Re: [PATCH 3/6] Drivers: hv: initialize partition table before device registration

[Wei Liu <wei.liu@kernel.org>]

On Wed, Oct 28, 2026 at 12:48:23PM +0800, Jiale Yao wrote:
> misc_register() exposes /dev/mshv before the partition hash table and
> its lock are initialized. A partition ioctl racing module initialization
> can therefore access the table through an uninitialized spinlock.
> 
> Initialize the partition table and lock before registering the misc
> device.
> 
> Fixes: 621191d709b1 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jiale Yao <yaojiale02@163.com>

If such races are really a problem, shouldn't the msic_register call be
the last in the function?

Wei

> ---
>  drivers/hv/mshv_root_main.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
> index cc2cfce2aefd..ce26320035b6 100644
> --- a/drivers/hv/mshv_root_main.c
> +++ b/drivers/hv/mshv_root_main.c
> @@ -2369,6 +2369,9 @@ static int __init mshv_parent_partition_init(void)
>  	if (hv_get_hypervisor_version(&version_info))
>  		return -ENODEV;
>  
> +	spin_lock_init(&mshv_root.pt_ht_lock);
> +	hash_init(mshv_root.pt_htable);
> +
>  	ret = misc_register(&mshv_dev);
>  	if (ret)
>  		return ret;
> @@ -2407,9 +2410,6 @@ static int __init mshv_parent_partition_init(void)
>  	if (ret)
>  		goto exit_debugfs;
>  
> -	spin_lock_init(&mshv_root.pt_ht_lock);
> -	hash_init(mshv_root.pt_htable);
> -
>  	hv_setup_mshv_handler(mshv_isr);
>  
>  	return 0;
> -- 
> 2.34.1
>