From: Yannick Fertré Date: Wed, 3 Apr 2019 09:20:16 +0000 (+0200) Subject: drm/stm: ltdc: limit number of layer to avoid memory overflow X-Git-Tag: v5.3-rc1~81^2~27^2~113 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=77756ad6d08fb3f276d357be4c318f871dab8734;p=linux.git drm/stm: ltdc: limit number of layer to avoid memory overflow If the number of layer is greater than LTDC_MAX_LAYER, we can have memory overflow when reading plane_fpsi[]. Signed-off-by: Yannick Fertré Acked-by: Philippe Cornu Signed-off-by: Benjamin Gaignard Link: https://patchwork.freedesktop.org/patch/msgid/1554283216-2700-1-git-send-email-yannick.fertre@st.com --- diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c index cde2f18ce1c1..17438c28d9fc 100644 --- a/drivers/gpu/drm/stm/ltdc.c +++ b/drivers/gpu/drm/stm/ltdc.c @@ -1021,10 +1021,13 @@ static int ltdc_get_caps(struct drm_device *ddev) struct ltdc_device *ldev = ddev->dev_private; u32 bus_width_log2, lcr, gc2r; - /* at least 1 layer must be managed */ + /* + * at least 1 layer must be managed & the number of layers + * must not exceed LTDC_MAX_LAYER + */ lcr = reg_read(ldev->regs, LTDC_LCR); - ldev->caps.nb_layers = max_t(int, lcr, 1); + ldev->caps.nb_layers = clamp((int)lcr, 1, LTDC_MAX_LAYER); /* set data bus width */ gc2r = reg_read(ldev->regs, LTDC_GC2R);