The major differences of creating a new thread from creating a
new process is that
1. newbie's tgid is set to leader's
2. newbie's leader is set to leader
3. newbie is added to leader's thread_list
So move the initialization of these in one place. This helps
in pid/tgid fields isolation.
Signed-off-by: Pavel Emelyanov <[EMAIL PROTECTED]>
---
diff --git a/kernel/fork.c b/kernel/fork.c
index 7517efe..0b282a8 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -950,6 +950,20 @@ static inline void rt_mutex_init_task(st
#endif
}
+static void setup_new_thread(struct task_struct *thr, struct task_struct
*leader)
+{
+ thr->tgid = leader->tgid;
+ thr->group_leader = leader;
+ list_add_tail_rcu(&thr->thread_group, &leader->thread_group);
+}
+
+static void setup_new_leader(struct task_struct *tsk)
+{
+ tsk->tgid = task_pid_nr(tsk);
+ tsk->group_leader = tsk;
+ INIT_LIST_HEAD(&tsk->thread_group);
+}
+
/*
* This creates a new process as a copy of the old one,
* but does not actually start it yet.
@@ -1147,9 +1161,6 @@ static struct task_struct *copy_process(
}
p->pid = pid_nr(pid);
- p->tgid = p->pid;
- if (clone_flags & CLONE_THREAD)
- p->tgid = current->tgid;
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr :
NULL;
/*
@@ -1191,8 +1202,6 @@ static struct task_struct *copy_process(
* Ok, make it visible to the rest of the system.
* We dont wake it up yet.
*/
- p->group_leader = p;
- INIT_LIST_HEAD(&p->thread_group);
INIT_LIST_HEAD(&p->ptrace_children);
INIT_LIST_HEAD(&p->ptrace_list);
@@ -1251,8 +1260,7 @@ static struct task_struct *copy_process(
}
if (clone_flags & CLONE_THREAD) {
- p->group_leader = current->group_leader;
- list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
+ setup_new_thread(p, current->group_leader);
if (!cputime_eq(current->signal->it_virt_expires,
cputime_zero) ||
@@ -1268,7 +1276,8 @@ static struct task_struct *copy_process(
*/
p->it_prof_expires = jiffies_to_cputime(1);
}
- }
+ } else
+ setup_new_leader(p);
if (likely(p->pid)) {
add_parent(p);
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