From: Zi Yan <ziy@nvidia.com>
To: David Hildenbrand <davidhildenbrand@mailbox.org>
Cc: "David Hildenbrand (Arm)" <david@kernel.org>,
Ron Economos <re@w6rz.net>,
wangkefeng.wang@huawei.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
jackmanb@google.com, jane.chu@oracle.com, hannes@cmpxchg.org,
willy@infradead.org, muchun.song@linux.dev, osalvador@suse.de,
sidhartha.kumar@oracle.com, vbabka@suse.cz,
claudiu.beznea.uj@bp.renesas.com, Mark Brown <broonie@kernel.org>,
akpm@linux-foundation.org, pjw@kernel.org
Subject: Re: mm: Regression with v7.0-rc1 on RISC-V
Date: Tue, 24 Feb 2026 12:14:28 -0500 [thread overview]
Message-ID: <78D36EC1-2596-448A-A939-0A1AC7B3D1BC@nvidia.com> (raw)
In-Reply-To: <1966378802.577797.1771952827516@app.mailbox.org>
On 24 Feb 2026, at 12:07, David Hildenbrand wrote:
>> David Hildenbrand (Arm) <david@kernel.org> hat am 24.02.2026 12:00 CET geschrieben:
>>
>>
>>
>>
>>
>> On 2/24/26 09:37, Ron Economos wrote:
>>
>>> I'm getting a BUG dump during shutdown with Linux v7.0-rc1 on RISC-V.
>>>
>>>
>>>
>>> [ OK ] Reached target shutdown.target - System Shutdown.
>>>
>>> [ OK ] Reached target final.target - Late Shutdown Services.
>>>
>>> [ OK ] Finished systemd-reboot.service - System Reboot.
>>>
>>> [ OK ] Reached target reboot.target - System Reboot.
>>>
>>> [ 173.985249] BUG: Bad page state in process shutdown pfn:f8850
>>>
>>> [ 173.985311] page: refcount:1 mapcount:0 mapping:0000000000000000
>>>
>>> index:0x0 pfn:0xf8850
>>>
>>> [ 173.985336] flags: 0xffff80000000000(node=0|zone=0|
>>>
>>> lastcpupid=0x1ffff) CMA
>>>
>>> [ 173.985365] raw: 0ffff80000000000 ffffffc501e21448 ffffffc600f2ae88
>>>
>>> 0000000000000000
>>>
>>> [ 173.985386] raw: 0000000000000000 0000000000000000 00000001ffffffff
>>>
>>> 0000000000000000
>>>
>>> [ 173.985403] page dumped because: nonzero _refcount
>>
>> So, we're freeing something from CMA in cma_release().
>>
>>
>>
>> In cma_release() we iterate all pages to decrement their refcount
>>
>>
>>
>> VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn)));
>>
>>
>>
>> I would expect that this would fire already if there is still a page
>>
>> referenced.
>>
>>
>>
>> Are you running with CONFIG_DEBUG_VM=y ?
>>
>>
>>
>>
>>
>> --
>>
>> Cheers,
>>
>>
>>
>> David
>
> Thinking again without my computer at hand … isn‘t the call completely optimized out without CONFIG_DEBUG_VM?
>
>
>
> At least that’s what I remember.
Right. Without CONFIG_DEBUG_VM=y, VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn)))
and is_check_pages_enabled(), which leads to free_page_is_bad()’s
“page dumped because: nonzero _refcount”, are disabled.
It seems to me that someone else bump the page refcount between
VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn))) and free_page_is_bad().
Best Regards,
Yan, Zi
next prev parent reply other threads:[~2026-02-24 17:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-24 8:37 Ron Economos
2026-02-24 11:00 ` David Hildenbrand (Arm)
[not found] ` <1966378802.577797.1771952827516@app.mailbox.org>
2026-02-24 17:14 ` Zi Yan [this message]
2026-02-24 17:17 ` Zi Yan
2026-02-24 17:29 ` Zi Yan
2026-02-24 20:55 ` Ron Economos
2026-02-25 1:58 ` Kefeng Wang
2026-02-25 2:15 ` Zi Yan
2026-02-24 17:21 ` Mark Brown
2026-02-24 12:58 ` Kefeng Wang
2026-02-24 13:25 ` Ron Economos
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