The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 90a3d22ff02b196d5884e111f39271a1d4ee8e3e Mon Sep 17 00:00:00 2001 From: Dan Carpenter dan.carpenter@oracle.com Date: Mon, 24 Jan 2022 15:24:09 +0300 Subject: [PATCH] drm/i915/overlay: Prevent divide by zero bugs in scaling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

Smatch detected a divide by zero bug in check_overlay_scaling().

drivers/gpu/drm/i915/display/intel_overlay.c:976 check_overlay_scaling() error: potential divide by zero bug '/ rec->dst_height'. drivers/gpu/drm/i915/display/intel_overlay.c:980 check_overlay_scaling() error: potential divide by zero bug '/ rec->dst_width'.

Prevent this by ensuring that the dst height and width are non-zero.

Fixes: 02e792fbaadb ("drm/i915: implement drmmode overlay support v4") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20220124122409.GA31673@kili (cherry picked from commit cf5b64f7f10b28bebb9b7c9d25e7aee5cbe43918) Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c index 1a376e9a1ff3..d610e48cab94 100644 --- a/drivers/gpu/drm/i915/display/intel_overlay.c +++ b/drivers/gpu/drm/i915/display/intel_overlay.c @@ -959,6 +959,9 @@ static int check_overlay_dst(struct intel_overlay *overlay, const struct intel_crtc_state *pipe_config = overlay->crtc->config;

+ if (rec->dst_height == 0 || rec->dst_width == 0) + return -EINVAL; + if (rec->dst_x < pipe_config->pipe_src_w && rec->dst_x + rec->dst_width <= pipe_config->pipe_src_w && rec->dst_y < pipe_config->pipe_src_h &&