From 51f8bd6db591689fa1c67628b4cfe9778e76be6d Mon Sep 17 00:00:00 2001 From: Mateusz Guzik Date: Tue, 19 Nov 2024 15:35:26 +0100 Subject: [PATCH] get_task_exe_file: check PF_KTHREAD locklessly Same thing as 8ac5dc66599c ("get_task_mm: check PF_KTHREAD lockless") Nowadays PF_KTHREAD is sticky and it was never protected by ->alloc_lock. Move the PF_KTHREAD check outside of task_lock() section to make this code more understandable. Link: https://lkml.kernel.org/r/20241119143526.704986-1-mjguzik@gmail.com Signed-off-by: Mateusz Guzik Acked-by: Oleg Nesterov Signed-off-by: Andrew Morton --- kernel/fork.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 9b301180fd41..19d7fe31869b 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1514,12 +1514,13 @@ struct file *get_task_exe_file(struct task_struct *task) struct file *exe_file = NULL; struct mm_struct *mm; + if (task->flags & PF_KTHREAD) + return NULL; + task_lock(task); mm = task->mm; - if (mm) { - if (!(task->flags & PF_KTHREAD)) - exe_file = get_mm_exe_file(mm); - } + if (mm) + exe_file = get_mm_exe_file(mm); task_unlock(task); return exe_file; } -- 2.50.1