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From: Michal Hocko <mhocko@suse.com>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
	Shakeel Butt <shakeelb@google.com>,
	syzbot <syzbot+506c8a2a115201881d45@syzkaller.appspotmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux MM <linux-mm@kvack.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Eric Dumazet <edumazet@google.com>,
	Mina Almasry <almasrymina@google.com>,
	tglx@linutronix.de, john.ogness@linutronix.de, urezki@gmail.com,
	ast@fb.com
Subject: Re: possible deadlock in sk_clone_lock
Date: Thu, 4 Mar 2021 10:58:39 +0100	[thread overview]
Message-ID: <YECvT4QOitK954Ne@dhcp22.suse.cz> (raw)
In-Reply-To: <20210303175945.GE2696@paulmck-ThinkPad-P72>

On Wed 03-03-21 09:59:45, Paul E. McKenney wrote:
> On Wed, Mar 03, 2021 at 09:03:27AM +0100, Michal Hocko wrote:
[...]
> > Paul what is the current plan with in_atomic to be usable for !PREEMPT
> > configurations?
> 
> Ah, thank you for the reminder!  I have rebased that series on top of
> v5.12-rc1 on -rcu branch tglx-pc.2021.03.03a.
> 
> The current state is that Linus is not convinced that this change is
> worthwhile given that only RCU and printk() want it.  (BPF would use
> it if it were available, but is willing to live without it, at least in
> the short term.)
> 
> But maybe Linus will be convinced given your additional use case.
> Here is hoping!

Yes, hugetlb freeing path would benefit from this. You can reference
this lockdep report (http://lkml.kernel.org/r/000000000000f1c03b05bc43aadc@google.com)
with an additional argument that making hugetlb_lock irq safe is a
larger undertaking and we will need something reasonably backportable
for older kernels as well.
-- 
Michal Hocko
SUSE Labs


      reply	other threads:[~2021-03-04  9:58 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-26 21:08 syzbot
2021-02-26 22:44 ` Shakeel Butt
2021-02-26 23:14   ` Mike Kravetz
2021-02-27  0:00     ` Shakeel Butt
2021-03-01 12:11       ` Michal Hocko
2021-03-01 15:10         ` Shakeel Butt
2021-03-01 15:57           ` Michal Hocko
2021-03-01 16:39             ` Shakeel Butt
2021-03-01 17:23               ` Michal Hocko
2021-03-02  1:16                 ` Mike Kravetz
2021-03-02  9:44                   ` Michal Hocko
     [not found]                     ` <CALvZod7XHbjfoGGVH=h17u8-FruMaiPMWxXJz5JBmeJkNHBqNQ@mail.gmail.com>
     [not found]                       ` <YD5L1K3EWVWh1ULr@dhcp22.suse.cz>
     [not found]                         ` <06edda9a-dce9-accd-11a3-97f6d5243ed1@oracle.com>
2021-03-03  3:59                           ` Shakeel Butt
2021-03-05  9:09                             ` Michal Hocko
2021-03-03  8:03                           ` Michal Hocko
2021-03-03 17:59                             ` Paul E. McKenney
2021-03-04  9:58                               ` Michal Hocko [this message]

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