x86/ldt: Fix support_pte_mask filtering in map_ldt_struct()

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

[ The bug was also independently reported by Shuah Khan ]

Fixes: fb43d6cb91ef ('x86/mm: Do not auto-massage page protections')
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

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);