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authorHeiko Carstens <heiko.carstens@de.ibm.com>2012-02-17 10:29:20 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-02-17 10:29:32 +0100
commitf3612304ee04a1a36ded7604771ea56d818158cb (patch)
tree3be2e76a2a7929890b02bad3e6ed189419def3bc /arch/s390/kernel/process.c
parent4903062b5485f0e2c286a23b44c9b59d9b017d53 (diff)
downloadop-kernel-dev-f3612304ee04a1a36ded7604771ea56d818158cb.zip
op-kernel-dev-f3612304ee04a1a36ded7604771ea56d818158cb.tar.gz
[S390] idle: avoid RCU usage in extended quiescent state
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>
Diffstat (limited to 'arch/s390/kernel/process.c')
-rw-r--r--arch/s390/kernel/process.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 3201ae4..4261aa7 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -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();
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