From: Michal Hocko <mhocko@kernel.org>
To: sunqiuyang <sunqiuyang@huawei.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH 1/1] mm/migrate: fix list corruption in migration of non-LRU movable pages
Date: Wed, 4 Sep 2019 08:38:36 +0200 [thread overview]
Message-ID: <20190904063836.GD3838@dhcp22.suse.cz> (raw)
In-Reply-To: <157FC541501A9C4C862B2F16FFE316DC190C1B09@dggeml512-mbx.china.huawei.com>
On Wed 04-09-19 02:18:38, sunqiuyang wrote:
> The isolate path of non-lru movable pages:
>
> isolate_migratepages_block
> isolate_movable_page
> trylock_page
> // if PageIsolated, goto out_no_isolated
> a_ops->isolate_page
> __SetPageIsolated
> unlock_page
> list_add(&page->lru, &cc->migratepages)
>
> The migration path:
>
> unmap_and_move
> __unmap_and_move
> lock_page
> move_to_new_page
> a_ops->migratepage
> __ClearPageIsolated
> unlock_page
> /* here, the page could be isolated again by another thread, and added into another cc->migratepages,
> since PG_Isolated has been cleared, and not protected by page_lock */
> list_del(&page->lru)
But the page has been migrated already and not freed yet because there
is still a pin on it. So nobody should be touching it at this stage.
Or do I still miss something?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-09-04 6:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-03 8:27 [PATCH 1/1] mm/migrate: fix list corruption in migration of non-LRU movable pages sunqiuyang
2019-09-03 13:17 ` Michal Hocko
2019-09-04 2:18 ` sunqiuyang
2019-09-04 6:38 ` Michal Hocko [this message]
2019-09-04 7:27 ` sunqiuyang
2019-09-04 8:14 ` Michal Hocko
2019-09-04 12:19 ` sunqiuyang
2019-09-04 12:52 ` Michal Hocko
2019-09-05 1:44 ` sunqiuyang
2019-09-09 8:40 ` Michal Hocko
2019-09-12 17:21 ` Minchan Kim
2019-09-10 19:23 ` Minchan Kim
2019-09-10 19:31 ` Michal Hocko
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