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[149.14.88.26]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-607f2a0251dsm3884362a12.45.2025.06.11.02.24.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Jun 2025 02:24:44 -0700 (PDT) Message-ID: <62e1f100-0e0e-40bc-9dc3-fcaf8f8d343f@redhat.com> Date: Wed, 11 Jun 2025 11:24:43 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list From: David Hildenbrand To: Jinjiang Tu , akpm@linux-foundation.org, linmiaohe@huawei.com Cc: linux-mm@kvack.org, wangkefeng.wang@huawei.com, Zi Yan References: <20250611074643.250837-1-tujinjiang@huawei.com> <1f0c7d73-b7e2-4ee9-8050-f23c05e75e8b@redhat.com> 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: _-C7sK7AMg3gLqjHca8MAxq92XJlf0dK5LqZLru5U0E_1749633897 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: ADA081C0009 X-Stat-Signature: o8xhe7fkdug1oge6k413ckx61eayc3o6 X-HE-Tag: 1749633900-628987 X-HE-Meta: U2FsdGVkX18C44M1w+V0ZvMlbmtJlbDE0KZ1zrbHTM1v/V3ZHSBdsYdewC16eL7AmK5ojUOxJ5wALfBE6zKty8GDWF5Y4QFMCYCpn+NC2/psyEENP8xqLZi8le3bkDdB6CHMxYAH3qtYOto4DZR62AEcGQ5TWhIkZiOPNm9dkwJWcUEa5/F9PUYDZpt8xVI6I3yFAMFRcwwRNx7uZSJCpPHxAjxZuju9WSDmmyS3ol9Gm97AyNh4xmc5RNa9ZVezziFLDYaP7sg0RsBPTLoXIzXgPbYWbMmXBHxzDk+G5tKYFfK4zPKSO5c2cEzF7t5mziDYIxn0Kv5LCBWfYy8vGAMOyu3y2PCHqSgBmLLuWCrg0/la/SfamXUlQfVkXpmD39nP3oW2/sYpcq3ieABPWZOb6TOWyFVdJSUK4EtmC/2JKneRYhD9JTlPcZsO/EQZlpaQBIUe/Oz/Y8KwpM99A8Wk30oeeX6o2ZXZuBAiOFFmfydQbprCEWpTEMkjry9wvv0dO+SfsIMU+87XAQCNb7jU+lAag+eoBPudvh9NmFanovk8VZcEX3Jiaid6ciIAUW/GjGzgRW3LI0lTvwsmE/8bxYLQE6PfC0rwLyfHfwBZB/GogM+wx585FpTPaYwg05x3DkvuPNNUDoWLodkCKhGMzVteByZfPfDad0XnCdD5jGj3Z0F6AvDFu6h2s+AYbxWYbQj+k1+SRem7RQ2BQ+kuEHP7MZl+QcJuAjex8jvRoC48ZbGo2cqUjfe8v5H+H8Mq71QqggqNTNAWCP2ee53LkbW45nt6LH3RpNThpAKv7Hu/KMgzp4Yx3yciwjnCeg4LwnTilQeqSV0vCsZuavLGSsm4pQF73u3Ukp70IvHn+xnOI6F7GgSHUbhcK9Cerz6mYUQ2WjO42ILmwf8qZkUm7I1fLM2Tp1oLQbz8bj246SrCLEBgnV+sWHPY28ITb7Szye6yiKmmK+DuSB3 AqN+lLgm 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 11.06.25 11:20, David Hildenbrand wrote: > On 11.06.25 11:00, Jinjiang Tu wrote: >> >> 在 2025/6/11 16:35, David Hildenbrand 写道: >>> On 11.06.25 10:29, Jinjiang Tu wrote: >>>> >>>> 在 2025/6/11 15:59, David Hildenbrand 写道: >>>>> On 11.06.25 09:46, Jinjiang Tu wrote: >>>>>> In shrink_folio_list(), the hwpoisoned folio may be large folio, which >>>>>> can't be handled by unmap_poisoned_folio(). >>>>>> >>>>>> Since UCE is rare in real world, and race with reclaimation is more >>>>>> rare, >>>>>> just skipping the hwpoisoned large folio is enough. memory_failure() >>>>>> will >>>>>> handle it if the UCE is triggered again. >>>>>> >>>>>> Fixes: 1b0449544c64 ("mm/vmscan: don't try to reclaim hwpoison folio") >>>>> >>>>> Please also add >>>>> >>>>> Closes: >>>>> >>>>> with a link to the report >>>> Thanks, I will add it. >>>>> >>>>>> Reported-by: syzbot+3b220254df55d8ca8a61@syzkaller.appspotmail.com >>>>>> Signed-off-by: Jinjiang Tu >>>>>> --- >>>>>>    mm/vmscan.c | 8 ++++++++ >>>>>>    1 file changed, 8 insertions(+) >>>>>> /home/tujinjiang/hulk-repo/hulk/mm/mempolicy.c >>>>>> diff --git a/mm/vmscan.c b/mm/vmscan.c >>>>>> index b6f4db6c240f..3a4e8d7419ae 100644 >>>>>> --- a/mm/vmscan.c >>>>>> +++ b/mm/vmscan.c >>>>>> @@ -1131,6 +1131,14 @@ static unsigned int shrink_folio_list(struct >>>>>> list_head *folio_list, >>>>>>                goto keep; >>>>>>              if (folio_contain_hwpoisoned_page(folio)) { >>>>>> +            /* >>>>>> +             * unmap_poisoned_folio() can't handle large >>>>>> +             * folio, just skip it. memory_failure() will >>>>>> +             * handle it if the UCE is triggered again. >>>>>> +             */ >>>>>> +            if (folio_test_large(folio)) >>>>>> +                goto keep_locked; >>>>>> + >>>>>>                unmap_poisoned_folio(folio, folio_pfn(folio), false); >>>>>>                folio_unlock(folio); >>>>>>                folio_put(folio); >>>>> >>>>> Why not handle that in unmap_poisoned_folio() to make that limitation >>>>> clear and avoid? >>>> I tried to put the check in unmap_poisoned_folio(), but it still exists >>>> other issues. >>> >>> >>> >>>> The calltrace in v6.6 kernel: >>>> >>>> Unable to handle kernel paging request at virtual address >>>> fbd5200000000024 >>>> KASAN: maybe wild-memory-access in range >>>> [0xdead000000000120-0xdead000000000127] >>>> pc : __list_add_valid_or_report+0x50/0x158 lib/list_debug.c:32 >>>> lr : __list_add_valid include/linux/list.h:88 [inline] >>>> lr : __list_add include/linux/list.h:150 [inline] >>>> lr : list_add_tail include/linux/list.h:183 [inline] >>>> lr : lru_add_page_tail.constprop.0+0x4ac/0x640 mm/huge_memory.c:3187 >>>> Call trace: >>>>    __list_add_valid_or_report+0x50/0x158 lib/list_debug.c:32 >>>>    __list_add_valid include/linux/list.h:88 [inline] >>>>    __list_add include/linux/list.h:150 [inline] >>>>    list_add_tail include/linux/list.h:183 [inline] >>>>    lru_add_page_tail.constprop.0+0x4ac/0x640 mm/huge_memory.c:3187 >>>>    __split_huge_page_tail.isra.0+0x344/0x508 mm/huge_memory.c:3286 >>>>    __split_huge_page+0x244/0x1270 mm/huge_memory.c:3317 >>>>    split_huge_page_to_list_to_order+0x1038/0x1620 mm/huge_memory.c:3625 >>>>    split_folio_to_list_to_order include/linux/huge_mm.h:638 [inline] >>>>    split_folio_to_order include/linux/huge_mm.h:643 [inline] >>>>    deferred_split_scan+0x5f8/0xb70 mm/huge_memory.c:3778 >>>>    do_shrink_slab+0x2a0/0x828 mm/vmscan.c:927 >>>>    shrink_slab_memcg+0x2c0/0x558 mm/vmscan.c:996 >>>>    shrink_slab+0x228/0x250 mm/vmscan.c:1075 >>>>    shrink_node_memcgs+0x34c/0x6a0 mm/vmscan.c:6630 >>>>    shrink_node+0x21c/0x1378 mm/vmscan.c:6664 >>>>    shrink_zones.constprop.0+0x24c/0xab0 mm/vmscan.c:6906 >>>>    do_try_to_free_pages+0x150/0x880 mm/vmscan.c:6968 >>>> >>>> >>>> The folio is deleted from lru and the folio->lru can't be accessed. If >>>> the folio is splitted later, >>>> lru_add_split_folio() assumes the folio is on lru. >>> >>> Not sure if something like the following would be appropriate: >>> >>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >>> index b91a33fb6c694..fdd58c8ba5254 100644 >>> --- a/mm/memory-failure.c >>> +++ b/mm/memory-failure.c >>> @@ -1566,6 +1566,9 @@ int unmap_poisoned_folio(struct folio *folio, >>> unsigned long pfn, bool must_kill) >>>         enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC | TTU_HWPOISON; >>>         struct address_space *mapping; >>> >>> +       if (folio_test_large && !folio_test_hugetlb(folio)) >>> +               return -EBUSY; >>> + >>>         if (folio_test_swapcache(folio)) { >>>                 pr_err("%#lx: keeping poisoned page in swap cache\n", >>> pfn); >>>                 ttu &= ~TTU_HWPOISON; >>> diff --git a/mm/vmscan.c b/mm/vmscan.c >>> index f8dfd2864bbf4..6a3426bc9e9d7 100644 >>> --- a/mm/vmscan.c >>> +++ b/mm/vmscan.c >>> @@ -1138,7 +1138,8 @@ static unsigned int shrink_folio_list(struct >>> list_head *folio_list, >>>                         goto keep; >>> >>>                 if (folio_contain_hwpoisoned_page(folio)) { >>> -                       unmap_poisoned_folio(folio, folio_pfn(folio), >>> false); >>> +                       if (unmap_poisoned_folio(folio, >>> folio_pfn(folio), false)){ >>> +                               list_add(&folio->lru, &ret_folios); >>>                         folio_unlock(folio); >>>                         folio_put(folio); >>>                         continue; >> >> The expected behaviour is keeping the folio on lru if >> unmap_poisoned_folio fails? > > Good question, it's a mess. > > If we keep the LRU bit cleared (kept isolated), we wouldn't have to add > it to the list. > > But now I wonder where deferred_split_scan() would check for the LRU flag? > > It seems to trylock, to then call split_folio(). > > In __folio_split(), I don't find any checks for the lru flag ... :( > > We call lru_add_split_folio() where we > VM_BUG_ON_FOLIO(folio_test_lru(new_folio), folio); Oh, that's for the new folio. So the checks in the other two paths apply. When we come through deferred, we don't expect a "list" and consequently assume that it is still on the LRU. VM_WARN_ON(!folio_test_lru(folio)); So not adding it back to the LRU will be problematic for lru_add_split_folio() when called through deferred shrinking I guess ... -- Cheers, David / dhildenb