The patch titled
Subject: userfaultfd: non-cooperative: wake userfaults after UFFDIO_UNREGISTER
has been removed from the -mm tree. Its filename was
userfaultfd-non-cooperative-wake-userfaults-after-uffdio_unregister.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Subject: userfaultfd: non-cooperative: wake userfaults after UFFDIO_UNREGISTER
Userfaults may still happen after the userfaultfd monitor thread received
a UFFD_EVENT_MADVDONTNEED until UFFDIO_UNREGISTER is run.
Wake any pending userfault within UFFDIO_UNREGISTER protected by the
mmap_sem for writing, so they will not be reported to userland leading to
UFFDIO_COPY returning -EINVAL (as the range was already unregistered) and
they will not hang permanently either.
Link: http://lkml.kernel.org/r/20161216144821.5183-16-aarcange@xxxxxxxxxx
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Michael Rapoport <RAPOPORT@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff -puN fs/userfaultfd.c~userfaultfd-non-cooperative-wake-userfaults-after-uffdio_unregister fs/userfaultfd.c
--- a/fs/userfaultfd.c~userfaultfd-non-cooperative-wake-userfaults-after-uffdio_unregister
+++ a/fs/userfaultfd.c
@@ -1302,6 +1302,19 @@ static int userfaultfd_unregister(struct
start = vma->vm_start;
vma_end = min(end, vma->vm_end);
+ if (userfaultfd_missing(vma)) {
+ /*
+ * Wake any concurrent pending userfault while
+ * we unregister, so they will not hang
+ * permanently and it avoids userland to call
+ * UFFDIO_WAKE explicitly.
+ */
+ struct userfaultfd_wake_range range;
+ range.start = start;
+ range.len = vma_end - start;
+ wake_userfault(vma->vm_userfaultfd_ctx.ctx, &range);
+ }
+
new_flags = vma->vm_flags & ~(VM_UFFD_MISSING | VM_UFFD_WP);
prev = vma_merge(mm, prev, start, vma_end, new_flags,
vma->anon_vma, vma->vm_file, vma->vm_pgoff,
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
userfaultfd-mcopy_atomic-return-enoent-when-no-compatible-vma-found-fix-2.patch
userfaultfd-mcopy_atomic-return-enoent-when-no-compatible-vma-found-fix-2-fix-fix.patch
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