| From 9977f0f164d46613288e0b5778eae500dfe06f31 Mon Sep 17 00:00:00 2001 |
| From: Gerald Schaefer <gerald.schaefer@de.ibm.com> |
| Date: Tue, 12 Feb 2013 13:46:20 -0800 |
| Subject: mm: don't overwrite mm->def_flags in do_mlockall() |
| |
| From: Gerald Schaefer <gerald.schaefer@de.ibm.com> |
| |
| commit 9977f0f164d46613288e0b5778eae500dfe06f31 upstream. |
| |
| With commit 8e72033f2a48 ("thp: make MADV_HUGEPAGE check for |
| mm->def_flags") the VM_NOHUGEPAGE flag may be set on s390 in |
| mm->def_flags for certain processes, to prevent future thp mappings. |
| This would be overwritten by do_mlockall(), which sets it back to 0 with |
| an optional VM_LOCKED flag set. |
| |
| To fix this, instead of overwriting mm->def_flags in do_mlockall(), only |
| the VM_LOCKED flag should be set or cleared. |
| |
| Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> |
| Reported-by: Vivek Goyal <vgoyal@redhat.com> |
| Cc: Andrea Arcangeli <aarcange@redhat.com> |
| Cc: Hugh Dickins <hughd@google.com> |
| Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> |
| Cc: Heiko Carstens <heiko.carstens@de.ibm.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/mlock.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/mm/mlock.c |
| +++ b/mm/mlock.c |
| @@ -517,11 +517,11 @@ SYSCALL_DEFINE2(munlock, unsigned long, |
| static int do_mlockall(int flags) |
| { |
| struct vm_area_struct * vma, * prev = NULL; |
| - unsigned int def_flags = 0; |
| |
| if (flags & MCL_FUTURE) |
| - def_flags = VM_LOCKED; |
| - current->mm->def_flags = def_flags; |
| + current->mm->def_flags |= VM_LOCKED; |
| + else |
| + current->mm->def_flags &= ~VM_LOCKED; |
| if (flags == MCL_FUTURE) |
| goto out; |
| |