Re: [PATCH] virtio_net: Abort driver initialization if device fails

["Michael S. Tsirkin" <mst@redhat.com>]

On Sun, Aug 28, 2022 at 06:48:20PM +0300, Eli Cohen wrote:
> Read the status bit after virtio_device_ready() to check if device
> initialization was successful. If it was not, abort driver
> initialization to avoid further attempts to access device resources.
> 
> Abort is required per virtio spec v1.1
> 
> 3.1.1
> ...
> If any of these steps go irrecoverably wrong, the driver SHOULD set the
> FAILED status bit to indicate that it has given up on the device (it can
> reset the device later to restart if desired). The driver MUST NOT
> continue initialization in that case.

I don't see a requirement to read the status bit though
which is what the patch does.

> This fixes an issue that was discovered when mlx5_vdpa initialization
> failed due to firmware error

A bit more detail would be nice. which function failed exactly?

> and subsequent attempts to send control VQ
> commands failed with a call trace:
> 
>  watchdog: BUG: soft lockup - CPU#62 stuck for 26s! [systemd-udevd:2610]
>  Modules linked in: virtio_net(+) net_failover failover virtio_vdpa mlx5_vdpa vringh vhost_iotlb vdpa mlx5_ib ib_uverbs ib_core mlx5_core mlxfw psample tls pci>
>   drm ghash_clmulni_intel serio_raw usb_storage scsi_transport_sas hpwdt wmi target_core_mod [last unloaded: ib_core]
>  CPU: 62 PID: 2610 Comm: systemd-udevd Tainted: G I        6.0.0-rc2+ #7
>  Hardware name: HPE ProLiant DL380 Gen10/ProLiant DL380 Gen10, BIOS U30 04/08/2020
>  RIP: 0010:virtnet_send_command+0xfa/0x140 [virtio_net]
>  Code: ec f0 80 e0 85 c0 0f 88 0c 68 00 00 48 8b 7b 08 e8 9b d6 80 e0 84 c0 75 11 eb 43 48 8b 7b 08 e8 7c c3 80 e0 84 c0 75 15 f3 90 <48> 8b 7b 08 48 8d 74 24 >
>  RSP: 0018:ffffb6fba2037b78 EFLAGS: 00000246
>  RAX: 0000000000000000 RBX: ffff99c6043a99c0 RCX: 0000000000000000
>  RDX: 0000000000000000 RSI: ffffb6fba2037b7c RDI: ffff99c6042c6500
>  RBP: ffffb6fba2037bc0 R08: 0000000000000001 R09: 0000000000000000
>  R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000002
>  R13: 0000000000000004 R14: 0000000000000000 R15: ffff99f634258400
>  FS:  00007f5894eefb40(0000) GS:ffff99dd9fb80000(0000) knlGS:0000000000000000
>  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  CR2: 000055acd4a80000 CR3: 00000018605a4002 CR4: 00000000007706e0
>  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>  PKRU: 55555554
>  Call Trace:
>   <TASK>
>   _virtnet_set_queues+0x7f/0xc0 [virtio_net]
>   virtnet_probe+0x989/0xae0 [virtio_net]
>   virtio_dev_probe+0x1ab/0x260
>   really_probe+0xde/0x390
>   ? pm_runtime_barrier+0x50/0x90
>   __driver_probe_device+0x78/0x180
>   driver_probe_device+0x1e/0x90
>   __driver_attach+0xc4/0x1e0
>   ? __device_attach_driver+0xe0/0xe0
>   ? __device_attach_driver+0xe0/0xe0
>   bus_for_each_dev+0x61/0x90
>   bus_add_driver+0x1a9/0x200
>   driver_register+0x8f/0xf0
>   ? 0xffffffffc0fdb000
>   virtio_net_driver_init+0x70/0x1000 [virtio_net]
>   do_one_initcall+0x41/0x210
>   ? kmem_cache_alloc_trace+0x16d/0x2c0
>   do_init_module+0x4c/0x1f0
>   __do_sys_finit_module+0x9f/0x100
>   do_syscall_64+0x38/0x90
>   entry_SYSCALL_64_after_hwframe+0x63/0xcd
>  RIP: 0033:0x7f589510aecd
>  Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 >
>  RSP: 002b:00007ffde61fb398 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
>  RAX: ffffffffffffffda RBX: 000055acd48ac950 RCX: 00007f589510aecd
>  RDX: 0000000000000000 RSI: 00007f589584332c RDI: 0000000000000012
>  RBP: 0000000000020000 R08: 0000000000000000 R09: 0000000000000002
>  R10: 0000000000000012 R11: 0000000000000246 R12: 00007f589584332c
>  R13: 000055acd4867c70 R14: 0000000000000007 R15: 000055acd48980a0
>   </TASK>
> 
> Fixes: commit 4baf1e33d084 ("virtio_net: enable VQs early")
> Signed-off-by: Eli Cohen <elic@nvidia.com>
> ---
>  drivers/net/virtio_net.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 9cce7dec7366..4698d9a28a6f 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3900,6 +3900,11 @@ static int virtnet_probe(struct virtio_device *vdev)
>  	}
>  
>  	virtio_device_ready(vdev);
> +	if (vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_FAILED) {
> +		err = -EINVAL;
> +		rtnl_unlock();
> +		goto unregister_ndev;
> +	}
>  
>  	rtnl_unlock();
>  

I don't get it. What set the failed status?


> @@ -3934,7 +3939,7 @@ static int virtnet_probe(struct virtio_device *vdev)
>  
>  free_unregister_netdev:
>  	virtio_reset_device(vdev);
> -
> +unregister_ndev:
>  	unregister_netdev(dev);
>  free_failover:
>  	net_failover_destroy(vi->failover);
> -- 
> 2.35.1

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