[CRIU] [PATCH v2] seize: Wait the freezer to complete before processing tags

[Pavel Emelyanov]

> @@ -291,45 +304,38 @@ static int freeze_processes(void)
>  			close(fd);
>  			return -1;
>  		}
> -	}
>  
> -	/*
> -	 * There is not way to wait a specified state, so we need to poll the
> -	 * freezer.state.
> -	 * Here is one extra attempt to check that everything are frozen.
> -	 */
> -	for (i = 0; i <= nr_attempts; i++) {

Which tree is it against? There's timeout handling declarations here.

> -		if (seize_cgroup_tree(opts.freeze_cgroup, state) < 0)
> -			goto err;
> +		/*
> +		 * Wait the freezer to complete before
> +		 * processing tasks. They might be exiting
> +		 * before freezing complete so we should
> +		 * not read @tasks pids while freezer in
> +		 * transition stage.
> +		 */
> +		for (i = 0; i <= nr_attempts; i++) {
> +			state = get_freezer_state(fd);
> +			if (!state) {
> +				close(fd);
> +				return -1;
> +			}
>  
> -		if (state == frozen)
> -			break;
> +			if (state == frozen)
> +				break;
> +			if (alarm_timeouted())
> +				goto err;
> +			nanosleep(&req, NULL);
> +		}
>  
> -		state = get_freezer_state(fd);
> -		if (!state)
> +		if (i > nr_attempts) {
> +			pr_err("Unable to freeze cgroup %s\n", opts.freeze_cgroup);
>  			goto err;
> -
> -		if (state == frozen) {
> -			/*
> -			 * Enumerate all tasks one more time to collect all new
> -			 * tasks, which can be born while the cgroup is being frozen.
> -			 */
> -
> -			continue;
>  		}
>  
> -		if (alarm_timeouted())
> -			goto err;
> -		nanosleep(&req, NULL);
> +		pr_debug("freezing processes: %lu attempts done\n", i);
>  	}
>  
> -	if (i > nr_attempts) {
> -		pr_err("Unable to freeze cgroup %s\n", opts.freeze_cgroup);
> -		goto err;
> -	}
> +	exit_code = seize_cgroup_tree(opts.freeze_cgroup, state);
>  
> -	pr_debug("freezing processes: %lu attempts done\n", i);
> -	exit_code = 0;
>  err:
>  	if (exit_code == 0 || freezer_thawed) {
>  		lseek(fd, 0, SEEK_SET);
>