From 9977f0f164d46613288e0b5778eae500dfe06f31 Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Tue, 12 Feb 2013 13:46:20 -0800 Subject: mm: don't overwrite mm->def_flags in do_mlockall() 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 Reported-by: Vivek Goyal Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mlock.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/mlock.c b/mm/mlock.c index f0b9ce572fc..c9bd528b01d 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -517,11 +517,11 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) 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; -- cgit v1.2.3