From 433480c1afd44f3e1e664b85063d98cefeefa0ed Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Fri, 22 Nov 2019 19:56:20 +0200 Subject: [PATCH] drm/rect: Avoid division by zero MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Check for zero width/height destination rectangle in drm_rect_clip_scaled() to avoid a division by zero. Cc: stable@vger.kernel.org Fixes: f96bdf564f3e ("drm/rect: Handle rounding errors in drm_rect_clip_scaled, v3.") Cc: Maarten Lankhorst Cc: Benjamin Gaignard Cc: Daniel Vetter Testcase: igt/kms_selftest/drm_rect_clip_scaled_div_by_zero Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20191122175623.13565-2-ville.syrjala@linux.intel.com Reviewed-by: Daniel Vetter Reviewed-by: Benjamin Gaignard --- drivers/gpu/drm/drm_rect.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c index b8363aaa9032..818738e83d06 100644 --- a/drivers/gpu/drm/drm_rect.c +++ b/drivers/gpu/drm/drm_rect.c @@ -54,7 +54,12 @@ EXPORT_SYMBOL(drm_rect_intersect); static u32 clip_scaled(u32 src, u32 dst, u32 clip) { - u64 tmp = mul_u32_u32(src, dst - clip); + u64 tmp; + + if (dst == 0) + return 0; + + tmp = mul_u32_u32(src, dst - clip); /* * Round toward 1.0 when clipping so that we don't accidentally