exit: hoist get_pid() in release_task() outside of tasklist_lock

Reduces hold time as get_pid() contains an atomic.

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250206164415.450051-3-mjguzik@gmail.com
Acked-by: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/kernel/exit.c b/kernel/exit.c
index a00273db024b3a5de0b23570fab690e80d495e2f..ebc1c5bec51220611d527b30045398170cfea81e 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -240,9 +240,10 @@ repeat:
 
        cgroup_release(p);
 
+       thread_pid = get_pid(p->thread_pid);
+
        write_lock_irq(&tasklist_lock);
        ptrace_release_task(p);
-       thread_pid = get_pid(p->thread_pid);
        __exit_signal(p);
 
        /*