From: Arnd Bergmann <arnd@kernel.org> To: Anitha Chrisanthus <anitha.chrisanthus@intel.com>, Edmund Dea <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>, kernel test robot <lkp@intel.com>, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm/kmb: fix array bounds warning Date: Sun, 29 Nov 2020 21:09:08 +0100 [thread overview] Message-ID: <20201129200927.1854104-1-arnd@kernel.org> (raw) 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
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org> To: Anitha Chrisanthus <anitha.chrisanthus@intel.com>, Edmund Dea <edmund.j.dea@intel.com>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Sam Ravnborg <sam@ravnborg.org> Cc: dri-devel@lists.freedesktop.org, kernel test robot <lkp@intel.com>, Arnd Bergmann <arnd@arndb.de>, linux-kernel@vger.kernel.org Subject: [PATCH] drm/kmb: fix array bounds warning Date: Sun, 29 Nov 2020 21:09:08 +0100 [thread overview] Message-ID: <20201129200927.1854104-1-arnd@kernel.org> (raw) 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 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next reply other threads:[~2020-11-29 20:10 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-29 20:09 Arnd Bergmann [this message] 2020-11-29 20:09 ` [PATCH] drm/kmb: fix array bounds warning Arnd Bergmann 2020-11-30 22:19 ` Chrisanthus, Anitha 2020-11-30 22:19 ` Chrisanthus, Anitha 2020-12-05 19:59 ` Sam Ravnborg 2020-12-05 19:59 ` Sam Ravnborg
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