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-rw-r--r--kernel/exit.c3
-rw-r--r--kernel/fork.c5
-rw-r--r--kernel/pid.c4
3 files changed, 8 insertions, 4 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 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))