forked from luck/tmp_suning_uos_patched
watchdog/softlockup: Fix cpu_stop_queue_work() double-queue bug
When scheduling is delayed for longer than the softlockup interrupt
period it is possible to double-queue the cpu_stop_work, causing list
corruption.
Cure this by adding a completion to track the cpu_stop_work's
progress.
Reported-by: kernel test robot <lkp@intel.com>
Tested-by: Rong Chen <rong.a.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 9cf57731b6
("watchdog/softlockup: Replace "watchdog/%u" threads with cpu_stop_work")
Link: http://lkml.kernel.org/r/20180713104208.GW2494@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
fdf2ceb7f5
commit
be45bf5395
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@ -330,6 +330,9 @@ static void watchdog_interrupt_count(void)
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__this_cpu_inc(hrtimer_interrupts);
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}
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static DEFINE_PER_CPU(struct completion, softlockup_completion);
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static DEFINE_PER_CPU(struct cpu_stop_work, softlockup_stop_work);
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/*
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* The watchdog thread function - touches the timestamp.
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*
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@ -343,12 +346,11 @@ static int softlockup_fn(void *data)
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__this_cpu_write(soft_lockup_hrtimer_cnt,
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__this_cpu_read(hrtimer_interrupts));
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__touch_watchdog();
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complete(this_cpu_ptr(&softlockup_completion));
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return 0;
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}
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static DEFINE_PER_CPU(struct cpu_stop_work, softlockup_stop_work);
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/* watchdog kicker functions */
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static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
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{
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@ -364,9 +366,12 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
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watchdog_interrupt_count();
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/* kick the softlockup detector */
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stop_one_cpu_nowait(smp_processor_id(),
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softlockup_fn, NULL,
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this_cpu_ptr(&softlockup_stop_work));
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if (completion_done(this_cpu_ptr(&softlockup_completion))) {
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reinit_completion(this_cpu_ptr(&softlockup_completion));
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stop_one_cpu_nowait(smp_processor_id(),
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softlockup_fn, NULL,
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this_cpu_ptr(&softlockup_stop_work));
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}
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/* .. and repeat */
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hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
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@ -467,9 +472,13 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
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static void watchdog_enable(unsigned int cpu)
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{
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struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);
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struct completion *done = this_cpu_ptr(&softlockup_completion);
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WARN_ON_ONCE(cpu != smp_processor_id());
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init_completion(done);
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complete(done);
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/*
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* Start the timer first to prevent the NMI watchdog triggering
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* before the timer has a chance to fire.
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@ -499,6 +508,7 @@ static void watchdog_disable(unsigned int cpu)
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*/
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watchdog_nmi_disable(cpu);
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hrtimer_cancel(hrtimer);
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wait_for_completion(this_cpu_ptr(&softlockup_completion));
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}
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static int softlockup_stop_fn(void *data)
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