diff options
| author | Oleg Nesterov <[email protected]> | 2024-02-02 14:12:26 +0100 |
|---|---|---|
| committer | Christian Brauner <[email protected]> | 2024-02-02 14:57:53 +0100 |
| commit | 43f0df54c96fa5abcab9df8649c1e52119bf0238 (patch) | |
| tree | 3233889920853f7ea8355d41d33f084dad59f799 | |
| parent | 64bef697d33b75fc06c5789b3f8108680271529f (diff) | |
pidfd_poll: report POLLHUP when pid_task() == NULL
Add another wake_up_all(wait_pidfd) into __change_pid() and change
pidfd_poll() to include EPOLLHUP if task == NULL.
This allows to wait until the target process/thread is reaped.
TODO: change do_notify_pidfd() to use the keyed wakeups.
Signed-off-by: Oleg Nesterov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>
| -rw-r--r-- | kernel/fork.c | 22 | ||||
| -rw-r--r-- | kernel/pid.c | 5 |
2 files changed, 12 insertions, 15 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 1a9b91055916..aa08193d124f 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2071,20 +2071,6 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) } #endif -static bool pidfd_task_exited(struct pid *pid, bool thread) -{ - struct task_struct *task; - bool exited; - - rcu_read_lock(); - task = pid_task(pid, PIDTYPE_PID); - exited = !task || - (READ_ONCE(task->exit_state) && (thread || thread_group_empty(task))); - rcu_read_unlock(); - - return exited; -} - /* * Poll support for process exit notification. */ @@ -2092,6 +2078,7 @@ static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts) { struct pid *pid = file->private_data; bool thread = file->f_flags & PIDFD_THREAD; + struct task_struct *task; __poll_t poll_flags = 0; poll_wait(file, &pid->wait_pidfd, pts); @@ -2099,8 +2086,13 @@ static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts) * Depending on PIDFD_THREAD, inform pollers when the thread * or the whole thread-group exits. */ - if (pidfd_task_exited(pid, thread)) + rcu_read_lock(); + task = pid_task(pid, PIDTYPE_PID); + if (!task) + poll_flags = EPOLLIN | EPOLLRDNORM | EPOLLHUP; + else if (task->exit_state && (thread || thread_group_empty(task))) poll_flags = EPOLLIN | EPOLLRDNORM; + rcu_read_unlock(); return poll_flags; } diff --git a/kernel/pid.c b/kernel/pid.c index e11144466828..62461c7c82b8 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -349,6 +349,11 @@ static void __change_pid(struct task_struct *task, enum pid_type type, hlist_del_rcu(&task->pid_links[type]); *pid_ptr = new; + if (type == PIDTYPE_PID) { + WARN_ON_ONCE(pid_has_task(pid, PIDTYPE_PID)); + wake_up_all(&pid->wait_pidfd); + } + for (tmp = PIDTYPE_MAX; --tmp >= 0; ) if (pid_has_task(pid, tmp)) return; |