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authorGerald Schaefer <gerald.schaefer@de.ibm.com>2013-02-12 13:46:20 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-17 10:53:12 -0800
commit422224746ba5bf508e66b6f4e2cd18ad878a4637 (patch)
tree52ccb93adebb180e8b2d51395ec1a6ace2e47ab4
parent047b1c0f49ea608e3ca0de2775957f061a0c2737 (diff)
mm: don't overwrite mm->def_flags in do_mlockall()
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>
-rw-r--r--mm/mlock.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index f0b9ce572fc7..c9bd528b01d2 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;