From 06b74c85468afcb3c2fd4f9a63e54aaa84816f60 Mon Sep 17 00:00:00 2001
From: Alex Hung <alex.hung@amd.com>
Date: Tue, 18 Jun 2024 16:21:20 -0600
Subject: [PATCH] drm/amd/display: Check denominator pbn_div before used

BugLink: https://bugs.launchpad.net/bugs/2085849

[ Upstream commit 116a678f3a9abc24f5c9d2525b7393d18d9eb58e ]

[WHAT & HOW]
A denominator cannot be 0, and is checked before used.

This fixes 1 DIVIDE_BY_ZERO issue reported by Coverity.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
CVE-2024-46773
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index b7163ea4b2a0..e54533cfd440 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7234,7 +7234,7 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state,
 			}
 		}
 
-		if (j == dc_state->stream_count)
+		if (j == dc_state->stream_count || pbn_div == 0)
 			continue;
 
 		slot_num = DIV_ROUND_UP(pbn, pbn_div);