On Monday, November 28, 2022 3:10:02 AM CET Li Zetao wrote:
> When doing the following test steps, an error was found:
> step 1: modprobe 9pnet_virtio succeeded
> # modprobe 9pnet_virtio <-- OK
>
> step 2: fault injection in sysfs_create_file()
> # modprobe -r 9pnet_virtio <-- OK
> # ...
> FAULT_INJECTION: forcing a failure.
> name failslab, interval 1, probability 0, space 0, times 0
> CPU: 0 PID: 3790 Comm: modprobe Tainted: G W
> 6.1.0-rc6-00285-g6a1e40c4b995-dirty #108
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
> Call Trace:
> <TASK>
> ...
> should_failslab+0xa/0x20
> ...
> sysfs_create_file_ns+0x130/0x1d0
> p9_virtio_probe+0x662/0xb30 [9pnet_virtio]
> virtio_dev_probe+0x608/0xae0
> ...
> </TASK>
> 9pnet_virtio: probe of virtio3 failed with error -12
>
> step 3: modprobe virtio_net failed
> # modprobe 9pnet_virtio <-- failed
> 9pnet_virtio: probe of virtio3 failed with error -2
>
> The root cause of the problem is that the virtqueues are not
> stopped on the error handling path when sysfs_create_file()
> fails in p9_virtio_probe(), resulting in an error "-ENOENT"
> returned in the next modprobe call in setup_vq().
>
> virtio_pci_modern_device uses virtqueues to send or
> receive message, and "queue_enable" records whether the
> queues are available. In vp_modern_find_vqs(), all queues
> will be selected and activated, but once queues are enabled
> there is no way to go back except reset.
>
> Fix it by reset virtio device on error handling path. After
> virtio_find_single_vq() succeeded, all virtqueues should be
> stopped on error handling path.
>
> Fixes: 1fcf0512c9c8 ("virtio_pci: modern driver")
> Signed-off-by: Li Zetao <lizetao1@xxxxxxxxxx>
> ---
As others said, comment should probably be adjusted, apart from that:
Reviewed-by: Christian Schoenebeck <linux_oss@xxxxxxxxxxxxx>
> net/9p/trans_virtio.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
> index e757f0601304..39933187284b 100644
> --- a/net/9p/trans_virtio.c
> +++ b/net/9p/trans_virtio.c
> @@ -668,6 +668,7 @@ static int p9_virtio_probe(struct virtio_device *vdev)
> out_free_tag:
> kfree(tag);
> out_free_vq:
> + virtio_reset_device(vdev);
> vdev->config->del_vqs(vdev);
> out_free_chan:
> kfree(chan);
>
