Stephan Gerhold
2022-Jun-21 11:48 UTC
[PATCH net] virtio_net: fix xdp_rxq_info bug after suspend/resume
The following sequence currently causes a driver bug warning
when using virtio_net:
# ip link set eth0 up
# echo mem > /sys/power/state (or e.g. # rtcwake -s 10 -m mem)
<resume>
# ip link set eth0 down
Missing register, driver bug
WARNING: CPU: 0 PID: 375 at net/core/xdp.c:138 xdp_rxq_info_unreg+0x58/0x60
Call trace:
xdp_rxq_info_unreg+0x58/0x60
virtnet_close+0x58/0xac
__dev_close_many+0xac/0x140
__dev_change_flags+0xd8/0x210
dev_change_flags+0x24/0x64
do_setlink+0x230/0xdd0
...
This happens because virtnet_freeze() frees the receive_queue
completely (including struct xdp_rxq_info) but does not call
xdp_rxq_info_unreg(). Similarly, virtnet_restore() sets up the
receive_queue again but does not call xdp_rxq_info_reg().
Actually, parts of virtnet_freeze_down() and virtnet_restore_up()
are almost identical to virtnet_close() and virtnet_open(): only
the calls to xdp_rxq_info_(un)reg() are missing. This means that
we can fix this easily and avoid such problems in the future by
just calling virtnet_close()/open() from the freeze/restore handlers.
Aside from adding the missing xdp_rxq_info calls the only difference
is that the refill work is only cancelled if netif_running(). However,
this should not make any functional difference since the refill work
should only be active if the network interface is actually up.
Fixes: 754b8a21a96d ("virtio_net: setup xdp_rxq_info")
Signed-off-by: Stephan Gerhold <stephan.gerhold at kernkonzept.com>
---
drivers/net/virtio_net.c | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index db05b5e930be..969a67970e71 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2768,7 +2768,6 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
static void virtnet_freeze_down(struct virtio_device *vdev)
{
struct virtnet_info *vi = vdev->priv;
- int i;
/* Make sure no work handler is accessing the device */
flush_work(&vi->config_work);
@@ -2776,14 +2775,8 @@ static void virtnet_freeze_down(struct virtio_device
*vdev)
netif_tx_lock_bh(vi->dev);
netif_device_detach(vi->dev);
netif_tx_unlock_bh(vi->dev);
- cancel_delayed_work_sync(&vi->refill);
-
- if (netif_running(vi->dev)) {
- for (i = 0; i < vi->max_queue_pairs; i++) {
- napi_disable(&vi->rq[i].napi);
- virtnet_napi_tx_disable(&vi->sq[i].napi);
- }
- }
+ if (netif_running(vi->dev))
+ virtnet_close(vi->dev);
}
static int init_vqs(struct virtnet_info *vi);
@@ -2791,7 +2784,7 @@ static int init_vqs(struct virtnet_info *vi);
static int virtnet_restore_up(struct virtio_device *vdev)
{
struct virtnet_info *vi = vdev->priv;
- int err, i;
+ int err;
err = init_vqs(vi);
if (err)
@@ -2800,15 +2793,9 @@ static int virtnet_restore_up(struct virtio_device *vdev)
virtio_device_ready(vdev);
if (netif_running(vi->dev)) {
- for (i = 0; i < vi->curr_queue_pairs; i++)
- if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
- schedule_delayed_work(&vi->refill, 0);
-
- for (i = 0; i < vi->max_queue_pairs; i++) {
- virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
- virtnet_napi_tx_enable(vi, vi->sq[i].vq,
- &vi->sq[i].napi);
- }
+ err = virtnet_open(vi->dev);
+ if (err)
+ return err;
}
netif_tx_lock_bh(vi->dev);
--
2.30.2
Jason Wang
2022-Jun-22 08:06 UTC
[PATCH net] virtio_net: fix xdp_rxq_info bug after suspend/resume
