From: Dmitry Vyukov <dvyukov@google.com>
To: Byungchul Park <byungchul.park@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@kernel.org>,
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>,
Jerome Glisse <jglisse@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <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: Wed, 14 Feb 2018 15:01:38 +0100 [thread overview]
Message-ID: <CACT4Y+bvUmjkGDqoOGtMSBfqvbwF4=e8ZyiYYfq0kiVov8Ebiw@mail.gmail.com> (raw)
In-Reply-To: <20171101235456.GA3928@X58A-UD3R>
On Thu, Nov 2, 2017 at 12:54 AM, Byungchul Park <byungchul.park@lge.com> wrote:
> On Wed, Nov 01, 2017 at 01:01:01PM +0100, Peter Zijlstra wrote:
>> On Wed, Nov 01, 2017 at 05:59:27PM +0900, Byungchul Park wrote:
>> > On Tue, Oct 31, 2017 at 04:10:24PM +0100, Peter Zijlstra wrote:
>> > > On Tue, Oct 31, 2017 at 03:58:04PM +0100, Michal Hocko wrote:
>> > > > On Tue 31-10-17 15:52:47, Peter Zijlstra wrote:
>> > > > [...]
>> > > > > If we want to save those stacks; we have to save a stacktrace on _every_
>> > > > > lock acquire, simply because we never know ahead of time if there will
>> > > > > be a new link. Doing this is _expensive_.
>> > > > >
>> > > > > Furthermore, the space into which we store stacktraces is limited;
>> > > > > since memory allocators use locks we can't very well use dynamic memory
>> > > > > for lockdep -- that would give recursive and robustness issues.
>> >
>> > I agree with all you said.
>> >
>> > But, I have a better idea, that is, to save only the caller's ip of each
>> > acquisition as an additional information? Of course, it's not enough in
>> > some cases, but it's cheep and better than doing nothing.
>> >
>> > For example, when building A->B, let's save not only full stack of B,
>> > but also caller's ip of A together, then use them on warning like:
>>
>> Like said; I've never really had trouble finding where we take A. And
>
> Me, either, since I know the way. But I've seen many guys who got
> confused with it, which is why I suggested it.
>
> But, leave it if you don't think so.
>
>> for the most difficult cases, just the IP isn't too useful either.
>>
>> So that would solve a non problem while leaving the real problem.
Hi,
What's the status of this? Was any patch submitted for this?
next prev parent reply other threads:[~2018-02-14 14:02 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 [this message]
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
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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