Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers"

This reverts commit abdfd4948e45c51b19162cf8b3f5003f8f53c9b9.

The changelog in this commit explains why it is not easy to avoid ns == NULL
when the caller is exiting, but pid_vnr() is equally unsafe in this case.

However, commit 006568ab4c5c ("pid: Add a judgment for ns null in pid_nr_ns")
already added the ns != NULL check in pid_nr_ns(), so we can remove the same
check from __task_pid_nr_ns().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://patch.msgid.link/20251015123613.GA9456@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/kernel/pid.c b/kernel/pid.c
index 72c9372b84b8f8f9572f44d272cf1162ed250ac8..3b96571d0fe652bbcc22fc80895c4e21df89f16c 100644 (file)
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -558,8 +558,7 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
        rcu_read_lock();
        if (!ns)
                ns = task_active_pid_ns(current);
-       if (ns)
-               nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
+       nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
        rcu_read_unlock();
 
        return nr;