Re: [PATCH] uprobes: Fix race in uprobe_free_utask

[Oleg Nesterov <oleg@xxxxxxxxxx>]

On 01/09, Jiri Olsa wrote:
>
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1915,6 +1915,7 @@ void uprobe_free_utask(struct task_struct *t)
>  	if (!utask)
>  		return;
>
> +	t->utask = NULL;
>  	WARN_ON_ONCE(utask->active_uprobe || utask->xol_vaddr);
>
>  	timer_delete_sync(&utask->ri_timer);
> @@ -1924,7 +1925,6 @@ void uprobe_free_utask(struct task_struct *t)
>  		ri = free_ret_instance(ri, true /* cleanup_hprobe */);
>
>  	kfree(utask);
> -	t->utask = NULL;

Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>