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| author | Thomas Gleixner <tglx@linutronix.de> | 2015-05-07 14:35:59 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-05-07 16:15:50 +0200 |
| commit | 6b442bc81337913eb775965a67ffdb8a36935422 (patch) | |
| tree | c98932b4f91567c23eb77bb6596a0d1fa5207036 | |
| parent | 38d23a6cc16c02f7b0c920266053f340b5601735 (diff) | |
| download | linux-6b442bc81337913eb775965a67ffdb8a36935422.tar.gz linux-6b442bc81337913eb775965a67ffdb8a36935422.tar.bz2 linux-6b442bc81337913eb775965a67ffdb8a36935422.zip | |
nohz: Fix !HIGH_RES_TIMERS hang
Simon Horman reported this crash on a system with
high-res timers disabled but nohz enabled:
> ------------[ cut here ]------------
> kernel BUG at kernel/irq_work.c:135!
BUG_ON(!irqs_disabled());
So something enabled interrupts in the periodic tick handling machinery,
and that code path indeed has a local_irq_disable()/enable pair in
tick_nohz_switch_to_nohz() which causes havoc. Fix it.
This patch also fixes a +nohz -hrtimers hang reported by Ingo Molnar.
Reported-by: Simon Horman <horms@verge.net.au>
Reported-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: LAK <linux-arm-kernel@lists.infradead.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1505071425520.4225@nanos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/time/tick-sched.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 753c211f6195..812f7a3b9898 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -967,11 +967,9 @@ static void tick_nohz_switch_to_nohz(void) if (!tick_nohz_enabled) return; - local_irq_disable(); - if (tick_switch_to_oneshot(tick_nohz_handler)) { - local_irq_enable(); + if (tick_switch_to_oneshot(tick_nohz_handler)) return; - } + tick_nohz_active = 1; ts->nohz_mode = NOHZ_MODE_LOWRES; @@ -986,7 +984,6 @@ static void tick_nohz_switch_to_nohz(void) hrtimer_forward_now(&ts->sched_timer, tick_period); hrtimer_set_expires(&ts->sched_timer, next); tick_program_event(next, 1); - local_irq_enable(); } /* @@ -1171,7 +1168,7 @@ void tick_oneshot_notify(void) * Called cyclic from the hrtimer softirq (driven by the timer * softirq) allow_nohz signals, that we can switch into low-res nohz * mode, because high resolution timers are disabled (either compile - * or runtime). + * or runtime). Called with interrupts disabled. */ int tick_check_oneshot_change(int allow_nohz) { |