Re: [PATCH v2] usb: gadget: f_ecm: Fix ecm_opts->bound logic in bind path

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Sep 04, 2025 at 02:52:00PM +0800, Kuen-Han Tsai wrote:
> The bound flag in ecm_opts is being set to true even if
> gether_register_netdev() failed.
> 
> Move the assignment of ecm_opts->bound to after the success check to
> ensure the flag only reflects the true state. The race condition on this
> flag is not a concern because the caller, configfs_composite_bind(),
> binds functions sequentially.
> 
> Fixes: d65e6b6e884a ("usb: gadget: f_ecm: Always set current gadget in ecm_bind()")
> Cc: stable@kernel.org
> Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
> ---
>  drivers/usb/gadget/function/f_ecm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/gadget/function/f_ecm.c b/drivers/usb/gadget/function/f_ecm.c
> index 027226325039..9f5ed6f32a62 100644
> --- a/drivers/usb/gadget/function/f_ecm.c
> +++ b/drivers/usb/gadget/function/f_ecm.c
> @@ -690,13 +690,14 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f)
>  
>  	if (!ecm_opts->bound) {
>  		status = gether_register_netdev(ecm_opts->net);
> -		ecm_opts->bound = true;
>  	}
>  
>  	mutex_unlock(&ecm_opts->lock);
>  	if (status)
>  		return status;
>  
> +	ecm_opts->bound = true;
> +
>  	ecm_string_defs[1].s = ecm->ethaddr;
>  
>  	us = usb_gstrings_attach(cdev, ecm_strings,
> -- 
> 2.51.0.338.gd7d06c2dae-goog
> 
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

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