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 <sgarz...@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

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Reply via email to