From: Oleg Nesterov <oleg@xxxxxxxxxx>
If some system uses multi-threaded init the kernel panics when the main
thread exits. Perhaps this is just a "quality of implementation" question.
sys_exit() from the main thread should be OK, why /sbin/init should be
special? That said, I personally do not think that multi-threaded init is
terribly useful.
So I think the patch below makes sense for now. Note that it removes
the games with pid_ns->child_reaper: this doesn't work currently, and
this has to be modified when we actually support pid namespaces anyway.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
---
exit.c | 17 +++++++++--------
1 files changed, 9 insertions(+), 8 deletions(-)
--- ./kernel/exit.c.ve3 2007-08-06 12:14:53.000000000 +0400
+++ ./kernel/exit.c 2007-08-06 12:15:19.000000000 +0400
@@ -895,6 +895,14 @@ static void check_stack_usage(void)
static inline void check_stack_usage(void) {}
#endif
+static inline void exit_child_reaper(struct task_struct *tsk)
+{
+ if (likely(tsk->group_leader != task_child_reaper(tsk)))
+ return;
+
+ panic("Attempted to kill init!");
+}
+
fastcall NORET_TYPE void do_exit(long code)
{
struct task_struct *tsk = current;
@@ -908,14 +916,6 @@ fastcall NORET_TYPE void do_exit(long co
panic("Aiee, killing interrupt handler!");
if (unlikely(!tsk->pid))
panic("Attempted to kill the idle task!");
- if (unlikely(tsk == task_child_reaper(tsk))) {
- if (task_active_pid_ns(tsk) != &init_pid_ns)
- task_active_pid_ns(tsk)->child_reaper =
- init_pid_ns.child_reaper;
- else
- panic("Attempted to kill init!");
- }
-
if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
current->ptrace_message = code;
@@ -965,6 +965,7 @@ fastcall NORET_TYPE void do_exit(long co
}
group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) {
+ exit_child_reaper(tsk);
hrtimer_cancel(&tsk->signal->real_timer);
exit_itimers(tsk->signal);
}
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