From: Alok Tiwari <[email protected]> Sent: Saturday, September 13, 2025 
12:25 PM
> 
> The target_cpu_store() function parses the target CPU from the sysfs
> buffer using sscanf(). The format string currently uses "%uu", which
> is invalid and causes incorrect parsing.

The %uu format string definitely looks invalid, but I'm not seeing
incorrect parsing.  For example, this command works:

# echo 5 >/sys/bus/vmbus/devices/<uuid>/channels/<nn>/cpu

and the target cpu is indeed changed to "5".  A two-digit value also
works:

# echo 14 >/sys/bus/vmbus/devices/<uuid>/channels/<nn>/cpu

What are the details of the incorrect parsing that you are seeing?

Michael

> 
> Fix it by using "%u" to correctly read the value.
> 
> This only fixes the parsing format.
> 
> Signed-off-by: Alok Tiwari <[email protected]>
> ---
>  drivers/hv/vmbus_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 8b58306cb140..fbab9f2d7fa6 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1742,7 +1742,7 @@ static ssize_t target_cpu_store(struct vmbus_channel
> *channel,
>       u32 target_cpu;
>       ssize_t ret;
> 
> -     if (sscanf(buf, "%uu", &target_cpu) != 1)
> +     if (sscanf(buf, "%u", &target_cpu) != 1)
>               return -EIO;
> 
>       cpus_read_lock();
> --
> 2.50.1
> 


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