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Thu, 8 Jan 2026 09:50:39 +0800 (CST) Received: from dggpemf100008.china.huawei.com (unknown [7.185.36.138]) by mail.maildlp.com (Postfix) with ESMTPS id 6BEBF40565; Thu, 8 Jan 2026 09:53:56 +0800 (CST) Received: from [10.174.177.243] (10.174.177.243) by dggpemf100008.china.huawei.com (7.185.36.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 8 Jan 2026 09:53:53 +0800 Message-ID: <7b0330e8-e42d-4aa8-91ab-1098a9f89c7e@huawei.com> Date: Thu, 8 Jan 2026 09:53:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 mm-new 0/6] mm: hugetlb: allocate frozen gigantic folio From: Kefeng Wang To: Zi Yan , Mark Brown , Claudiu Beznea CC: Andrew Morton , David Hildenbrand , Oscar Salvador , Muchun Song , , , , Vlastimil Babka , Brendan Jackman , Johannes Weiner , Matthew Wilcox References: <20251230072422.265265-1-wangkefeng.wang@huawei.com> <4211be25-3fc0-4395-9b24-a5ff0b3caa34@tuxon.dev> <13ad5888-2d53-40c8-9269-22bc6001754a@sirena.org.uk> <7253A444-97D1-4256-9AD9-BCFF66437510@nvidia.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: kwepems200002.china.huawei.com (7.221.188.68) To dggpemf100008.china.huawei.com (7.185.36.138) X-Rspamd-Server: rspam02 X-Stat-Signature: 4bg7w4bp5g13gg675m57g38u37ibhyda X-Rspam-User: X-Rspamd-Queue-Id: AD4BA100005 X-HE-Tag: 1767837243-376135 X-HE-Meta: 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 oEz/lKxL MfaTLlF/LJneaGxi8fR4a6kJdqeCkASkajgWsqOzSYudlV5G014CbOD/adh5vbhyLau9m+3U2DWU0qHA+9oSo4oZmV0/ylIxQurBAIz0sYP1fjSJ+bM/Axgb91+LcjlfK6nQAoi/prt3jlyO+7Zw4DqwiAl5N1moIpGuhbwP2rhR6MvBHcEmYsrh2NwpkL4KqC2gnFGKtQDANdKl1xoz1rBsqepiaMJIOwkXwHcaSQcfI2fUJxyBL/FaAfxKEldhryO20gkIG2A1de3U52UDAxSRDhQ0+BPXPhSV5IflKfLZ0I/XxX92RNgFx17A/FSEVjUTpsFl3mO3KEPV8H+gqe5g8RibteF6jIR3aSVXEb3fhKMhHjjyKefXubnAeFiWnP7Bxi8zO8A1a+y61klrnKbh/Kw== 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 2026/1/8 9:05, Kefeng Wang wrote: > > > On 2026/1/8 3:38, Zi Yan wrote: >> On 7 Jan 2026, at 13:39, Mark Brown wrote: >> >>> On Wed, Jan 07, 2026 at 07:31:30PM +0200, Claudiu Beznea wrote: >>>> On 12/30/25 09:24, Kefeng Wang wrote: >>> >>>>> Introduce alloc_contig_frozen_pages() and cma_alloc_frozen_compound() >>>>> which avoid atomic operation about page refcount, and then convert to >>>>> allocate frozen gigantic folio by the new helpers in hugetlb to >>>>> cleanup >>>>> the alloc_gigantic_folio(). >>>> >>>> I'm seeing the following issues on the Renesas RZ/G3S SoC when doing >>>> suspend >>>> to idle: >>>> >>>> [  129.636729] Unable to handle kernel paging request at virtual >>>> address >>>> dead000000000108 >>>> [  129.644674] Mem abort info: >>>> [  129.647456]   ESR = 0x0000000096000044 >>> >>> This is also introducing OOMs when doing at least audio tests (I don't >>> think these are super relevant) on Raspberry Pi 3B+ running NFS root >>> (probably more relevant): >>> >>> [   64.064256] Unable to handle kernel paging request at virtual >>> address fffffdffc1000000 >>> >>> ... >>> >>> [   64.087583] Call trace: >>> [   64.087586]  kmem_cache_free+0x88/0x434 (P) >>> [   64.087598]  skb_free_head+0x9c/0xb8 >>> [   64.087608]  skb_release_data+0x120/0x174 >>> [   64.087615]  __kfree_skb+0x2c/0x44 >>> [   64.087622]  tcp_data_queue+0x948/0xe50 >>> >>> Full log: >>> >>>    https://lava.sirena.org.uk/scheduler/job/2341856#L1721 >>> >>> Bisection identifies: >>> >>> [fb9a328d30400dbc8b2ea5a57daeb28bedac398b] mm: cma: add >>> cma_alloc_frozen{_compound}() >>> >>> as being the comit that introduces the issue.  Bisect log with links to >>> further test runs: >> >> Hi Mark and Claudiu, > > Thanks for the reports. > >> >> Can you try the patch below to see if it fixes the issue? Basically, >> in cma_release(), count was used to drop page ref and decreased to 0, >> but after the loop, count becomes -1 and __cma_release_frozen() >> is releasing unnecessary pages. > > Oh，sorry for introducing the regression, my previous self-tests were > more focused on the hugetlb part, I should be more careful about this, > and thanks Zi Yan for the quick fix, I will do more check and test for > the non-hugetlb part. > > Based on the cma_debug interface, I performed quick tests to reproduce the issue before Zi's fix. With the fix applied, the crash was resolved, and no other issues were observed during testing.