3.5.7.6 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Gerald Schaefer <gerald.schae...@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.schae...@de.ibm.com>
Reported-by: Vivek Goyal <vgo...@redhat.com>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Hugh Dickins <hu...@google.com>
Cc: Martin Schwidefsky <schwidef...@de.ibm.com>
Cc: Heiko Carstens <heiko.carst...@de.ibm.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesin...@canonical.com>
---
mm/mlock.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/mlock.c b/mm/mlock.c
index ef726e8..3283272 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -524,11 +524,11 @@ 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;
--
1.7.9.5
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