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 09:33:32AM +0200, Greg KH wrote:
> 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,
> 
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