From: Miaohe Lin <linmiaohe@huawei.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>,
Zhouyi Zhou <zhouzhouyi@gmail.com>, <paulmck@kernel.org>,
Oleksandr Natalenko <oleksandr@natalenko.name>,
linux-kernel <linux-kernel@vger.kernel.org>,
<stable@vger.kernel.org>,
Chris Clayton <chris2553@googlemail.com>,
Chris Rankin <rankincj@gmail.com>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
rcu <rcu@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
"Huang, Ying" <ying.huang@intel.com>,
<gregkh@linuxfoundation.org>
Subject: Re: linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359
Date: Mon, 19 Jul 2021 19:50:07 +0800 [thread overview]
Message-ID: <8058e175-cec5-c243-6499-c1cd4e3c8605@huawei.com> (raw)
In-Reply-To: <YPVgaY6uw59Fqg5x@casper.infradead.org>
On 2021/7/19 19:22, Matthew Wilcox wrote:
> On Mon, Jul 19, 2021 at 07:12:58PM +0800, Miaohe Lin wrote:
>> When in the commit 2799e77529c2a, we're using the percpu_ref to serialize against
>> concurrent swapoff, i.e. there's percpu_ref inside get_swap_device() instead of
>> rcu_read_lock(). Please see commit 63d8620ecf93 ("mm/swapfile: use percpu_ref to
>> serialize against concurrent swapoff") for detail.
>
> Oh, so this is a backport problem. 2799e77529c2 was backported without
> its prerequisite 63d8620ecf93. Greg, probably best to just drop
Yes, they're posted as a patch set:
https://lkml.kernel.org/r/20210426123316.806267-1-linmiaohe@huawei.com
> 2799e77529c2 from all stable trees; the race described is not very
> important (swapoff vs reading a page back from that swap device).
> .
>
The swapoff races with reading a page back from that swap device should be really
uncommon as most users only do swapoff when the system is going to shutdown.
Sorry for the trouble!
next prev parent reply other threads:[~2021-07-19 11:50 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <c9fd1311-662c-f993-c8ef-54af036f2f78@googlemail.com>
2021-07-18 21:01 ` linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359 Oleksandr Natalenko
2021-07-18 21:03 ` Oleksandr Natalenko
2021-07-18 21:22 ` Matthew Wilcox
2021-07-18 21:36 ` Chris Clayton
2021-07-18 21:59 ` Paul E. McKenney
2021-07-18 22:51 ` Matthew Wilcox
2021-07-19 1:53 ` Paul E. McKenney
2021-07-19 2:24 ` Zhouyi Zhou
2021-07-19 2:27 ` Zhouyi Zhou
2021-07-19 2:43 ` Matthew Wilcox
2021-07-19 2:59 ` Zhouyi Zhou
2021-07-19 10:14 ` Boqun Feng
2021-07-19 11:12 ` Miaohe Lin
2021-07-19 11:17 ` Oleksandr Natalenko
2021-07-19 11:22 ` Matthew Wilcox
2021-07-19 11:50 ` Miaohe Lin [this message]
2021-07-19 11:59 ` Oleksandr Natalenko
2021-07-19 12:08 ` Miaohe Lin
2021-07-19 12:12 ` Oleksandr Natalenko
2021-07-19 12:16 ` Matthew Wilcox
2021-07-19 12:23 ` Oleksandr Natalenko
2021-07-19 16:47 ` Zhouyi Zhou
2021-07-19 16:56 ` Zhouyi Zhou
2021-07-22 7:30 ` Chris Clayton
2021-07-22 8:57 ` Zhouyi Zhou
2021-07-22 12:36 ` Matthew Wilcox
2021-07-22 13:26 ` Greg KH
2021-07-22 14:00 ` Greg KH
2021-07-23 1:51 ` Miaohe Lin
2021-07-23 7:02 ` Greg KH
2021-07-23 7:13 ` Miaohe Lin
2021-07-22 17:44 ` Zhouyi Zhou
2021-07-22 14:05 ` Paul E. McKenney
2021-07-19 12:17 ` Miaohe Lin
2021-07-19 7:32 ` Chris Clayton
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