From: Arnd Bergmann Date: Sun, 29 Nov 2020 20:09:08 +0000 (+0100) Subject: drm/kmb: fix array bounds warning X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=98fdd0042c7c82e0b4bca6100eec35f73b48878d;p=linux.git drm/kmb: fix array bounds warning 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 Signed-off-by: Arnd Bergmann Reviewed-by: Anitha Chrisanthus Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20201129200927.1854104-1-arnd@kernel.org --- diff --git a/drivers/gpu/drm/kmb/kmb_plane.c b/drivers/gpu/drm/kmb/kmb_plane.c index 8448d1edb553e..be8eea3830c1b 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;