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Shutemov" , Andrew Morton , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Daniel Axtens References: <20250409094043.1629234-1-kirill.shutemov@linux.intel.com> <00a37819-b2ae-4399-b21d-86339059c46a@redhat.com> <54aymye7ctvyoaxdoge3h756tnhd57kzy4lnpggvydohtrxy45@ruwh3ni4yttq> From: David Hildenbrand 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: <54aymye7ctvyoaxdoge3h756tnhd57kzy4lnpggvydohtrxy45@ruwh3ni4yttq> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: gWgq8ikFpI4C64PMeHxJ-eSxY88Y1iUiMVAOTZ4UfpI_1744194371 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 14CC04000A X-Rspamd-Server: rspam05 X-Rspam-User: X-Stat-Signature: gsqo63af6j79gd9fgfy4iwgsxut8i3q6 X-HE-Tag: 1744194373-739673 X-HE-Meta: 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 gH+IJDxg 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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 09.04.25 12:23, Kirill A. Shutemov wrote: > On Wed, Apr 09, 2025 at 11:52:43AM +0200, David Hildenbrand wrote: >> On 09.04.25 11:40, Kirill A. Shutemov wrote: >>> In the case of apply_to_existing_page_range(), apply_to_pte_range() is >>> reached with 'create' set to false. When !create, the loop over the PTE >>> page table is broken. >>> >>> apply_to_pte_range() will only move to the next PTE entry if 'create' is >>> true or if the current entry is not pte_none(). >>> >>> This means that the user of apply_to_existing_page_range() will not have >>> 'fn' called for any entries after the first pte_none() in the PTE page >>> table. >>> >>> Fix the loop logic in apply_to_pte_range(). >>> >>> Signed-off-by: Kirill A. Shutemov >>> Fixes: be1db4753ee6 ("mm/memory.c: add apply_to_existing_page_range() helper") >>> Cc: Daniel Axtens >>> --- >>> mm/memory.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/mm/memory.c b/mm/memory.c >>> index fb7b8dc75167..2094564f4dfb 100644 >>> --- a/mm/memory.c >>> +++ b/mm/memory.c >>> @@ -2907,11 +2907,11 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, >>> if (fn) { >>> do { >>> if (create || !pte_none(ptep_get(pte))) { >>> - err = fn(pte++, addr, data); >>> + err = fn(pte, addr, data); >>> if (err) >>> break; >>> } >>> - } while (addr += PAGE_SIZE, addr != end); >>> + } while (pte++, addr += PAGE_SIZE, addr != end); >>> } >>> *mask |= PGTBL_PTE_MODIFIED; >> >> LGTM. just curious, did you run into any actual issues that are worth >> describing? > > I stepped on it in my non-upstream code debugging. I am not sure how it > affects existing users. > >> It should affect apply_to_existing_page_range() users where create==false. >> There are not many, and likely most PTEs in the range they are passing are >> all non-none. > > Or we just silently leak memory :P That's exactly what I am trying to figure out: is there something upstream that could actually run into this such that we should CC stable? -- Cheers, David / dhildenb