The patch titled
Subject: userfaultfd_copy: return -ENOSPC in case mm has gone
has been added to the -mm tree. Its filename is
userfaultfd_copy-return-enospc-in-case-mm-has-gone.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd_copy-return-enospc-in-case-mm-has-gone.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd_copy-return-enospc-in-case-mm-has-gone.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Subject: userfaultfd_copy: return -ENOSPC in case mm has gone
In the non-cooperative userfaultfd case, the process exit may race with
outstanding mcopy_atomic called by the uffd monitor. Returning -ENOSPC
instead of -EINVAL when mm is already gone will allow uffd monitor to
distinguish this case from other error conditions.
Link: http://lkml.kernel.org/r/1485542673-24387-6-git-send-email-rppt@xxxxxxxxxxxxxxxxxx
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN fs/userfaultfd.c~userfaultfd_copy-return-enospc-in-case-mm-has-gone fs/userfaultfd.c
--- a/fs/userfaultfd.c~userfaultfd_copy-return-enospc-in-case-mm-has-gone
+++ a/fs/userfaultfd.c
@@ -1603,6 +1603,8 @@ static int userfaultfd_copy(struct userf
ret = mcopy_atomic(ctx->mm, uffdio_copy.dst, uffdio_copy.src,
uffdio_copy.len);
mmput(ctx->mm);
+ } else {
+ return -ENOSPC;
}
if (unlikely(put_user(ret, &user_uffdio_copy->copy)))
return -EFAULT;
_
Patches currently in -mm which might be from rppt@xxxxxxxxxxxxxxxxxx are
userfaultfd-non-cooperative-dup_userfaultfd-use-mm_count-instead-of-mm_users.patch
userfaultfd-introduce-vma_can_userfault.patch
userfaultfd-shmem-add-shmem_mcopy_atomic_pte-for-userfaultfd-support.patch
userfaultfd-shmem-introduce-vma_is_shmem.patch
userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory.patch
userfaultfd-shmem-add-userfaultfd-hook-for-shared-memory-faults.patch
userfaultfd-shmem-allow-registration-of-shared-memory-ranges.patch
userfaultfd-shmem-add-userfaultfd_shmem-test.patch
userfaultfd-non-cooperative-selftest-introduce-userfaultfd_open.patch
userfaultfd-non-cooperative-selftest-add-ufd-parameter-to-copy_page.patch
userfaultfd-non-cooperative-selftest-add-test-for-fork-madvdontneed-and-remap-events.patch
userfaultfd-non-cooperative-rename-event_madvdontneed-to-event_remove.patch
userfaultfd-non-cooperative-add-madvise-event-for-madv_remove-request.patch
userfaultfd-non-cooperative-selftest-enable-remove-event-test-for-shmem.patch
mm-call-vm_munmap-in-munmap-syscall-instead-of-using-open-coded-version.patch
userfaultfd-non-cooperative-add-event-for-memory-unmaps.patch
userfaultfd-non-cooperative-add-event-for-exit-notification.patch
userfaultfd-mcopy_atomic-return-enoent-when-no-compatible-vma-found.patch
userfaultfd_copy-return-enospc-in-case-mm-has-gone.patch
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