Re: [PATCH 1/5] sched: convert sighand_struct.count to refcount_t

[Oleg Nesterov <oleg@xxxxxxxxxx>]

On 01/18, Elena Reshetova wrote:
>
> --- a/fs/proc/task_nommu.c
> +++ b/fs/proc/task_nommu.c
> @@ -64,7 +64,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
>  	else
>  		bytes += kobjsize(current->files);
>  
> -	if (current->sighand && atomic_read(&current->sighand->count) > 1)
> +	if (current->sighand && refcount_read(&current->sighand->count) > 1)
>  		sbytes += kobjsize(current->sighand);
>  	else
>  		bytes += kobjsize(current->sighand);

I fail to understand this code with or without the patch... I do not see
how is it possible to hit ->sighand == NULL or sighand->count == 0 in
proc_pid_status() paths.

Nevermind, this is off-topic.

Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>