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ptrace: reintroduce __ptrace_detach() as a callee of ptrace_exit()

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No functional changes, preparation for the next patch.

Move the "should we release this child" logic into the separate handler,
__ptrace_detach().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2009-04-02 16:58:13 -07:00 committed by Linus Torvalds
parent 6d69cb87f0
commit b1b4c6799f
1 changed files with 33 additions and 29 deletions
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62
kernel/exit.c
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@ -744,6 +744,38 @@ static int ignoring_children(struct sighand_struct *sigh)
return ret;
}
/* Returns nonzero if the tracee should be released. */
int __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
{
__ptrace_unlink(p);
if (p->exit_state != EXIT_ZOMBIE)
return 0;
/*
* If it's a zombie, our attachedness prevented normal
* parent notification or self-reaping. Do notification
* now if it would have happened earlier. If it should
* reap itself we return true.
*
* If it's our own child, there is no notification to do.
* But if our normal children self-reap, then this child
* was prevented by ptrace and we must reap it now.
*/
if (!task_detached(p) && thread_group_empty(p)) {
if (!same_thread_group(p->real_parent, tracer))
do_notify_parent(p, p->exit_signal);
else if (ignoring_children(tracer->sighand))
p->exit_signal = -1;
}
if (!task_detached(p))
return 0;
/* Mark it as in the process of being reaped. */
p->exit_state = EXIT_DEAD;
return 1;
}
/*
* Detach all tasks we were using ptrace on.
* Any that need to be release_task'd are put on the @dead list.
@ -755,36 +787,8 @@ static void ptrace_exit(struct task_struct *parent, struct list_head *dead)
struct task_struct *p, *n;
list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) {
__ptrace_unlink(p);
if (p->exit_state != EXIT_ZOMBIE)
continue;
/*
* If it's a zombie, our attachedness prevented normal
* parent notification or self-reaping. Do notification
* now if it would have happened earlier. If it should
* reap itself, add it to the @dead list. We can't call
* release_task() here because we already hold tasklist_lock.
*
* If it's our own child, there is no notification to do.
* But if our normal children self-reap, then this child
* was prevented by ptrace and we must reap it now.
*/
if (!task_detached(p) && thread_group_empty(p)) {
if (!same_thread_group(p->real_parent, parent))
do_notify_parent(p, p->exit_signal);
else if (ignoring_children(parent->sighand))
p->exit_signal = -1;
}
if (task_detached(p)) {
/*
* Mark it as in the process of being reaped.
*/
p->exit_state = EXIT_DEAD;
if (__ptrace_detach(parent, p))
list_add(&p->ptrace_entry, dead);
}
}
}