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,
David Herrmann <dh.herrmann@gmail.com>
Subject: Re: possible deadlock in lru_add_drain_all
Date: Tue, 31 Oct 2017 17:30:58 +0100 [thread overview]
Message-ID: <20171031163058.2byfed2i36fcum3g@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20171031154546.ouryhw4rtpbrch2f@dhcp22.suse.cz>
On Tue, Oct 31, 2017 at 04:45:46PM +0100, Michal Hocko wrote:
> Anyway, this lock dependecy is subtle as hell and I am worried that we
> might have way too many of those. We have so many callers of
> get_online_cpus that dependecies like this are just waiting to blow up.
Yes, the filesystem locks inside hotplug thing is totally annoying. I've
got a few other splats that contain a similar theme and I've no real
clue what to do about.
See for instance this one:
https://lkml.kernel.org/r/20171027151137.GC3165@worktop.lehotels.local
splice from devtmpfs is another common theme and links it do the
pipe->mutex, which then makes another other splice op invert against
that hotplug crap :/
I'm sure I've suggested simply creating possible_cpus devtmpfs files up
front to get around this... maybe we should just do that.
next prev parent reply other threads:[~2017-10-31 16:31 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
2017-10-31 15:45 ` Michal Hocko
2017-10-31 16:30 ` Peter Zijlstra [this message]
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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