diff options
| -rw-r--r-- | kernel/fork.c | 10 | ||||
| -rw-r--r-- | kernel/sys.c | 22 |
2 files changed, 29 insertions, 3 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 135b7a49ad59..c814e590cf76 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1367,9 +1367,6 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) sig->oom_score_adj = current->signal->oom_score_adj; sig->oom_score_adj_min = current->signal->oom_score_adj_min; - sig->has_child_subreaper = current->signal->has_child_subreaper || - current->signal->is_child_subreaper; - mutex_init(&sig->cred_guard_mutex); return 0; @@ -1800,6 +1797,13 @@ static __latent_entropy struct task_struct *copy_process( p->signal->leader_pid = pid; p->signal->tty = tty_kref_get(current->signal->tty); + /* + * Inherit has_child_subreaper flag under the same + * tasklist_lock with adding child to the process tree + * for propagate_has_child_subreaper optimization. + */ + p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || + p->real_parent->signal->is_child_subreaper; list_add_tail(&p->sibling, &p->real_parent->children); list_add_tail_rcu(&p->tasks, &init_task.tasks); attach_pid(p, PIDTYPE_PGID); diff --git a/kernel/sys.c b/kernel/sys.c index 842914ef7de4..0e4d566a6f16 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2063,6 +2063,24 @@ static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr) } #endif +static int propagate_has_child_subreaper(struct task_struct *p, void *data) +{ + /* + * If task has has_child_subreaper - all its decendants + * already have these flag too and new decendants will + * inherit it on fork, skip them. + * + * If we've found child_reaper - skip descendants in + * it's subtree as they will never get out pidns. + */ + if (p->signal->has_child_subreaper || + is_child_reaper(task_pid(p))) + return 0; + + p->signal->has_child_subreaper = 1; + return 1; +} + SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) { @@ -2214,6 +2232,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, break; case PR_SET_CHILD_SUBREAPER: me->signal->is_child_subreaper = !!arg2; + if (!arg2) + break; + + walk_process_tree(me, propagate_has_child_subreaper, NULL); break; case PR_GET_CHILD_SUBREAPER: error = put_user(me->signal->is_child_subreaper, |