[CRIU] [PATCH] restore: die if init fails in --restore-detached mode

[Andrew Vagin]

On Wed, Aug 27, 2014 at 09:05:18PM +0000, Tycho Andersen wrote:
> When in --restore-detached (i.e. root_as_sibling) mode, we ptrace(PTRACE_SEIZE)
> the root task to receive its SIGCHLD in case one of its child tasks dies.
> However, we don't receive a SIGCHLD if the root task itself dies, so we must
> explicitly abort.

Acked-by: Andrew Vagin <avagin at parallels.com>
> 
> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> ---
>  cr-restore.c | 44 ++++++++++++++++++++++++--------------------
>  1 file changed, 24 insertions(+), 20 deletions(-)
> 
> diff --git a/cr-restore.c b/cr-restore.c
> index bb29ab5..7bb5cef 100644
> --- a/cr-restore.c
> +++ b/cr-restore.c
> @@ -1365,12 +1365,12 @@ static int restore_task_with_children(void *_arg)
>  		/* Determine PID in CRIU's namespace */
>  		fd = get_service_fd(CR_PROC_FD_OFF);
>  		if (fd < 0)
> -			exit(1);
> +			goto err;
>  
>  		ret = readlinkat(fd, "self", buf, sizeof(buf) - 1);
>  		if (ret < 0) {
>  			pr_perror("Unable to read the /proc/self link");
> -			exit(1);
> +			goto err;
>  		}
>  		buf[ret] = '\0';
>  
> @@ -1385,26 +1385,26 @@ static int restore_task_with_children(void *_arg)
>  	if (current->state != TASK_HELPER) {
>  		ret = clone_service_fd(current->rst->service_fd_id);
>  		if (ret)
> -			exit(1);
> +			goto err;
>  	}
>  
>  	pid = getpid();
>  	if (current->pid.virt != pid) {
>  		pr_err("Pid %d do not match expected %d\n", pid, current->pid.virt);
> -		exit(-1);
> +		goto err;
>  	}
>  
>  	ret = log_init_by_pid();
>  	if (ret < 0)
> -		exit(1);
> +		goto err;
>  
>  	/* Restore root task */
>  	if (current->parent == NULL) {
>  		if (restore_finish_stage(CR_STATE_RESTORE_NS) < 0)
> -			exit(1);
> +			goto err;
>  
>  		if (prepare_namespace(current, ca->clone_flags))
> -			exit(1);
> +			goto err_fini_mnt;
>  
>  		/*
>  		 * We need non /proc proc mount for restoring pid and mount
> @@ -1412,22 +1412,22 @@ static int restore_task_with_children(void *_arg)
>  		 * Thus -- mount proc at custom location for any new namespace
>  		 */
>  		if (mount_proc())
> -			goto err;
> +			goto err_fini_mnt;
>  
>  		if (close_old_fds(current))
> -			exit(1);
> +			goto err_fini_mnt;
>  
>  		if (root_prepare_shared())
> -			goto err;
> +			goto err_fini_mnt;
>  	}
>  
>  	if (prepare_mappings(pid))
> -		goto err;
> +		goto err_fini_mnt;
>  
>  	if (!(ca->clone_flags & CLONE_FILES)) {
>  		ret = close_old_fds(current);
>  		if (ret)
> -			exit(1);
> +			goto err_fini_mnt;
>  	}
>  
>  	/*
> @@ -1437,13 +1437,13 @@ static int restore_task_with_children(void *_arg)
>  	 * just have it inherited.
>  	 */
>  	if (prepare_task_cgroup(current) < 0)
> -		return -1;
> +		goto err_fini_mnt;
>  
>  	if (prepare_sigactions() < 0)
> -		return -1;
> +		goto err_fini_mnt;
>  
>  	if (create_children_and_session())
> -		goto err;
> +		goto err_fini_mnt;
>  
>  	/*
>  	 * This must be done after forking to allow child
> @@ -1454,24 +1454,28 @@ static int restore_task_with_children(void *_arg)
>  	close_service_fd(CGROUP_YARD);
>  
>  	if (restore_task_mnt_ns(current))
> -		goto err;
> +		goto err_fini_mnt;
>  
>  	if (unmap_guard_pages())
> -		goto err;
> +		goto err_fini_mnt;
>  
>  	restore_pgid();
>  
>  	if (restore_finish_stage(CR_STATE_FORKING) < 0)
> -		goto err;
> +		goto err_fini_mnt;
>  
>  	if (current->parent == NULL && fini_mnt_ns())
> -		exit (1);
> +		goto err_fini_mnt;
>  
>  	return restore_one_task(current->pid.virt, ca->core);
> -err:
> +
> +err_fini_mnt:
>  	if (current->parent == NULL)
>  		fini_mnt_ns();
>  
> +err:
> +	if (current->parent == NULL)
> +		futex_abort_and_wake(&task_entries->nr_in_progress);
>  	exit(1);
>  }
>  
> -- 
> 1.9.1
> 
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