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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
