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From: Peter Zijlstra <peterz@infradead.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Byungchul Park <byungchul.park@lge.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	syzbot 
	<bot+e7353c7141ff7cbb718e4c888a14fa92de41ebaa@syzkaller.appspotmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Johannes Weiner <hannes@cmpxchg.org>, Jan Kara <jack@suse.cz>,
	jglisse@redhat.com, LKML <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, shli@fb.com, syzkaller-bugs@googlegroups.com,
	Thomas Gleixner <tglx@linutronix.de>,
	Vlastimil Babka <vbabka@suse.cz>,
	ying.huang@intel.com, kernel-team@lge.com
Subject: Re: possible deadlock in lru_add_drain_all
Date: Tue, 31 Oct 2017 16:25:32 +0100	[thread overview]
Message-ID: <20171031152532.uah32qiftjerc3gx@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20171031131333.pr2ophwd2bsvxc3l@dhcp22.suse.cz>

On Tue, Oct 31, 2017 at 02:13:33PM +0100, Michal Hocko wrote:

> > I can indeed confirm it's running old code; cpuhp_state is no more.
> 
> Does this mean the below chain is no longer possible with the current
> linux-next (tip)?

I see I failed to answer this; no it will happen but now reads like:

	s/cpuhp_state/&_up/

Where we used to have a single lock protecting the hotplug stuff, we now
have 2, one for bringing stuff up and one for tearing it down.

This got rid of lock cycles that included cpu-up and cpu-down parts;
those are false positives because we cannot do cpu-up and cpu-down
concurrently.

But this report only includes a single (cpu-up) part and therefore is
not affected by that change other than a lock name changing.

  parent reply	other threads:[~2017-10-31 15:26 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <089e0825eec8955c1f055c83d476@google.com>
2017-10-27  9:34 ` possible deadlock in lru_add_drain_all Michal Hocko
2017-10-27  9:44   ` Dmitry Vyukov
2017-10-27  9:47     ` Dmitry Vyukov
2017-10-27 13:42     ` Michal Hocko
2017-10-30  8:22       ` Michal Hocko
2017-10-30 10:09         ` Byungchul Park
2017-10-30 15:10           ` Peter Zijlstra
2017-10-30 15:22             ` Peter Zijlstra
2017-10-31 13:13             ` Michal Hocko
2017-10-31 13:51               ` Peter Zijlstra
2017-10-31 13:55                 ` Dmitry Vyukov
2017-10-31 14:52                   ` Peter Zijlstra
2017-10-31 14:58                     ` Michal Hocko
2017-10-31 15:10                       ` Peter Zijlstra
2017-11-01  8:59                         ` Byungchul Park
2017-11-01 12:01                           ` Peter Zijlstra
2017-11-01 23:54                             ` Byungchul Park
2018-02-14 14:01                               ` Dmitry Vyukov
2018-02-14 15:44                                 ` Michal Hocko
2018-02-14 15:57                                   ` Dmitry Vyukov
2017-10-31 15:25               ` Peter Zijlstra [this message]
2017-10-31 15:45                 ` Michal Hocko
2017-10-31 16:30                   ` Peter Zijlstra
2017-11-01  8:31                 ` Byungchul Park
2017-10-30 10:26         ` Byungchul Park
2017-10-30 11:48           ` Michal Hocko
2017-10-27 11:27   ` Vlastimil Babka

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