linux-kernel - [PATCH 1/2] x86/mm: fix vmalloc_fault to use pXd

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Date:   Tue, 13 Mar 2018 11:03:46 -0600
From:   Toshi Kani <toshi.kani@....com>
To:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com
Cc:     bp@...en8.de, luto@...nel.org, gratian.crisan@...com,
        x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Toshi Kani <toshi.kani@....com>, stable@...r.kernel.org
Subject: [PATCH 1/2] x86/mm: fix vmalloc_fault to use pXd_large

Gratian Crisan reported that vmalloc_fault() crashes when
CONFIG_HUGETLBFS is not set since the function inadvertently
uses pXn_huge(), which always return 0 in this case.  ioremap()
does not depend on CONFIG_HUGETLBFS.

Fix vmalloc_fault() to call pXd_large() instead.

fixes: f4eafd8bcd52 ("x86/mm: Fix vmalloc_fault() to handle large pages properly")
Reported-by: Gratian Crisan <gratian.crisan@...com>
Signed-off-by: Toshi Kani <toshi.kani@....com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Gratian Crisan <gratian.crisan@...com>
Cc: stable@...r.kernel.org
---
 arch/x86/mm/fault.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index c88573d90f3e..25a30b5d6582 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -330,7 +330,7 @@ static noinline int vmalloc_fault(unsigned long address)
 	if (!pmd_k)
 		return -1;
 
-	if (pmd_huge(*pmd_k))
+	if (pmd_large(*pmd_k))
 		return 0;
 
 	pte_k = pte_offset_kernel(pmd_k, address);
@@ -475,7 +475,7 @@ static noinline int vmalloc_fault(unsigned long address)
 	if (pud_none(*pud) || pud_pfn(*pud) != pud_pfn(*pud_ref))
 		BUG();
 
-	if (pud_huge(*pud))
+	if (pud_large(*pud))
 		return 0;
 
 	pmd = pmd_offset(pud, address);
@@ -486,7 +486,7 @@ static noinline int vmalloc_fault(unsigned long address)
 	if (pmd_none(*pmd) || pmd_pfn(*pmd) != pmd_pfn(*pmd_ref))
 		BUG();
 
-	if (pmd_huge(*pmd))
+	if (pmd_large(*pmd))
 		return 0;
 
 	pte_ref = pte_offset_kernel(pmd_ref, address);