Re: [PATCH net 1/2] vsock: fix child netns mode initialization

[Bobby Eshleman <bobbyeshleman@gmail.com>]

On Thu, Feb 12, 2026 at 09:59:15PM +0100, Stefano Garzarella wrote:
> From: Stefano Garzarella <sgarzare@redhat.com>
> 
> When a new network namespace is created, vsock_net_init() correctly
> initializes the namespace's mode by reading the parent's `child_ns_mode`
> via vsock_net_child_mode(). However, the `child_ns_mode` of the new
> namespace was always hardcoded to VSOCK_NET_MODE_GLOBAL, regardless of
> its own mode.
> 
> This means that if a parent namespace has `child_ns_mode` set to "local",
> the child namespace correctly gets mode "local", but its `child_ns_mode`
> is reset to "global". As a result, further nested namespaces will
> incorrectly get mode "global" instead of inheriting "local", breaking
> the expected propagation of the mode through nested namespaces.
> 
> Fix this by initializing `child_ns_mode` to the namespace's own mode,
> so the setting propagates correctly through all levels of nesting.
> 
> Fixes: eafb64f40ca4 ("vsock: add netns to vsock core")
> Cc: bobbyeshleman@meta.com
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>  net/vmw_vsock/af_vsock.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index 20ad2b2dc17b..3b629b4a0359 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -91,7 +91,8 @@
>   *   - /proc/sys/net/vsock/ns_mode (read-only) reports the current namespace's
>   *     mode, which is set at namespace creation and immutable thereafter.
>   *   - /proc/sys/net/vsock/child_ns_mode (writable) controls what mode future
> - *     child namespaces will inherit when created. The default is "global".
> + *     child namespaces will inherit when created. The initial value matches
> + *     the namespace's own ns_mode.
>   *
>   *   Changing child_ns_mode only affects newly created namespaces, not the
>   *   current namespace or existing children. At namespace creation, ns_mode
> @@ -2912,7 +2913,7 @@ static void vsock_net_init(struct net *net)
>  	else
>  		net->vsock.mode = vsock_net_child_mode(current->nsproxy->net_ns);
>  
> -	net->vsock.child_ns_mode = VSOCK_NET_MODE_GLOBAL;
> +	net->vsock.child_ns_mode = net->vsock.mode;
>  }
>  
>  static __net_init int vsock_sysctl_init_net(struct net *net)
> -- 
> 2.53.0
> 

LGTM.

Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>