[PATCH 3.16.y-ckt 064/104] net/xen-netfront: only napi_synchronize() if running
From: Luis Henriques <hidden>
Date: 2015-10-26 13:59:16
Also in:
lkml
Subsystem:
networking drivers, the rest, xen hypervisor interface · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Juergen Gross, Stefano Stabellini
3.16.7-ckt19 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Chas Williams <3chas3@gmail.com> commit 274b045509175db0405c784be85e8cce116e6f7d upstream. 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] [<ffffffff81796927>] schedule+0x37/0x90 [ 392.298553] [<ffffffff8179985b>] schedule_timeout+0x14b/0x280 [ 392.306421] [<ffffffff810f91b9>] ? irq_free_descs+0x69/0x80 [ 392.314006] [<ffffffff811084d0>] ? internal_add_timer+0xb0/0xb0 [ 392.322125] [<ffffffff81109d07>] msleep+0x37/0x50 [ 392.329037] [<ffffffffa00ec79a>] xennet_disconnect_backend.isra.24+0xda/0x390 [xen_netfront] [ 392.339658] [<ffffffffa00ecadc>] xennet_remove+0x2c/0x80 [xen_netfront] [ 392.348516] [<ffffffff81481c69>] xenbus_dev_remove+0x59/0xc0 [ 392.356257] [<ffffffff814e7217>] __device_release_driver+0x87/0x120 [ 392.364645] [<ffffffff814e7cf8>] driver_detach+0xb8/0xc0 [ 392.371989] [<ffffffff814e6e69>] bus_remove_driver+0x59/0xe0 [ 392.379883] [<ffffffff814e84f0>] driver_unregister+0x30/0x70 [ 392.387495] [<ffffffff814814b2>] xenbus_unregister_driver+0x12/0x20 [ 392.395908] [<ffffffffa00ed89b>] netif_exit+0x10/0x775 [xen_netfront] [ 392.404877] [<ffffffff81124e08>] SyS_delete_module+0x1d8/0x230 [ 392.412804] [<ffffffff8179a8ee>] system_call_fastpath+0x12/0x71 Signed-off-by: Chas Williams <3chas3@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Cc: Kamata, Munehisa <redacted> Signed-off-by: Luis Henriques <redacted> --- 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 0838a2db5570..9d3bdea182cd 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c@@ -1449,7 +1449,8 @@ 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); /* End access and free the pages */ xennet_end_access(queue->tx_ring_ref, queue->tx.sring);