[PATCH] x86/ldt: Fix support_pte_mask filtering in map_ldt_struct()

Joerg Roedel
2018-04-16T09:44:04Z

From: Joerg Roedel <jroedel@suse.de>

The |= operator will let us end up with an invalid PTE. Use
the correct &= instead.

Fixes: fb43d6cb91ef ('x86/mm: Do not auto-massage page protections')
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kernel/ldt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index d41d896481b8..c9b14020f4dd 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -166,7 +166,7 @@ map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot)
*/
pte_prot = __pgprot(__PAGE_KERNEL_RO & ~_PAGE_GLOBAL);
/* Filter out unsuppored __PAGE_KERNEL* bits: */
- pgprot_val(pte_prot) |= __supported_pte_mask;
+ pgprot_val(pte_prot) &= __supported_pte_mask;
pte = pfn_pte(pfn, pte_prot);
set_pte_at(mm, va, ptep, pte);
pte_unmap_unlock(ptep, ptl);
--
2.13.6