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Date: Wed, 22 Jul 2015 14:59:16 +0800 From: yalin wang <yalin.wang2010@...il.com> To: Spencer Baugh <sbaugh@...ern.com> Cc: Don Zickus <dzickus@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, Ulrich Obergfell <uobergfe@...hat.com>, Ingo Molnar <mingo@...nel.org>, Andrew Jones <drjones@...hat.com>, chai wen <chaiw.fnst@...fujitsu.com>, Chris Metcalf <cmetcalf@...hip.com>, Stephane Eranian <eranian@...gle.com>, open list <linux-kernel@...r.kernel.org>, Joern Engel <joern@...estorage.com>, Spencer Baugh <Spencer.baugh@...estorage.com>, Joern Engel <joern@...fs.org> Subject: Re: [PATCH] soft lockup: kill realtime threads before panic > On Jul 22, 2015, at 06:07, Spencer Baugh <sbaugh@...ern.com> wrote: > > From: Joern Engel <joern@...fs.org> > > We have observed cases where the soft lockup detector triggered, but no > kernel bug existed. Instead we had a buggy realtime thread that > monopolized a cpu. So let's kill the responsible party and not panic > the entire system. > > Signed-off-by: Joern Engel <joern@...fs.org> > Signed-off-by: Spencer Baugh <sbaugh@...ern.com> > --- > kernel/watchdog.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index a6ffa43..2355bd5 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -428,7 +428,10 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) > } > > add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK); > - if (softlockup_panic) > + if (rt_prio(current->prio)) { > + pr_emerg("killing realtime thread\n"); > + send_sig(SIGILL, current, 0); > + } else if (softlockup_panic) > panic("softlockup: hung tasks"); > __this_cpu_write(soft_watchdog_warn, true); > } else > -- just my advice about this patch, i think should add PF_KTHREAD condition like this: if (rt_prio(current->prio) && !(current->flags & PF_KTHREAD)) { + pr_emerg("killing realtime thread\n"); + send_sig(SIGILL, current, 0); + } else if (softlockup_panic) if soft lockup is caused by kthread, should still panic . Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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