmb/kmb_plane.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/kmb/kmb_plane.c
> b/drivers/gpu/drm/kmb/kmb_plane.c
> index 8448d1edb553..be8eea3830c1 100644
> --- a/drivers/gpu/drm/kmb/kmb_plane.c
> +++ b/drivers/gpu/drm/kmb/kmb_plane.c
> @@ -114,6 +114,9 @@ static void kmb_plane_atomic_disable(struct
> drm_plane *plane,
>
> kmb = to_kmb(plane->dev);
>
> + if (WARN_ON(plane_id >= KMB_MAX_PLANES))
> + return;
> +
Looks good.
Reviewed-by: Anitha Chrisanthus <anitha.chrisanthus@intel.com>
> switch (plane_id) {
> case LAYER_0:
> kmb->plane_status[plane_id].ctrl = LCD_CTRL_VL1_ENABLE;
> --
> 2.27.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/kmb: fix array bounds warning
2020-11-30 22:19 ` Chrisanthus, Anitha
@ 2020-12-05 19:59 ` Sam Ravnborg
0 siblings, 0 replies; 3+ messages in thread
From: Sam Ravnborg @ 2020-12-05 19:59 UTC (permalink / raw)
To: Chrisanthus, Anitha
Cc: Arnd Bergmann, Dea, Edmund J, David Airlie, Daniel Vetter,
dri-devel, lkp, Arnd Bergmann, linux-kernel
Hi Anitha,
On Mon, Nov 30, 2020 at 10:19:13PM +0000, Chrisanthus, Anitha wrote:
> Hi Arnd,
> Thanks for your patch.
>
> > -----Original Message-----
> > From: Arnd Bergmann <arnd@kernel.org>
> > Sent: Sunday, November 29, 2020 12:09 PM
> > To: Chrisanthus, Anitha <anitha.chrisanthus@intel.com>; Dea, Edmund J
> > <edmund.j.dea@intel.com>; David Airlie <airlied@linux.ie>; Daniel Vetter
> > <daniel@ffwll.ch>; Sam Ravnborg <sam@ravnborg.org>
> > Cc: Arnd Bergmann <arnd@arndb.de>; lkp <lkp@intel.com>; dri-
> > devel@lists.freedesktop.org; linux-kernel@vger.kernel.org
> > Subject: [PATCH] drm/kmb: fix array bounds warning
> >
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > gcc warns about an out-of-bounds access when the using nonzero
> > values for 'plane_id' on kmb->plane_status:
...
> Looks good.
>
> Reviewed-by: Anitha Chrisanthus <anitha.chrisanthus@intel.com>
You wanted a little time to get comforable with dim, so I picked up this
patch and pushed it to drm-misc-next.
Sam
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-11-30 22:19 ` Chrisanthus, Anitha
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