diff options
author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-01-14 17:11:39 +1100 |
---|---|---|
committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-01-15 13:59:03 +1100 |
commit | 0215f7d8c53fb192cd4491ede0ece5cca6b5db57 (patch) | |
tree | 3c72b3f85caf97ec9a2d42367a32a06df5623e1a | |
parent | 30c826358d10c1d6f8147de3310b97488daec830 (diff) |
powerpc: Fix races with irq_work
If we set irq_work on a processor and immediately afterward, before the
irq work has a chance to be processed, we change the decrementer value,
we can seriously delay the handling of that irq_work.
Fix it by checking in a few places for pending irq work, first before
changing the decrementer in decrementer_set_next_event() and after
changing it in the same function and in timer_interrupt().
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r-- | arch/powerpc/kernel/time.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index afb1b56ef4fa..b3dab20acf34 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -536,6 +536,9 @@ void timer_interrupt(struct pt_regs * regs) now = *next_tb - now; if (now <= DECREMENTER_MAX) set_dec((int)now); + /* We may have raced with new irq work */ + if (test_irq_work_pending()) + set_dec(1); __get_cpu_var(irq_stat).timer_irqs_others++; } @@ -802,8 +805,16 @@ static void __init clocksource_init(void) static int decrementer_set_next_event(unsigned long evt, struct clock_event_device *dev) { + /* Don't adjust the decrementer if some irq work is pending */ + if (test_irq_work_pending()) + return 0; __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt; set_dec(evt); + + /* We may have raced with new irq work */ + if (test_irq_work_pending()) + set_dec(1); + return 0; } |