From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E1CBDCCF9E0 for ; Tue, 28 Oct 2025 14:04:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 460EA8015C; Tue, 28 Oct 2025 10:04:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 411638013F; Tue, 28 Oct 2025 10:04:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 300B08015C; Tue, 28 Oct 2025 10:04:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 1C58C8013F for ; Tue, 28 Oct 2025 10:04:02 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id D808B485CD for ; Tue, 28 Oct 2025 14:04:01 +0000 (UTC) X-FDA: 84047691882.15.B57DE5F Received: from out-180.mta0.migadu.com (out-180.mta0.migadu.com [91.218.175.180]) by imf08.hostedemail.com (Postfix) with ESMTP id 2AC8116001D for ; Tue, 28 Oct 2025 14:03:59 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Qdyjhz16; spf=pass (imf08.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.180 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761660240; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=H+7NrfaZDIPUuVApNFCo2ZEP+9yr6hXQlGbR4tT0+ik=; b=XMKOzBF7HqEcdpry1dd1AnX3PgNsmlXvymZi//EGnOHNdukSHb3ql5YvBayLD+/b54Ob4l AHb+WY9iIEzLTlpTJU0GGuo15tE0/cwsLJgXnBqMz1s9NkIWG4TEf7lJjpmUokHVIEdcB3 KaiermyAc93DWpJu23DS+1d/Fpo/VDM= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Qdyjhz16; spf=pass (imf08.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.180 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761660240; a=rsa-sha256; cv=none; b=pwHy9Yn15z9WhTKuyA7QG1cnQ4CshLEIRTVKlN3FxteclgwrrMm/zZxPmf9/W+39yBWs3u bKocR/Mp1mJyLWE+IZXuZKvkK82NCn0/u3tWmrStHOeEgpo9d3Fv0C4OrkiJTW31xKdXSR HjaxzlXFdZd1/i0vp+2seLwAYejfRWo= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1761660238; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=H+7NrfaZDIPUuVApNFCo2ZEP+9yr6hXQlGbR4tT0+ik=; b=Qdyjhz16yrrQUs+gx1nzi89faKxHADcP4j9vTU0L4BargQ0ss1oUx66KBzo6X3MeKKARg+ i7TdrDOyRKnHNz6X7Ryn/w5Lf8VqKa61i19yefLGT69//fwtHrH24n4kSvJiW1mDdOEeSP 2QfnOZ1TikLPFn1LqXa/r/dZnOq6tdw= From: Qi Zheng To: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@redhat.com, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Qi Zheng Subject: [PATCH v1 16/26] mm: thp: prevent memory cgroup release in folio_split_queue_lock{_irqsave}() Date: Tue, 28 Oct 2025 21:58:29 +0800 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: 4z5aba4cgfoj3dzyyu6ozcdpptdnfjdj X-Rspamd-Queue-Id: 2AC8116001D X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1761660239-223777 X-HE-Meta: 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 5IgvgUB6 1HI0Ud/YxSSFAzW3ePMYszBWD6kovvq0UHK2Edv7jLMaD2oKz8tWt/9596u/iG3J7X59WDMm6DdbQkFLOhymU2amJdAU+zStOPBs2WrXlpqG7oH3/hXVEoVk7ZlpTDUnuyLh1E4SJ5YbPDX7xIFQK+jN4QN1Al6vD1HkWWdX6MN/KPqiKshuM0iz2fzbNTv8B42EFJ1SITDBwE+ojUkdafVUZlzNzEWuijKq8ni3KnFT1BYYPXdwq+lrs6gqkQv6MZ0iIfUyt+B6YvM4= 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: From: Qi Zheng In the near future, a folio will no longer pin its corresponding memory cgroup. To ensure safety, it will only be appropriate to hold the rcu read lock or acquire a reference to the memory cgroup returned by folio_memcg(), thereby preventing it from being released. In the current patch, the rcu read lock is employed to safeguard against the release of the memory cgroup in folio_split_queue_lock{_irqsave}(). Signed-off-by: Qi Zheng --- mm/huge_memory.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9d3594df6eedf..067259a9e0809 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1153,13 +1153,25 @@ split_queue_lock_irqsave(int nid, struct mem_cgroup *memcg, unsigned long *flags static struct deferred_split *folio_split_queue_lock(struct folio *folio) { - return split_queue_lock(folio_nid(folio), folio_memcg(folio)); + struct deferred_split *queue; + + rcu_read_lock(); + queue = split_queue_lock(folio_nid(folio), folio_memcg(folio)); + rcu_read_unlock(); + + return queue; } static struct deferred_split * folio_split_queue_lock_irqsave(struct folio *folio, unsigned long *flags) { - return split_queue_lock_irqsave(folio_nid(folio), folio_memcg(folio), flags); + struct deferred_split *queue; + + rcu_read_lock(); + queue = split_queue_lock_irqsave(folio_nid(folio), folio_memcg(folio), flags); + rcu_read_unlock(); + + return queue; } static inline void split_queue_unlock(struct deferred_split *queue) -- 2.20.1