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SubjectRe: [PATCH 2/4] virtio-mem: Fix probe failed when modprobe virtio_mem
On 28.11.22 03:10, Li Zetao wrote:
> When doing the following test steps, an error was found:
> step 1: modprobe virtio_mem succeeded
> # modprobe virtio_mem <-- OK
>
> step 2: fault injection in virtio_mem_init()
> # modprobe -r virtio_mem <-- OK
> # ...
> CPU: 0 PID: 1837 Comm: modprobe Not tainted
> 6.1.0-rc6-00285-g6a1e40c4b995-dirty
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
> Call Trace:
> <TASK>
> should_fail.cold+0x5/0x1f
> ...
> virtio_mem_init_hotplug+0x9ae/0xe57 [virtio_mem]
> virtio_mem_init.cold+0x327/0x339 [virtio_mem]
> virtio_mem_probe+0x48e/0x910 [virtio_mem]
> virtio_dev_probe+0x608/0xae0
> ...
> </TASK>
> virtio_mem virtio4: could not reserve device region
> virtio_mem: probe of virtio4 failed with error -16
>
> step 3: modprobe virtio_net failed

virtio_net ?

> # modprobe virtio_mem <-- failed
> virtio_mem: probe of virtio4 failed with error -16
>
> The root cause of the problem is that the virtqueues are not
> stopped on the error handling path when virtio_mem_init()
> fails in virtio_mem_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_mem_init_vq() succeeded, all virtqueues should be
> stopped on error handling path.
>
> Fixes: 1fcf0512c9c8 ("virtio_pci: modern driver")

That commit is from 2014. virtio-mem was merged in 2020

Fixes: 5f1f79bbc9e2 ("virtio-mem: Paravirtualized memory hotplug")

> Signed-off-by: Li Zetao <lizetao1@huawei.com>
> ---
> drivers/virtio/virtio_mem.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
> index 0c2892ec6817..c7f09c2ce982 100644
> --- a/drivers/virtio/virtio_mem.c
> +++ b/drivers/virtio/virtio_mem.c
> @@ -2793,6 +2793,7 @@ static int virtio_mem_probe(struct virtio_device *vdev)
>
> return 0;
> out_del_vq:
> + virtio_reset_device(vdev);
> vdev->config->del_vqs(vdev);
> out_free_vm:
> kfree(vm);


Apart from that

Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb

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