linux-kernel - [PATCH v3 10/21] x86/kaslr: Fix off-by-one error in process_gb_huge

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Message-Id: <20200728225722.67457-11-nivedita@alum.mit.edu>
Date:   Tue, 28 Jul 2020 18:57:11 -0400
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Kees Cook <keescook@...omium.org>, x86@...nel.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH v3 10/21] x86/kaslr: Fix off-by-one error in process_gb_huge_pages

If the remaining size of the region is exactly 1Gb, there is still one
hugepage that can be reserved.

Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
---
 arch/x86/boot/compressed/kaslr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index d074986e8061..0df513e3e2ce 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -562,7 +562,7 @@ process_gb_huge_pages(struct mem_vector *region, unsigned long image_size)
 		size = region->size - (addr - region->start);
 
 	/* Check how many 1GB huge pages can be filtered out: */
-	while (size > PUD_SIZE && max_gb_huge_pages) {
+	while (size >= PUD_SIZE && max_gb_huge_pages) {
 		size -= PUD_SIZE;
 		max_gb_huge_pages--;
 		i++;
-- 
2.26.2