From: Andrew Morton <akpm@linux-foundation.org>
To: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: David Hildenbrand <david@redhat.com>,
linux-mm@kvack.org, Muchun Song <songmuchun@bytedance.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@suse.com>, Yang Shi <shy828301@gmail.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>
Subject: Re: [PATCH] mm/huge_memory: use pfn_to_online_page() in split_huge_pages_all()
Date: Wed, 7 Sep 2022 13:57:45 -0700 [thread overview]
Message-ID: <20220907135745.cda0d84b5a3f9f6df39b9884@linux-foundation.org> (raw)
In-Reply-To: <20220907121157.GA2954283@ik1-406-35019.vs.sakura.ne.jp>
On Wed, 7 Sep 2022 21:11:57 +0900 Naoya Horiguchi <naoya.horiguchi@linux.dev> wrote:
>
> NULL pointer dereference is triggered when calling thp split via debugfs
> on the system with offlined memory blocks. With debug option enabled,
> the following kernel messages are printed out:
>
> page:00000000467f4890 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x121c000
> flags: 0x17fffc00000000(node=0|zone=2|lastcpupid=0x1ffff)
> raw: 0017fffc00000000 0000000000000000 dead000000000122 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> page dumped because: unmovable page
> page:000000007d7ab72e is uninitialized and poisoned
> page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
> ------------[ cut here ]------------
> kernel BUG at include/linux/mm.h:1248!
> invalid opcode: 0000 [#1] PREEMPT SMP PTI
> CPU: 16 PID: 20964 Comm: bash Tainted: G I 6.0.0-rc3-foll-numa+ #41
> ...
> RIP: 0010:split_huge_pages_write+0xcf4/0xe30
>
> This shows that page_to_nid() in page_zone() is unexpectedly called for an
> offlined memmap.
>
> Use pfn_to_online_page() to get struct page in PFN walker.
>
> Fixes: 49071d436b51 ("thp: add debugfs handle to split all huge pages")
January of 2016! Or was this a long-term bug which was recently
exposed by some other change?
next prev parent reply other threads:[~2022-09-07 20:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 10:08 [BUG report] kernel NULL pointer dereference in split_huge_page with offlined memory block Naoya Horiguchi
2022-09-07 10:23 ` David Hildenbrand
2022-09-07 10:26 ` David Hildenbrand
2022-09-07 12:11 ` [PATCH] mm/huge_memory: use pfn_to_online_page() in split_huge_pages_all() Naoya Horiguchi
2022-09-07 12:39 ` David Hildenbrand
2022-09-08 2:39 ` HORIGUCHI NAOYA(堀口 直也)
2022-09-07 17:10 ` Yang Shi
2022-09-07 17:32 ` Michal Hocko
2022-09-07 20:57 ` Andrew Morton [this message]
2022-09-08 2:47 ` HORIGUCHI NAOYA(堀口 直也)
2022-09-08 6:14 ` David Hildenbrand
2022-09-08 6:31 ` HORIGUCHI NAOYA(堀口 直也)
2022-09-08 2:19 ` Miaohe Lin
2022-09-08 3:06 ` HORIGUCHI NAOYA(堀口 直也)
2022-09-08 3:25 ` Miaohe Lin
2022-09-08 7:07 ` Michal Hocko
2022-09-09 0:27 ` Miaohe Lin
2022-09-09 9:03 ` David Hildenbrand
2022-09-08 3:28 ` Oscar Salvador
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