__is_lut_linear() computes the expected value of each entry with
expected = i * MAX_DRM_LUT_VALUE / (size - 1);
If it is ever called with a single-entry LUT, size - 1 is zero and the
kernel takes a divide error (#DE). A LUT with fewer than two entries
cannot describe a linear mapping anyway, so return false early instead
of dividing by zero.
Fixes: 086247a4b2fb ("drm/amd/display: Use 4096 lut entries")
Cc: [email protected]
Signed-off-by: Harry Wentland <[email protected]>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
index 7b68c6846039..26e5c89375a5 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
@@ -471,6 +471,12 @@ bool __is_lut_linear(const struct drm_color_lut *lut,
uint32_t size)
uint32_t expected;
int delta;
+ /* A LUT with fewer than two entries can't be interpolated and would
+ * divide by zero below (size - 1); it can't be treated as linear.
+ */
+ if (size < 2)
+ return false;
+
for (i = 0; i < size; i++) {
/* All color values should equal */
if ((lut[i].red != lut[i].green) || (lut[i].green !=
lut[i].blue))
--
2.55.0
