From patchwork Tue Feb 19 18:49:40 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [77/81] mm: don't overwrite mm->def_flags in do_mlockall() From: Herton Ronaldo Krzesinski X-Patchwork-Id: 222067 Message-Id: <1361299784-8830-78-git-send-email-herton.krzesinski@canonical.com> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Andrea Arcangeli , Hugh Dickins , Heiko Carstens , Martin Schwidefsky , Andrew Morton , Linus Torvalds , Gerald Schaefer Date: Tue, 19 Feb 2013 15:49:40 -0300 3.5.7.6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Gerald Schaefer 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 Reported-by: Vivek Goyal Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Martin Schwidefsky Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Herton Ronaldo Krzesinski --- 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;