When nbd_close() is called from a coroutine, the connection_co never gets to run, and thus nbd_teardown_connection() hangs.
This is because aio_co_enter() only puts the connection_co into the main coroutine's wake-up queue, so this main coroutine needs to yield and reschedule itself to let the connection_co run. Signed-off-by: Max Reitz <mre...@redhat.com> --- block/nbd.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index 81edabbf35..b83b6cd43e 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -135,7 +135,17 @@ static void nbd_teardown_connection(BlockDriverState *bs) qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); - BDRV_POLL_WHILE(bs, s->connection_co); + + if (qemu_in_coroutine()) { + /* Let our caller poll and just yield until connection_co is done */ + while (s->connection_co) { + aio_co_schedule(qemu_get_current_aio_context(), + qemu_coroutine_self()); + qemu_coroutine_yield(); + } + } else { + BDRV_POLL_WHILE(bs, s->connection_co); + } nbd_client_detach_aio_context(bs); object_unref(OBJECT(s->sioc)); -- 2.21.0