From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Charles (Chas) Williams" <3chas3@gmail.com> Subject: [PATCH net-next] net/xen-netfront: only napi_synchronize() if running Date: Thu, 27 Aug 2015 12:28:46 -0400 Message-ID: <1440692926.2546.31.camel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net To: netdev@vger.kernel.org Return-path: Received: from mail-yk0-f182.google.com ([209.85.160.182]:36708 "EHLO mail-yk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752648AbbH0Q2s (ORCPT ); Thu, 27 Aug 2015 12:28:48 -0400 Received: by ykfw73 with SMTP id w73so25618474ykf.3 for ; Thu, 27 Aug 2015 09:28:47 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: From: Chas Williams <3chas3@gmail.com> If an interface isn't running napi_synchronize() will hang forever. [ 392.248403] rmmod R running task 0 359 343 0x00000000 [ 392.257671] ffff88003760fc88 ffff880037193b40 ffff880037193160 ffff88003760fc88 [ 392.267644] ffff880037610000 ffff88003760fcd8 0000000100014c22 ffffffff81f75c40 [ 392.277524] 0000000000bc7010 ffff88003760fca8 ffffffff81796927 ffffffff81f75c40 [ 392.287323] Call Trace: [ 392.291599] [] schedule+0x37/0x90 [ 392.298553] [] schedule_timeout+0x14b/0x280 [ 392.306421] [] ? irq_free_descs+0x69/0x80 [ 392.314006] [] ? internal_add_timer+0xb0/0xb0 [ 392.322125] [] msleep+0x37/0x50 [ 392.329037] [] xennet_disconnect_backend.isra.24+0xda/0x390 [xen_netfront] [ 392.339658] [] xennet_remove+0x2c/0x80 [xen_netfront] [ 392.348516] [] xenbus_dev_remove+0x59/0xc0 [ 392.356257] [] __device_release_driver+0x87/0x120 [ 392.364645] [] driver_detach+0xb8/0xc0 [ 392.371989] [] bus_remove_driver+0x59/0xe0 [ 392.379883] [] driver_unregister+0x30/0x70 [ 392.387495] [] xenbus_unregister_driver+0x12/0x20 [ 392.395908] [] netif_exit+0x10/0x775 [xen_netfront] [ 392.404877] [] SyS_delete_module+0x1d8/0x230 [ 392.412804] [] system_call_fastpath+0x12/0x71 Signed-off-by: Chas Williams <3chas3@gmail.com> --- drivers/net/xen-netfront.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index f948c46..5ff0cfd 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1348,7 +1348,8 @@ static void xennet_disconnect_backend(struct netfront_info *info) queue->tx_evtchn = queue->rx_evtchn = 0; queue->tx_irq = queue->rx_irq = 0; - napi_synchronize(&queue->napi); + if (netif_running(info->netdev)) + napi_synchronize(&queue->napi); xennet_release_tx_bufs(queue); xennet_release_rx_bufs(queue); -- 2.1.0