Commit 5a18b64e authored Aug 02, 2017 by Mike Rapoport Committed by Linus Torvalds Aug 02, 2017

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@linux.vnet.ibm.com


Fixes: 9cd75c3c ("userfaultfd: non-cooperative: add ability to report
non-PF events from uffd descriptor")
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent ade9f91b

fs/userfaultfd.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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;

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