Mailing List Archive

Initialization must be completed before calling _vdpa_register_device()
since it can connect the device to the vDPA bus, so requests can arrive
after that call.

So for example vdpasim_net_work(), which uses the net->*_stats variables,
can be scheduled before they are initialized.

Let's move _vdpa_register_device() to the end of vdpasim_net_dev_add()
and add a comment to avoid future issues.

Fixes: 0899774cb360 ("vdpa_sim_net: vendor satistics")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---

Notes:
I don't have a reproducer, but I became aware of this problem while
I was changing the buffer allocation.

In the block device, as soon as the device is registered, the driver
sends several requests, and I guess this might happen for the net
device as well.

Thanks,
Stefano

drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index 862f405362de..dfe2ce341803 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -466,16 +466,21 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,

vdpasim_net_setup_config(simdev, config);

- ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
- if (ret)
- goto reg_err;
-
net = sim_to_net(simdev);

u64_stats_init(&net->tx_stats.syncp);
u64_stats_init(&net->rx_stats.syncp);
u64_stats_init(&net->cq_stats.syncp);

+ /*
+ * Initialization must be completed before this call, since it can
+ * connect the device to the vDPA bus, so requests can arrive after
+ * this call.
+ */
+ ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
+ if (ret)
+ goto reg_err;
+
return 0;

reg_err:
--
2.39.2