sh: fix xtime_lock deadlocking.
move update_process_times() out from under xtime_lock.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/time_32.c b/arch/sh/kernel/time_32.c
index 2bc04bf..7281342 100644
--- a/arch/sh/kernel/time_32.c
+++ b/arch/sh/kernel/time_32.c
@@ -120,10 +120,6 @@
*/
void handle_timer_tick(void)
{
- do_timer(1);
-#ifndef CONFIG_SMP
- update_process_times(user_mode(get_irq_regs()));
-#endif
if (current->pid)
profile_tick(CPU_PROFILING);
@@ -133,6 +129,16 @@
#endif
/*
+ * Here we are in the timer irq handler. We just have irqs locally
+ * disabled but we don't know if the timer_bh is running on the other
+ * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
+ * the irq version of write_lock because as just said we have irq
+ * locally disabled. -arca
+ */
+ write_seqlock(&xtime_lock);
+ do_timer(1);
+
+ /*
* If we have an externally synchronized Linux clock, then update
* RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
* called as close as possible to 500 ms before the new second starts.
@@ -147,6 +153,11 @@
/* do it again in 60s */
last_rtc_update = xtime.tv_sec - 600;
}
+ write_sequnlock(&xtime_lock);
+
+#ifndef CONFIG_SMP
+ update_process_times(user_mode(get_irq_regs()));
+#endif
}
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */