[PATCH v2 1/2] exit: move wake_up_all() pidfd waiters into __unhash_process()

Christian Brauner
2025-04-11T13:22:55Z

Move the pidfd notification out of __change_pid() and into
__unhash_process(). The only valid call to __change_pid() with a NULL
argument and PIDTYPE_PID is from __unhash_process(). This is a lot more
obvious than calling it from __change_pid().

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
kernel/exit.c | 5 +++++
kernel/pid.c | 5 -----
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index 1b51dc099f1e..abcd93ce4e18 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -133,8 +133,13 @@ struct release_task_post {
static void __unhash_process(struct release_task_post *post, struct task_struct *p,
bool group_dead)
{
+ struct pid *pid = task_pid(p);
+
nr_threads--;
+
detach_pid(post->pids, p, PIDTYPE_PID);
+ wake_up_all(&pid->wait_pidfd);
+
if (group_dead) {
detach_pid(post->pids, p, PIDTYPE_TGID);
detach_pid(post->pids, p, PIDTYPE_PGID);
diff --git a/kernel/pid.c b/kernel/pid.c
index 4ac2ce46817f..26f1e136f017 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -359,11 +359,6 @@ static void __change_pid(struct pid **pids, struct task_struct *task,
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;

--
2.47.2