The patch titled
Subject: userfaultfd: non-cooperative: flush event_wqh at release time
has been added to the -mm tree. Its filename is
userfaultfd-non-cooperative-flush-event_wqh-at-release-time.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-non-cooperative-flush-event_wqh-at-release-time.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-non-cooperative-flush-event_wqh-at-release-time.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Subject: userfaultfd: non-cooperative: flush event_wqh at release time
There may still be threads waiting on event_wqh at the time the userfault
file descriptor is closed. Flush the events wait-queue to prevent waiting
threads from hanging.
Link: http://lkml.kernel.org/r/1501398127-30419-1-git-send-email-rppt@xxxxxxxxxxxxxxxxxx
Fixes: 9cd75c3cd4c3d ("userfaultfd: non-cooperative: add ability to report
non-PF events from uffd descriptor")
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN fs/userfaultfd.c~userfaultfd-non-cooperative-flush-event_wqh-at-release-time fs/userfaultfd.c
--- a/fs/userfaultfd.c~userfaultfd-non-cooperative-flush-event_wqh-at-release-time
+++ a/fs/userfaultfd.c
@@ -854,6 +854,9 @@ wakeup:
__wake_up_locked_key(&ctx->fault_wqh, TASK_NORMAL, &range);
spin_unlock(&ctx->fault_pending_wqh.lock);
+ /* Flush pending events that may still wait on event_wqh */
+ wake_up_all(&ctx->event_wqh);
+
wake_up_poll(&ctx->fd_wqh, POLLHUP);
userfaultfd_ctx_put(ctx);
return 0;
_
Patches currently in -mm which might be from rppt@xxxxxxxxxxxxxxxxxx are
userfaultfd-non-cooperative-notify-about-unmap-of-destination-during-mremap.patch
userfaultfd_zeropage-return-enospc-in-case-mm-has-gone.patch
userfaultfd-non-cooperative-flush-event_wqh-at-release-time.patch
shmem-shmem_charge-verify-max_block-is-not-exceeded-before-inode-update.patch
shmem-introduce-shmem_inode_acct_block.patch
userfaultfd-shmem-add-shmem_mfill_zeropage_pte-for-userfaultfd-support.patch
userfaultfd-mcopy_atomic-introduce-mfill_atomic_pte-helper.patch
userfaultfd-shmem-wire-up-shmem_mfill_zeropage_pte.patch
userfaultfd-report-uffdio_zeropage-as-available-for-shmem-vmas.patch
userfaultfd-selftest-enable-testing-of-uffdio_zeropage-for-shmem.patch