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.

Possible dependencies:

2e786eb2f9ce ("drm/msm/dsi: fix memory corruption with too many bridges") 52749d601a60 ("drm/msm/dsi: Fix potential NULL pointer dereference in msm_dsi_modeset_init")

thanks,

greg k-h

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

From 2e786eb2f9cebb07e317226b60054df510b60c65 Mon Sep 17 00:00:00 2001 From: Johan Hovold johan+linaro@kernel.org Date: Tue, 13 Sep 2022 10:53:13 +0200 Subject: [PATCH] drm/msm/dsi: fix memory corruption with too many bridges

Add the missing sanity check on the bridge counter to avoid corrupting data beyond the fixed-sized bridge array in case there are ever more than eight bridges.

Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support") Cc: stable@vger.kernel.org # 4.1 Signed-off-by: Johan Hovold johan+linaro@kernel.org Tested-by: Kuogee Hsieh quic_khsieh@quicinc.com Reviewed-by: Kuogee Hsieh quic_khsieh@quicinc.com Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Patchwork: https://patchwork.freedesktop.org/patch/502668/ Link: https://lore.kernel.org/r/20220913085320.8577-4-johan+linaro@kernel.org Signed-off-by: Abhinav Kumar quic_abhinavk@quicinc.com

diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c index 39bbabb5daf6..8a95c744972a 100644 --- a/drivers/gpu/drm/msm/dsi/dsi.c +++ b/drivers/gpu/drm/msm/dsi/dsi.c @@ -218,6 +218,12 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev, return -EINVAL;

priv = dev->dev_private; + + if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) { + DRM_DEV_ERROR(dev->dev, "too many bridges\n"); + return -ENOSPC; + } + msm_dsi->dev = dev;

ret = msm_dsi_host_modeset_init(msm_dsi->host, dev);