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From ac1e516d5a4c56bf0cb4a3dfc0672f689131cfd4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Tue, 2 Apr 2019 09:29:35 +0200
Subject: [PATCH] drm/ttm: fix start page for huge page check in ttm_put_pages()
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Git-commit: ac1e516d5a4c56bf0cb4a3dfc0672f689131cfd4
Patch-mainline: v5.1-rc6
References: CVE-2019-19927 bsc#1160147

The first page entry is always the same with itself.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/ttm/ttm_page_alloc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index f77c81db161b..c74147f0cbe3 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -732,7 +732,7 @@ static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 			if (!(flags & TTM_PAGE_FLAG_DMA32) &&
 			    (npages - i) >= HPAGE_PMD_NR) {
-				for (j = 0; j < HPAGE_PMD_NR; ++j)
+				for (j = 1; j < HPAGE_PMD_NR; ++j)
 					if (p++ != pages[i + j])
 					    break;
 
@@ -767,7 +767,7 @@ static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
 			if (!p)
 				break;
 
-			for (j = 0; j < HPAGE_PMD_NR; ++j)
+			for (j = 1; j < HPAGE_PMD_NR; ++j)
 				if (p++ != pages[i + j])
 				    break;
 
-- 
2.16.4