There is no reason for rcu_read_lock() in __exit_signal(). tsk->sighand can
only be changed if tsk does exec, obviously this is not possible.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- 26-rc2/kernel/exit.c~0_ES_NO_RCU 2008-05-26 18:09:12.000000000 +0400
+++ 26-rc2/kernel/exit.c 2008-05-31 20:08:11.000000000 +0400
@@ -84,7 +84,6 @@ static void __exit_signal(struct task_st
BUG_ON(!sig);
BUG_ON(!atomic_read(&sig->count));
- rcu_read_lock();
sighand = rcu_dereference(tsk->sighand);
spin_lock(&sighand->siglock);
@@ -135,7 +134,6 @@ static void __exit_signal(struct task_st
tsk->signal = NULL;
tsk->sighand = NULL;
spin_unlock(&sighand->siglock);
- rcu_read_unlock();
__cleanup_sighand(sighand);
clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
--