Re: [PATCH] usb: gadget: f_uac1_legacy: fix inverted NULL check after kstrndup()

[Frank Li]

On Wed, Jul 08, 2026 at 05:05:03PM +0200, Greg KH wrote:
> On Thu, Jun 25, 2026 at 07:31:54PM +0800, Xu Yang wrote:
> > From: Xu Yang <xu.yang_2@xxxxxxx>
> >
> > kstrndup() returns NULL on allocation failure. The condition was
> > checking 'if (tmp)' to detect failure, but this is inverted — it
> > would treat a successful allocation as an error and return -ENOMEM
> > while leaking the string, and proceed with a NULL pointer on failure.
> >
> > Fix by changing the condition to 'if (!tmp)'.
> >
> > Fixes: 0854611a19ae ("usb: gadget: f_uac1: add configfs support")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Assisted-by: Claude:claude-sonnet-4-6
> > Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
> > ---
> >  drivers/usb/gadget/function/f_uac1_legacy.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
> > index 5d201a2e30e7..e9f2632ce785 100644
> > --- a/drivers/usb/gadget/function/f_uac1_legacy.c
> > +++ b/drivers/usb/gadget/function/f_uac1_legacy.c
> > @@ -914,7 +914,7 @@ static ssize_t f_uac1_opts_##name##_store(struct config_item *item,	\
> >  		goto end;						\
> >  									\
> >  	tmp = kstrndup(page, len, GFP_KERNEL);				\
> > -	if (tmp) {							\
> > +	if (!tmp) {							\
> >  		ret = -ENOMEM;						\
> >  		goto end;						\
> >  	}								\
> > --
> > 2.34.1
> >
> >
>
> So this has never worked?  How has no one ever noticed that in the
> decade this has been in the kernel?  Does that mean that no one uses
> this file/driver and we can just remove it?

I think just no one use sys interface to change name.

Frank

>
> thanks,
>
> greg k-h
>