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[2003:cb:c707:5c00:e650:bcd7:e2a0:54fe]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-428e6d6b942sm7860845e9.5.2024.08.01.13.24.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 01 Aug 2024 13:24:32 -0700 (PDT) Message-ID: Date: Thu, 1 Aug 2024 22:24:32 +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] mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory To: Miaohe Lin , Andrew Morton Cc: nao.horiguchi@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240712064249.3882707-1-linmiaohe@huawei.com> <20240712140921.9aa90b18d22e67417d59dfc1@linux-foundation.org> <8fe349f9-d3d3-65ab-6045-da0bd19249ea@huawei.com> <00e18339-d911-4332-8732-e31bcecbf823@redhat.com> <5f8107e2-2b37-d899-f7f2-5a6093d8b089@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 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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 19.07.24 05:55, Miaohe Lin wrote: > On 2024/7/18 13:15, David Hildenbrand wrote: >> On 18.07.24 05:04, Miaohe Lin wrote: >>> On 2024/7/17 17:01, David Hildenbrand wrote: >>>> On 16.07.24 04:34, Miaohe Lin wrote: >>>>> On 2024/7/16 0:16, David Hildenbrand wrote: >>>>>> On 15.07.24 08:23, Miaohe Lin wrote: >>>>>>> On 2024/7/13 5:09, Andrew Morton wrote: >>>>>>>> On Fri, 12 Jul 2024 14:42:49 +0800 Miaohe Lin wrote: >>>>>>>> >>>>>>>>> When I did memory failure tests recently, 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. >>>>>>>> >>>>>>>> I'm not seeing the call path.  Is this BUG happening via >>>>>>>> >>>>>>>> static __always_inline void __ClearPage##uname(struct page *page)    \ >>>>>>>> {                                    \ >>>>>>>>       VM_BUG_ON_PAGE(!Page##uname(page), page);            \ >>>>>>>>       page->page_type |= PG_##lname;                    \ >>>>>>>> } >>>>>>>> >>>>>>>> ? >>>>>>>> >>>>>>>> If so, where's the callsite? >>>>>>> >>>>>>> It is BUG on PF_ANY(): >>>>>>> >>>>>>> PAGEFLAG(HWPoison, hwpoison, PF_ANY) >>>>>>> >>>>>>> #define PF_ANY(page, enforce)    PF_POISONED_CHECK(page) >>>>>>> >>>>>>> #define PF_POISONED_CHECK(page) ({                    \ >>>>>>>       VM_BUG_ON_PGFLAGS(PagePoisoned(page), page);        \ >>>>>>>       page; }) >>>>>>> >>>>>>> #define    PAGE_POISON_PATTERN    -1l >>>>>>> static inline int PagePoisoned(const struct page *page) >>>>>>> { >>>>>>>       return READ_ONCE(page->flags) == PAGE_POISON_PATTERN; >>>>>>> } >>>>>>> >>>>>>> The offlined pages will have page->flags set to PAGE_POISON_PATTERN while pfn is still valid: >>>>>>> >>>>>>> offline_pages >>>>>>>      remove_pfn_range_from_zone >>>>>>>        page_init_poison >>>>>>>          memset(page, PAGE_POISON_PATTERN, size); >>>>>> >>>>>> Worth noting that this happens after __offline_isolated_pages() marked the covering sections as offline. >>>>>> >>>>>> Are we missing a pfn_to_online_page() check somewhere, or are we racing with offlining code that marks the section offline? >>>>> >>>>> I was thinking about to use pfn_to_online_page() instead of pfn_to_page() in unpoison_memory() so we can get rid of offlined pages. >>>>> But there're ZONE_DEVICE pages. They're not-onlined too. And unpoison_memory() should work for them. So we can't simply use >>>>> pfn_to_online_page() in that. Or am I miss something? >>>> >>>> Right, pfn_to_online_page() does not detect ZONE_DEVICE. That has to be handled separately if pfn_to_online_page() would fail. >>>> >>>> ... which is what we do in memory_failure(): >>>> >>>> p = pfn_to_online_page(pfn); >>>> if (!p) { >>>>      if (pfn_valid(pfn)) { >>>>          pgmap = get_dev_pagemap(pfn, NULL); >>>>          put_ref_page(pfn, flags); >>>>          if (pgmap) { >>>>              ... >>>>          } >>>>      } >>>>      ... >>>> } >>> >>> Yup, this will be a good alternative. But will it be better to simply check PagePoisoned() instead? >> >> The memmap of offline memory sections shall not be touched, so .... don't touch it ;) >> >> Especially because that PagePoisoned() check is non-sensical without poisoining-during-memmap-init. You would still work with memory in offline sections. >> >> I think the code is even wrong in that regard: we allow for memory offlining to work with HWPoisoned pages, see __offline_isolated_pages(). Staring at unpoison_memory(), we might be putting these pages back to the buddy? Which is completely wrong. > > I agree with you. Thanks for detailed explanation. :) > Thanks David. So ... I assume there will be a new patch? :) -- Cheers, David / dhildenb