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b=bwIg7by14/5Ml7GW5fG35Fybc0TWws4oWZAyqe1+hYdj4ZFel58Ezue5rsG8gjtAC Yg6gNAhYGp2wPP41LGs3qtEBF/Vk4AvoLjtLfxWmrE4gTF5kA9r/c6K3YxArzWAQrL BxxSdp9ycAwcg1Qu7kwPB0f9yLdLy4t8CnqCepfaHToGgZAD51vpW0ekyCw2QANT3+ rybJCFWvfrIPw52F/oB1oSnhR+HsyAdjPe77nDzKwIkW9QkEn9IZH7eTaRf+WWxujU 7x2pOm7B3QudTSqhVH5AB+Ed/bkj4rpTvlQ45FdazcS0AvKpf4q1pLg7AOdePTHnlA 5CF0w2qRGr05Q== Message-ID: Date: Tue, 3 Mar 2026 10:04:26 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] mm/mempolicy: possible double-unlock in migrate_to_node() on 6.6 To: Matthew Wilcox , "liying3@sungrowpower.com" Cc: akpm , linux-mm , linux-kernel , victor7q , Greg Kroah-Hartman References: <2026030310525141773825@sungrowpower.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 7A42F40013 X-Stat-Signature: qguo13pomi4nyezn86ed8ozx81zh4h43 X-Rspam-User: X-HE-Tag: 1772528671-753087 X-HE-Meta: U2FsdGVkX18inBmEF4+v6QI5rOkGGsbwQuqeX/UD6MA7n7HVb8NyESJP/qQKp9+aasznFT3JBVswifWP34HvmplQ6CnjRzZwLkcIjR95NY5p21qh00Dfay6hM3eCshgVvEbsBMBJKo/Xa3bveBUP56VuFk3jecKO7z5spCbd+6YujoK45DeR1FptPNhSZMOaGKhSkaF2XmtR0MjE29805HMfmBBV4Xk5uNoNchWNKmFBPEfyMOjGz+qKAW8BYggC6/1GERmFgroSEE2X5uN71pEn3M7u/KS0mf518Y+B3l/o/rNEZpb/JcrWXj0wvQDO4cK2HLsFX3/tmRnZUlpJvA+G3bX/k8vDGOy9qb5axCEuTFVFA8q0XvGujlYdPwLQqgW1QqTAeoYbkDPYi84Va1DrFzfqfFo9YKU9yCXxw5pwlFGaNUweckwu0A08CK81iRiqb1bBqFABvN2m7Xd5vXKwgN/kBE+f40U94AmAXqHthaoblzRxwGKBvYA0Tw61nyBcBZjCm1XZd1f4jjdNjFGes+ZIxGPzyoR2uaYTTC5qjd0/tkoG7otWZ0jqbdoIXlRrEk17RfpZbodWFWUd3nOeXTIYPNGX65CV+PXbC0uQTIBJD6m+tq3qGrP4Z3x1eBrJkaDgwzDyDFw8QDKyci2ML85NZjCn3PgqM6aW2bTx//nb6CcxAP+zTWdmmwdqcW82gx+JxzEBtnDYu5EY/Fd0Z1gbiVxci/r6p1hnSql3j5uoVL4wifNkXehq7BZf4fxZmkMsn/UJedzgDiyfbKV8hhw/JLwhnRa9/5y9kgSAaEpFDF2JJTSheEHdAY2vuzu2wAU17DSPjvxr2Pg2WeR0+Z7b2wo52nZ+tXzmeAmVsSRQIggIb5V2OCawM3u9pX/1MjGe01qooFkdO654Oxm5cY5sZfVugmx3ssgGD7+7+H97V9KcXJUE33xHZjzL0O/w5s5G6OvBekhiRQv 3FrV8C3G w1l8KYbWyNlfAxwhmKf29u9JT56TI6JGuedDoZpfSYmBtDdaNUM5zP+M7WAviKN5C4FIzOV3cw6AuBmeK/NqVPJT8SDVJeuneyPHso8lukLcS8XO23nj4T7mcgvlNMHjmnVR/CMoeMhNBwHnNaVfVfVE985NQPQNqnOUCQRa9O/aM2rI76RK/TGFdzWJoEF/ao9QcP/eqfCFVw69KypsZT4akDbtmAlxkmOLViTZ1n5VeduMGqBUdLga8TTYlww8jyXyZU1bc0SKDZ0NskjuiBnD+8VYJPlo/9TFtvrh3c0fezHCVTGHrw2U2Ev5v+O10yS9UzCdDP86o8n0aha22tkArqNGIZM4fbhd/gNP+b8oFbO5yltLEe8ofBY0jhBZW5iL2nTlO7KUfADg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/3/26 05:15, Matthew Wilcox wrote: > On Tue, Mar 03, 2026 at 10:52:51AM +0800, liying3@sungrowpower.com wrote: >> Hi Andrew, >> >> I found that a fix is required for this submission in branch 6.6. >> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a13b2b9b0b0b04612c7d81e3b3dfb485c5f7abc3 > > Agreed, although your email should more properly have been directed to > David and possibly Greg. Are you going to submit a patch to fix this, > or do you prefer that somebody else does it? > >> Regarding the difference between branches 6.6 and 6.12, in branch 6.6, mmap_read_lock() and mmap_read_unlock() are called outside the migrate_to_node() function. >> Therefore, mmap_read_unlock(mm) should not be invoked inside migrate_to_node(); otherwise, it would result in a double unlock of the mm. >> diff --git a/mm/mempolicy.c b/mm/mempolicy.c >> index 54f1b78d1b2c0f..94c74c594d102a 100644 >> --- a/mm/mempolicy.c >> +++ b/mm/mempolicy.c >> @@ -1071,6 +1071,10 @@ static long migrate_to_node(struct mm_struct *mm, int source, int dest, >> VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))); >> vma = find_vma(mm, 0); >> + if (unlikely(!vma)) { >> + mmap_read_unlock(mm); // this line should be deleted >> + return 0; >> + } Right, that unlock must go. Let me know if I should prepare a fix. -- Cheers, David