From: Matthew Wilcox <willy@infradead.org>
To: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Miaohe Lin <linmiaohe@huawei.com>,
Boqun Feng <boqun.feng@gmail.com>,
Zhouyi Zhou <zhouzhouyi@gmail.com>,
paulmck@kernel.org, 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 13:16:04 +0100 [thread overview]
Message-ID: <YPVtBBumSTMKGuld@casper.infradead.org> (raw)
In-Reply-To: <5812280.fcLxn8YiTP@natalenko.name>
On Mon, Jul 19, 2021 at 02:12:15PM +0200, Oleksandr Natalenko wrote:
> On pondělí 19. července 2021 14:08:37 CEST Miaohe Lin wrote:
> > On 2021/7/19 19:59, Oleksandr Natalenko wrote:
> > > On pondělí 19. července 2021 13:50:07 CEST Miaohe Lin wrote:
> > >> 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!
> > >
> > > git log --oneline v5.13..v5.13.3 --author="Miaohe Lin"
> > > 11ebc09e50dc mm/zswap.c: fix two bugs in zswap_writeback_entry()
> > > 95d192da198d mm/z3fold: use release_z3fold_page_locked() to release locked
> > > z3fold page
> > > ccb7848e2344 mm/z3fold: fix potential memory leak in z3fold_destroy_pool()
> > > 9f7229c901c1 mm/huge_memory.c: don't discard hugepage if other processes
> > > are mapping it
> > > f13259175e4f mm/huge_memory.c: add missing read-only THP checking in
> > > transparent_hugepage_enabled()
> > > afafd371e7de mm/huge_memory.c: remove dedicated macro
> > > HPAGE_CACHE_INDEX_MASK a533a21b692f mm/shmem: fix shmem_swapin() race
> > > with swapoff
> > > c3b39134bbd0 swap: fix do_swap_page() race with swapoff
> > >
> > > Do you suggest reverting "mm/shmem: fix shmem_swapin() race with swapoff"
> > > as well?
> >
> > This patch also rely on its prerequisite 63d8620ecf93. I think we should
> > either revert any commit in this series or just backport the entire series.
>
> Then why not just pick up 2 more patches instead of dropping 2 patches. Greg,
> could you please make sure the whole series from [1] gets pulled?
Because none of these patches should have been backported in the first
place. It's just not worth the destabilisation.
next prev parent reply other threads:[~2021-07-19 12:17 UTC|newest]
Thread overview: 34+ 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
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 [this message]
2021-07-19 12:23 ` Oleksandr Natalenko
2021-07-19 16:47 ` Zhouyi Zhou
[not found] ` <CAABZP2yh3J8+P=3PLZVaC47ymKC7PcfQCBBxjXJ9Ybn+HREbdg@mail.gmail.com>
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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