diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exit.c | 3 | ||||
| -rw-r--r-- | kernel/fork.c | 5 | ||||
| -rw-r--r-- | kernel/pid.c | 19 | ||||
| -rw-r--r-- | kernel/pid_namespace.c | 9 | ||||
| -rw-r--r-- | kernel/signal.c | 5 |
5 files changed, 20 insertions, 21 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index ede3117fa7d4..31b714c3a791 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -608,7 +608,8 @@ static struct task_struct *find_child_reaper(struct task_struct *father, reaper = find_alive_thread(father); if (reaper) { - pid_ns->child_reaper = reaper; + ASSERT_EXCLUSIVE_WRITER(pid_ns->child_reaper); + WRITE_ONCE(pid_ns->child_reaper, reaper); return reaper; } diff --git a/kernel/fork.c b/kernel/fork.c index 9c194fc58736..8c61c8dd4372 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2469,7 +2469,10 @@ __latent_entropy struct task_struct *copy_process( init_task_pid(p, PIDTYPE_SID, task_session(current)); if (is_child_reaper(pid)) { - ns_of_pid(pid)->child_reaper = p; + struct pid_namespace *ns = ns_of_pid(pid); + + ASSERT_EXCLUSIVE_WRITER(ns->child_reaper); + WRITE_ONCE(ns->child_reaper, p); p->signal->flags |= SIGNAL_UNKILLABLE; } p->signal->shared_pending.signal = delayed.signal; diff --git a/kernel/pid.c b/kernel/pid.c index 3b96571d0fe6..677c84e319dd 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -128,7 +128,7 @@ void free_pid(struct pid *pid) * is the reaper wake up the reaper. The reaper * may be sleeping in zap_pid_ns_processes(). */ - wake_up_process(ns->child_reaper); + wake_up_process(READ_ONCE(ns->child_reaper)); break; case PIDNS_ADDING: /* Handle a fork failure of the first process */ @@ -215,12 +215,6 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, retval = -EINVAL; if (tid < 1 || tid >= pid_max[ns->level - i]) goto out_abort; - /* - * Also fail if a PID != 1 is requested and - * no PID 1 exists. - */ - if (tid != 1 && !tmp->child_reaper) - goto out_abort; retval = -EPERM; if (!checkpoint_restore_ns_capable(tmp->user_ns)) goto out_abort; @@ -296,9 +290,18 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid, pid->numbers[i].nr = nr; pid->numbers[i].ns = tmp; - tmp = tmp->parent; i--; retried_preload = false; + + /* + * PID 1 (init) must be created first. + */ + if (!READ_ONCE(tmp->child_reaper) && nr != 1) { + retval = -EINVAL; + goto out_free; + } + + tmp = tmp->parent; } /* diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index e48f5de41361..d36afc58ee1d 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -369,15 +369,6 @@ static struct ns_common *pidns_for_children_get(struct task_struct *task) } task_unlock(task); - if (ns) { - read_lock(&tasklist_lock); - if (!ns->child_reaper) { - put_pid_ns(ns); - ns = NULL; - } - read_unlock(&tasklist_lock); - } - return ns ? &ns->ns : NULL; } diff --git a/kernel/signal.c b/kernel/signal.c index e61f39fa8c8a..21d881b95ffb 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2818,8 +2818,9 @@ bool get_signal(struct ksignal *ksig) /* * Do this once, we can't return to user-mode if freezing() == T. - * do_signal_stop() and ptrace_stop() do freezable_schedule() and - * thus do not need another check after return. + * do_signal_stop() and ptrace_stop() set TASK_STOPPED/TASK_TRACED + * and the freezer handles those states via TASK_FROZEN, thus they + * do not need another check after return. */ try_to_freeze(); |