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([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-afe6a3d7cd5sm566241666b.6.2025.08.26.03.58.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 26 Aug 2025 03:58:29 -0700 (PDT) Message-ID: <5eb5dbc1-274a-4932-8c77-8000509deadb@redhat.com> Date: Tue, 26 Aug 2025 12:58:28 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory To: Miaohe Lin , akpm@linux-foundation.org Cc: nao.horiguchi@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250826075710.278412-1-linmiaohe@huawei.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20250826075710.278412-1-linmiaohe@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 26.08.25 09:57, Miaohe Lin wrote: > When I did memory failure tests, below panic occurs: > > page dumped because: VM_BUG_ON_PAGE(PagePoisoned(page)) > kernel BUG at include/linux/page-flags.h:616! > Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI > CPU: 3 PID: 720 Comm: bash Not tainted 6.10.0-rc1-00195-g148743902568 #40 > RIP: 0010:unpoison_memory+0x2f3/0x590 > RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246 > RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8 > RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0 > RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb > R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000 > R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe > FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0 > Call Trace: > > unpoison_memory+0x2f3/0x590 > simple_attr_write_xsigned.constprop.0.isra.0+0xb3/0x110 > debugfs_attr_write+0x42/0x60 > full_proxy_write+0x5b/0x80 > vfs_write+0xd5/0x540 > ksys_write+0x64/0xe0 > do_syscall_64+0xb9/0x1d0 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f08f0314887 > RSP: 002b:00007ffece710078 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f08f0314887 > RDX: 0000000000000009 RSI: 0000564787a30410 RDI: 0000000000000001 > RBP: 0000564787a30410 R08: 000000000000fefe R09: 000000007fffffff > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009 > R13: 00007f08f041b780 R14: 00007f08f0417600 R15: 00007f08f0416a00 > > Modules linked in: hwpoison_inject > ---[ end trace 0000000000000000 ]--- > RIP: 0010:unpoison_memory+0x2f3/0x590 > RSP: 0018:ffffa57fc8787d60 EFLAGS: 00000246 > RAX: 0000000000000037 RBX: 0000000000000009 RCX: ffff9be25fcdc9c8 > RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff9be25fcdc9c0 > RBP: 0000000000300000 R08: ffffffffb4956f88 R09: 0000000000009ffb > R10: 0000000000000284 R11: ffffffffb4926fa0 R12: ffffe6b00c000000 > R13: ffff9bdb453dfd00 R14: 0000000000000000 R15: fffffffffffffffe > FS: 00007f08f04e4740(0000) GS:ffff9be25fcc0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000564787a30410 CR3: 000000010d4e2000 CR4: 00000000000006f0 > Kernel panic - not syncing: Fatal exception > Kernel Offset: 0x31c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) > ---[ end Kernel panic - not syncing: Fatal exception ]--- > > The root cause is that unpoison_memory() tries to check the PG_HWPoison > flags of an uninitialized page. So VM_BUG_ON_PAGE(PagePoisoned(page)) is > triggered. This can be reproduced by below steps: > 1.Offline memory block: > echo offline > /sys/devices/system/memory/memory12/state > 2.Get offlined memory pfn: > page-types -b n -rlN > 3.Write pfn to unpoison-pfn > echo > /sys/kernel/debug/hwpoison/unpoison-pfn > > This scene can be identified by pfn_to_online_page() returning NULL. > And ZONE_DEVICE pages are never expected, so we can simply fail if > pfn_to_online_page() == NULL to fix the bug. > > Suggested-by: David Hildenbrand > Signed-off-by: Miaohe Lin Similar to commit 96c804a6ae8c59a9092b3d5dd581198472063184 Author: David Hildenbrand Date: Fri Oct 18 20:19:23 2019 -0700 mm/memory-failure.c: don't access uninitialized memmaps in memory_failure() We should check for pfn_to_online_page() to not access uninitialized memmaps. Reshuffle the code so we don't have to duplicate the error message. Link: http://lkml.kernel.org/r/20191009142435.3975-3-david@redhat.com Signed-off-by: David Hildenbrand Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Acked-by: Naoya Horiguchi Cc: Michal Hocko Cc: [4.13+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds We should likely just use the exact same Fixes: Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Not sure about CCing stable. This is a pure debugging feature (depends on DEBUG_KERNEL), and someone really has to trigger it manually to provoke this. So I would not CC stable. > --- > v2: > Use pfn_to_online_page per David. Thanks. > v3: > Simply fail if pfn_to_online_page() == NULL per David. Thanks. > --- > mm/memory-failure.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index c15ffee7d32b..212620308028 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -2572,7 +2572,9 @@ int unpoison_memory(unsigned long pfn) > if (!pfn_valid(pfn)) > return -ENXIO; > > - p = pfn_to_page(pfn); > + p = pfn_to_online_page(pfn); > + if (!p) > + return -EIO; I think we can just drop the pfn_valid() check now. pfn_to_online_page() implies a pfn_valid() check. -- Cheers David / dhildenb