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authorHeiko Carstens <heiko.carstens@de.ibm.com>2012-02-17 13:29:20 +0400
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-02-17 13:29:32 +0400
commitf3612304ee04a1a36ded7604771ea56d818158cb (patch)
tree3be2e76a2a7929890b02bad3e6ed189419def3bc /arch/s390
parent4903062b5485f0e2c286a23b44c9b59d9b017d53 (diff)
downloadlinux-f3612304ee04a1a36ded7604771ea56d818158cb.tar.xz
[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')
-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 3201ae447990..4261aa799774 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();