From a66477b0efe511d98dde3e4aaeb189790e6f0a39 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Christian=20K=C3=B6nig?= Date: Tue, 2 Apr 2019 09:26:52 +0200 Subject: [PATCH] drm/ttm: fix out-of-bounds read in ttm_put_pages() v2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When ttm_put_pages() tries to figure out whether it's dealing with transparent hugepages, it just reads past the bounds of the pages array without a check. v2: simplify the test if enough pages are left in the array (Christian). Signed-off-by: Jann Horn Signed-off-by: Christian König Fixes: 5c42c64f7d54 ("drm/ttm: fix the fix for huge compound pages") Cc: stable@vger.kernel.org Reviewed-by: Michel Dänzer Reviewed-by: Junwei Zhang Reviewed-by: Huang Rui Signed-off-by: Alex Deucher --- drivers/gpu/drm/ttm/ttm_page_alloc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c index f841accc2c00..f77c81db161b 100644 --- a/drivers/gpu/drm/ttm/ttm_page_alloc.c +++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c @@ -730,7 +730,8 @@ static void ttm_put_pages(struct page **pages, unsigned npages, int flags, } #ifdef CONFIG_TRANSPARENT_HUGEPAGE - if (!(flags & TTM_PAGE_FLAG_DMA32)) { + if (!(flags & TTM_PAGE_FLAG_DMA32) && + (npages - i) >= HPAGE_PMD_NR) { for (j = 0; j < HPAGE_PMD_NR; ++j) if (p++ != pages[i + j]) break; @@ -759,7 +760,7 @@ static void ttm_put_pages(struct page **pages, unsigned npages, int flags, unsigned max_size, n2free; spin_lock_irqsave(&huge->lock, irq_flags); - while (i < npages) { + while ((npages - i) >= HPAGE_PMD_NR) { struct page *p = pages[i]; unsigned j; -- 2.11.0