Re: [PATCH net v2] s390/iucv: Fix vargs handling in iucv_alloc_device()

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

On 8/20/24 10:45, Alexandra Winter wrote:
> iucv_alloc_device() gets a format string and a varying number of
> arguments. This is incorrectly forwarded by calling dev_set_name() with
> the format string and a va_list, while dev_set_name() expects also a
> varying number of arguments.
> 
> Symptoms:
> Corrupted iucv device names, which can result in log messages like:
> sysfs: cannot create duplicate filename '/devices/iucv/hvc_iucv1827699952'
> 
> Fixes: 4452e8ef8c36 ("s390/iucv: Provide iucv_alloc_device() / iucv_release_device()")
> Link: https://bugzilla.suse.com/show_bug.cgi?id=1228425
> Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
> Reviewed-by: Thorsten Winkler <twinkler@linux.ibm.com>
> ---
> Discussion of v1:
> Link: https://lore.kernel.org/all/2024081326-shifter-output-cb8f@gregkh/T/#mf8ae979de8acdc01f7ede0b94af6f2e110eea209

side note: that's nice that you have continued Vasily's series as your
own v2

> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202408091131.ATGn6YSh-lkp@intel.com/
> Vasily Gorbik asked me to send this version via the netdev mailing list.
> ---
>   net/iucv/iucv.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
> index 1e42e13ad24e..2e615641a4e5 100644
> --- a/net/iucv/iucv.c
> +++ b/net/iucv/iucv.c
> @@ -86,13 +86,15 @@ struct device *iucv_alloc_device(const struct attribute_group **attrs,
>   {
>   	struct device *dev;
>   	va_list vargs;
> +	char buf[20];
>   	int rc;
>   
>   	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
>   	if (!dev)
>   		goto out_error;
>   	va_start(vargs, fmt);
> -	rc = dev_set_name(dev, fmt, vargs);
> +	vsnprintf(buf, sizeof(buf), fmt, vargs);
> +	rc = dev_set_name(dev, buf);

would be good to pass "%s" as fmt to dev_set_name()

otherwise this patch is good for me, so please add my:
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>

>   	va_end(vargs);
>   	if (rc)
>   		goto out_error;