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 65113a304518..874670450996 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2423,7 +2423,10 @@ __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..386e51fcebb3 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 */
@@ -219,7 +219,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *arg_set_tid,
 			 * Also fail if a PID != 1 is requested and
 			 * no PID 1 exists.
 			 */
-			if (tid != 1 && !tmp->child_reaper)
+			if (tid != 1 && !READ_ONCE(tmp->child_reaper))
 				goto out_abort;
 			retval = -EPERM;
 			if (!checkpoint_restore_ns_capable(tmp->user_ns))