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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455// SPDX-License-Identifier: GPL-2.0-or-later/* Function to determine if a thread group is single threaded or not * * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - Derived from security/selinux/hooks.c */#include <linux/sched/signal.h>#include <linux/sched/task.h>#include <linux/sched/mm.h>
/* * Returns true if the task does not share ->mm with another thread/process. */bool current_is_single_threaded(void){ struct task_struct *task = current; struct mm_struct *mm = task->mm; struct task_struct *p, *t; bool ret;
if (atomic_read(&task->signal->live) != 1) return false;
if (atomic_read(&mm->mm_users) == 1) return true;
ret = false; rcu_read_lock(); for_each_process(p) { if (unlikely(p->flags & PF_KTHREAD)) continue; if (unlikely(p == task->group_leader)) continue;
for_each_thread(p, t) { if (unlikely(t->mm == mm)) goto found; if (likely(t->mm)) break; /* * t->mm == NULL. Make sure next_thread/next_task * will see other CLONE_VM tasks which might be * forked before exiting. */ smp_rmb(); } } ret = true;found: rcu_read_unlock();
return ret;}