Messages in this thread | | | Date | Wed, 15 Sep 2021 15:45:06 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/5] kernel/watchdog_hld: clarify the condition in hardlockup_detector_event_create() |
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On Wed, Sep 15, 2021 at 11:51:00AM +0800, Pingfan Liu wrote: > hardlockup_detector_event_create() indirectly calls > kmem_cache_alloc_node(), which is blockable. > > So here, the really planned context is is_percpu_thread(). > > Signed-off-by: Pingfan Liu <kernelfans@gmail.com> > Cc: Petr Mladek <pmladek@suse.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Wang Qing <wangqing@vivo.com> > Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> > Cc: Santosh Sivaraj <santosh@fossix.org> > Cc: Sumit Garg <sumit.garg@linaro.org> > Cc: Will Deacon <will@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > To: linux-kernel@vger.kernel.org > --- > kernel/watchdog_hld.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c > index 247bf0b1582c..6876e796dbf5 100644 > --- a/kernel/watchdog_hld.c > +++ b/kernel/watchdog_hld.c > @@ -165,10 +165,13 @@ static void watchdog_overflow_callback(struct perf_event *event, > > static int hardlockup_detector_event_create(void) > { > - unsigned int cpu = smp_processor_id(); > + unsigned int cpu; > struct perf_event_attr *wd_attr; > struct perf_event *evt; > > + /* This function plans to execute in cpu bound kthread */ > + BUG_ON(!is_percpu_thread()); > + cpu = raw_smp_processor_id(); > wd_attr = &wd_hw_attr; > wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
This patch makes no sense.
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