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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2012-02-17 10:29:20 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-02-17 10:29:32 +0100 |
| commit | f3612304ee04a1a36ded7604771ea56d818158cb (patch) | |
| tree | 3be2e76a2a7929890b02bad3e6ed189419def3bc /arch/s390/kernel | |
| parent | i387: move AMD K7/K8 fpu fxsave/fxrstor workaround from save to restore (diff) | |
| download | linux-f3612304ee04a1a36ded7604771ea56d818158cb.tar.xz linux-f3612304ee04a1a36ded7604771ea56d818158cb.zip | |
[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')
| -rw-r--r-- | arch/s390/kernel/process.c | 5 |
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(); |