On Tue, Jun 21, 2022 at 7:50 PM Stephan Gerhold <stephan.gerhold at kernkonzept.com> wrote:> > The following sequence currently causes a driver bug warning > when using virtio_net: > > # ip link set eth0 up > # echo mem > /sys/power/state (or e.g. # rtcwake -s 10 -m mem) > <resume> > # ip link set eth0 down > > Missing register, driver bug > WARNING: CPU: 0 PID: 375 at net/core/xdp.c:138 xdp_rxq_info_unreg+0x58/0x60 > Call trace: > xdp_rxq_info_unreg+0x58/0x60 > virtnet_close+0x58/0xac > __dev_close_many+0xac/0x140 > __dev_change_flags+0xd8/0x210 > dev_change_flags+0x24/0x64 > do_setlink+0x230/0xdd0 > ... > > This happens because virtnet_freeze() frees the receive_queue > completely (including struct xdp_rxq_info) but does not call > xdp_rxq_info_unreg(). Similarly, virtnet_restore() sets up the > receive_queue again but does not call xdp_rxq_info_reg(). > > Actually, parts of virtnet_freeze_down() and virtnet_restore_up() > are almost identical to virtnet_close() and virtnet_open(): only > the calls to xdp_rxq_info_(un)reg() are missing. This means that > we can fix this easily and avoid such problems in the future by > just calling virtnet_close()/open() from the freeze/restore handlers. > > Aside from adding the missing xdp_rxq_info calls the only difference > is that the refill work is only cancelled if netif_running(). However, > this should not make any functional difference since the refill work > should only be active if the network interface is actually up. > > Fixes: 754b8a21a96d ("virtio_net: setup xdp_rxq_info") > Signed-off-by: Stephan Gerhold <stephan.gerhold at kernkonzept.com>Acked-by: Jason Wang <jasowang at redhat.com>> --- > drivers/net/virtio_net.c | 25 ++++++------------------- > 1 file changed, 6 insertions(+), 19 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index db05b5e930be..969a67970e71 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -2768,7 +2768,6 @@ static const struct ethtool_ops virtnet_ethtool_ops = { > static void virtnet_freeze_down(struct virtio_device *vdev) > { > struct virtnet_info *vi = vdev->priv; > - int i; > > /* Make sure no work handler is accessing the device */ > flush_work(&vi->config_work); > @@ -2776,14 +2775,8 @@ static void virtnet_freeze_down(struct virtio_device *vdev) > netif_tx_lock_bh(vi->dev); > netif_device_detach(vi->dev); > netif_tx_unlock_bh(vi->dev); > - cancel_delayed_work_sync(&vi->refill); > - > - if (netif_running(vi->dev)) { > - for (i = 0; i < vi->max_queue_pairs; i++) { > - napi_disable(&vi->rq[i].napi); > - virtnet_napi_tx_disable(&vi->sq[i].napi); > - } > - } > + if (netif_running(vi->dev)) > + virtnet_close(vi->dev); > } > > static int init_vqs(struct virtnet_info *vi); > @@ -2791,7 +2784,7 @@ static int init_vqs(struct virtnet_info *vi); > static int virtnet_restore_up(struct virtio_device *vdev) > { > struct virtnet_info *vi = vdev->priv; > - int err, i; > + int err; > > err = init_vqs(vi); > if (err) > @@ -2800,15 +2793,9 @@ static int virtnet_restore_up(struct virtio_device *vdev) > virtio_device_ready(vdev); > > if (netif_running(vi->dev)) { > - for (i = 0; i < vi->curr_queue_pairs; i++) > - if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL)) > - schedule_delayed_work(&vi->refill, 0); > - > - for (i = 0; i < vi->max_queue_pairs; i++) { > - virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi); > - virtnet_napi_tx_enable(vi, vi->sq[i].vq, > - &vi->sq[i].napi); > - } > + err = virtnet_open(vi->dev); > + if (err) > + return err; > } > > netif_tx_lock_bh(vi->dev); > -- > 2.30.2 >