The patch titled
Subject: get_task_exe_file: check PF_KTHREAD locklessly
has been added to the -mm mm-nonmm-unstable branch. Its filename is
get_task_exe_file-check-pf_kthread-locklessly.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/get_task_exe_file-check-pf_kthread-locklessly.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Mateusz Guzik <mjguzik@xxxxxxxxx>
Subject: get_task_exe_file: check PF_KTHREAD locklessly
Date: Tue, 19 Nov 2024 15:35:26 +0100
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@xxxxxxxxx
Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
--- a/kernel/fork.c~get_task_exe_file-check-pf_kthread-locklessly
+++ a/kernel/fork.c
@@ -1496,12 +1496,13 @@ struct file *get_task_exe_file(struct ta
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;
}
_
Patches currently in -mm which might be from mjguzik@xxxxxxxxx are
get_task_exe_file-check-pf_kthread-locklessly.patch
