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[2003:cb:c734:9600:af27:4326:a216:2bfb]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43b73703f83sm162538005e9.13.2025.03.03.05.48.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 Mar 2025 05:48:35 -0800 (PST) Message-ID: <6bcf390b-3a10-4622-b573-de88e69ed1a6@redhat.com> Date: Mon, 3 Mar 2025 14:48:34 +0100 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 v2] mm/page_alloc: Add lockdep assertion for pageblock type change From: David Hildenbrand To: Brendan Jackman , Andrew Morton , Oscar Salvador Cc: Johannes Weiner , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250303-pageblock-lockdep-v2-1-3fc0c37e9532@google.com> <4d0f0bca-3096-4fb4-9e8b-d4dcdf7eeb92@redhat.com> 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: <4d0f0bca-3096-4fb4-9e8b-d4dcdf7eeb92@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 03.03.25 14:11, David Hildenbrand wrote: > On 03.03.25 13:13, Brendan Jackman wrote: >> Since the migratetype hygiene patches [0], the locking here is >> a bit more formalised. >> >> For other stuff, it's pretty obvious that it would be protected by the >> zone lock. But it didn't seem totally self-evident that it should >> protect the pageblock type. So it seems particularly helpful to have it >> written in the code. > > [...] > >> + >> u64 max_mem_size = U64_MAX; >> >> /* add this memory to iomem resource */ >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 579789600a3c7bfb7b0d847d51af702a9d4b139a..1ed21179676d05c66f77f9dbebf88e36bbe402e9 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -417,6 +417,10 @@ void set_pfnblock_flags_mask(struct page *page, unsigned long flags, >> >> void set_pageblock_migratetype(struct page *page, int migratetype) >> { >> + lockdep_assert_once(system_state == SYSTEM_BOOTING || >> + in_mem_hotplug() || >> + lockdep_is_held(&page_zone(page)->lock)); >> + > > I assume the call chain on the memory hotplug path is mostly > > move_pfn_range_to_zone()->memmap_init_range()->set_pageblock_migratetype() > > either when onlining a memory block, or from pagemap_range() while > holding the hotplug lock. > > But there is also the > memmap_init_zone_device()->memmap_init_compound()->__init_zone_device_page()->set_pageblock_migratetype() > one, called from pagemap_range() *without* holding the hotplug lock, and > you assertion would be missing that. Heh, and I even ran into that right now by accident during boot: [ 9.790696][ T1] WARNING: CPU: 3 PID: 1 at mm/page_alloc.c:420 set_pageblock_migratetype+0xb3/0xf0 [ 9.792672][ T1] Modules linked in: [ 9.793496][ T1] CPU: 3 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.14.0-rc3-00349-geaddff2b220c #164 [ 9.795511][ T1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 [ 9.797471][ T1] RIP: 0010:set_pageblock_migratetype+0xb3/0xf0 [ 9.798794][ T1] Code: 2c c5 c0 0b 6d 91 73 43 4d 69 e4 40 07 00 00 be ff ff ff ff 4b 8d bc 25 18 06 00 00 e8 46 09 1b 04 85 c0 0f 85 71 ff ff ff 90 <0f> 0b 90 e9 68 ff ff ff 31 db e9 74 ff ff ff 48 c7 c6 58 4a f7 86 [ 9.802906][ T1] RSP: 0018:ffffc9000013bcc0 EFLAGS: 00010246 [ 9.804198][ T1] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001 [ 9.805860][ T1] RDX: 0000000000000046 RSI: ffffffff8725b542 RDI: ffffffff872bd087 [ 9.807528][ T1] RBP: ffffeaffffc00000 R08: 0000000000000005 R09: 0000000000000000 [ 9.809186][ T1] R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000001d00 [ 9.810871][ T1] R13: ffff88847fffa540 R14: 0000000000000000 R15: 0000000000000000 [ 9.812526][ T1] FS: 0000000000000000(0000) GS:ffff88846fcc0000(0000) knlGS:0000000000000000 [ 9.814388][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9.815751][ T1] CR2: 0000000000000000 CR3: 00000000076d8000 CR4: 0000000000750ef0 [ 9.817410][ T1] PKRU: 55555554 [ 9.818143][ T1] Call Trace: [ 9.818821][ T1] [ 9.819428][ T1] ? set_pageblock_migratetype+0xb3/0xf0 [ 9.820639][ T1] ? __warn.cold+0x110/0x210 [ 9.821618][ T1] ? set_pageblock_migratetype+0xb3/0xf0 [ 9.822809][ T1] ? report_bug+0x1b9/0x320 [ 9.823762][ T1] ? handle_bug+0x54/0x90 [ 9.824675][ T1] ? exc_invalid_op+0x17/0x50 [ 9.825659][ T1] ? asm_exc_invalid_op+0x1a/0x20 [ 9.826727][ T1] ? set_pageblock_migratetype+0xb3/0xf0 [ 9.827914][ T1] __init_zone_device_page.constprop.0+0x20c/0x240 [ 9.829293][ T1] memmap_init_zone_device+0x191/0x330 [ 9.830478][ T1] memremap_pages+0x4b7/0xc80 [ 9.831485][ T1] dmirror_allocate_chunk+0x12b/0x400 [ 9.832628][ T1] hmm_dmirror_init+0x18f/0x260 [ 9.833657][ T1] ? __pfx_hmm_dmirror_init+0x10/0x10 [ 9.834798][ T1] do_one_initcall+0xa5/0x490 [ 9.835789][ T1] kernel_init_freeable+0x3b4/0x410 [ 9.836897][ T1] ? __pfx_kernel_init+0x10/0x10 [ 9.837938][ T1] kernel_init+0x1b/0x1d0 [ 9.838856][ T1] ret_from_fork+0x48/0x60 [ 9.839796][ T1] ? __pfx_kernel_init+0x10/0x10 [ 9.840864][ T1] ret_from_fork_asm+0x1a/0x30 [ 9.841878][ T1] -- Cheers, David / dhildenb