[Devel] [PATCH vz10 16/24] drivers/base/cpu: fix cpu/offline content inside a ve

[Pavel Tikhomirov]

Reviewed-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

On 7/6/26 12:59, Konstantin Khorenko wrote:
> print_cpus_offline()'s non-super-ve early return passed len (declared
> 0 at that point, used later only as the sysfs_emit_at() accumulator)
> as snprintf()'s size argument, so nothing was ever written to buf.
> Since sysfs zeroes the page before calling show(), reading
> /sys/devices/system/cpu/offline from inside a ve returned a single
> NUL byte instead of the intended empty line ("\n").
> 
> Fixes: 13cc6987a961 ("ve/cpu: handle sysfs attributes for CTs")
> Feature: sysfs: per-CT entries visibility and permissions configuration
> https://virtuozzo.atlassian.net/browse/VSTOR-137234
> Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
> ---
>  drivers/base/cpu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index 1e992254b12c..b7ddc8346603 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -263,7 +263,7 @@ static ssize_t print_cpus_offline(struct device *dev,
>  	cpumask_var_t offline;
>  
>  	if (!ve_is_super(get_exec_env()))
> -		return snprintf(buf, len, "\n");
> +		return sysfs_emit(buf, "\n");
>  
>  	/* display offline cpus < nr_cpu_ids */
>  	if (!alloc_cpumask_var(&offline, GFP_KERNEL))

-- 
Best regards, Pavel Tikhomirov
Senior Software Developer, Virtuozzo.