From: Colin Ian King <colin.king@canonical.com>
Date: Wed, 30 May 2018 17:41:44 +0100
Subject: drm/amdgpu/df: fix potential array out-of-bounds read
Git-commit: 036286e28e8ece7637cc62934f7dbc89e6656940
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

The comparison with the number of elements in array df_v3_7_channel_number
is off-by-one and can produce an array out-of-bounds read if
fb_channel_number is equal to the number of elements of the array. Fix
this by changing the comparison to >= instead of >.

Detected by CoverityScan, CID#1469489 ("Out-of-bounds read")

Fixes: 13b581502d51 ("drm/amdgpu/df: implement df v3_6 callback functions (v2)")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/df_v3_6.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
+++ b/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
@@ -64,7 +64,7 @@ static u32 df_v3_6_get_hbm_channel_numbe
 	int fb_channel_number;
 
 	fb_channel_number = adev->df_funcs->get_fb_channel_number(adev);
-	if (fb_channel_number > ARRAY_SIZE(df_v3_6_channel_number))
+	if (fb_channel_number >= ARRAY_SIZE(df_v3_6_channel_number))
 		fb_channel_number = 0;
 
 	return df_v3_6_channel_number[fb_channel_number];