From: Andrew Morton <akpm@linux-foundation.org>
Date: Wed, 2 Jun 2021 03:52:49 +0000 (+1000)
Subject: mm-userfaultfd-fix-uffd-wp-special-cases-for-fork-fix
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e7e7fdc2b8331d4d16c2382f5feb0c7ab69bc9c3;p=users%2Fjedix%2Flinux-maple.git

mm-userfaultfd-fix-uffd-wp-special-cases-for-fork-fix

fix it for "mm: Device exclusive memory access".

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Wang Qing <wangqing@vivo.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---

diff --git a/mm/memory.c b/mm/memory.c
index 43db5d2b1e468..ae26cca411872 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -850,8 +850,8 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		 * exclusive entries currently only support private writable
 		 * (ie. COW) mappings.
 		 */
-		VM_BUG_ON(!is_cow_mapping(vma->vm_flags));
-		if (try_restore_exclusive_pte(src_mm, src_pte, vma, addr))
+		VM_BUG_ON(!is_cow_mapping(dst_vma->vm_flags));
+		if (try_restore_exclusive_pte(src_mm, src_pte, dst_vma, addr))
 			return -EBUSY;
 		return -ENOENT;
 	}