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[S390] idle: avoid RCU usage in extended quiescent state

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Avoid calling wake_up() from our NMI "bottom halve" from RCU extended
quiescent state in idle. wake_up() has RCU read-side critical sections
but this will be completely ignored by RCU if the cpu is in extended
quiescent state.
Which means that whatever object is being accessed from within the
read-side critical section can be freed concurrently from a different
cpu.
So make sure we leave extended quiescent state before calling wake_up().

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2012-02-17 10:29:20 +01:00 committed by Martin Schwidefsky
parent 4903062b54
commit f3612304ee
1 changed files with 3 additions and 2 deletions
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5
arch/s390/kernel/process.c
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@ -76,7 +76,6 @@ static void default_idle(void)
if (test_thread_flag(TIF_MCCK_PENDING)) {
local_mcck_enable();
local_irq_enable();
s390_handle_mcck();
return;
}
trace_hardirqs_on();
@ -93,10 +92,12 @@ void cpu_idle(void)
for (;;) {
tick_nohz_idle_enter();
rcu_idle_enter();
while (!need_resched())
while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING))
default_idle();
rcu_idle_exit();
tick_nohz_idle_exit();
if (test_thread_flag(TIF_MCCK_PENDING))
s390_handle_mcck();
preempt_enable_no_resched();
schedule();
preempt_disable();