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 53830F30951 for ; Thu, 5 Mar 2026 11:57:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA5276B00B5; Thu, 5 Mar 2026 06:57:20 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B79F16B00B7; Thu, 5 Mar 2026 06:57:20 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A93006B00B8; Thu, 5 Mar 2026 06:57:20 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 98FF16B00B5 for ; Thu, 5 Mar 2026 06:57:20 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 6198B1CE20 for ; Thu, 5 Mar 2026 11:57:20 +0000 (UTC) X-FDA: 84511859040.06.DF95DB6 Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) by imf28.hostedemail.com (Postfix) with ESMTP id BC03BC0006 for ; Thu, 5 Mar 2026 11:57:18 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=s3v1iK8W; spf=pass (imf28.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.189 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=1772711838; 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=MuGdh3NsMuiZscvyzRC4/MBSUBTvm1soytMKG+347XA=; b=cGiFAlhMRUgY0uxaQolF1E1OmELdzyig1Qm3r3DlN+gyr/6qcBQOGIXeRPRGtyI0cyUO6x iCMrQr5LCauJPdfediuSK7tAwh5ZUdEYMA/VIIg7A29vY2YFLBTAWSZugoKoPHmfoXDrCV fa0/AurSVA/z3nJrf0Ngk61JhyjR0HY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772711838; a=rsa-sha256; cv=none; b=vaDukQjqddTXIIktXpmVkBCbXpLbvpbk1cST+8fp3wSm01Fo3Rz8k4WjJftZ5JIjaZJWlw 4hejEl7XVJJvNMNGT4HZqFzO7YiOMk4pir/JK5Ivr5vKhti31dQ7KDv/cWPGs1Fad1cs80 NxCzIirq7P5Xb/y/4sK0bMXV/kUI0So= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=s3v1iK8W; spf=pass (imf28.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.189 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev 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=1772711836; 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=MuGdh3NsMuiZscvyzRC4/MBSUBTvm1soytMKG+347XA=; b=s3v1iK8W+2/lyiTlyMS3zxFj3WgIlRYhe5H+s0QFT0llX2t+stJ7v/BZUrvc7S0Nhlw+EV 9IpuZYgKVcG3RvQ0aect08xUayoWd8gLAKDQoOHod9upjfloUsBuJAYVVXJw8cV/URSRVE pdfe0Qfpo6AHi0UluFFEJceymQL/VzM= 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@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, yosry.ahmed@linux.dev, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, bhe@redhat.com, usamaarif642@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Qi Zheng Subject: [PATCH v6 18/33] mm: zswap: prevent memory cgroup release in zswap_compress() Date: Thu, 5 Mar 2026 19:52:36 +0800 Message-ID: <340f315050fb8a67caaf01b4836d4f38a41cf1a8.1772711148.git.zhengqi.arch@bytedance.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: BC03BC0006 X-Stat-Signature: mdcrzn67zxia8w8jbfydbbjtc1pj8fpw X-Rspam-User: X-HE-Tag: 1772711838-734143 X-HE-Meta: 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 /vMJezvt VrsjMtGBtpx6UxqnpsxxWuh9ECOmHAm2el7JP+UnYJ+mbwpUJ3EaiAln6/ysH6hbSEMUB1BnU5owy3dRlSy045xltT+r+hcuS+teH3viqSu0XyVjmSEM1wjasKb1LqB6YUnIG2zGOh3dOkIMl7JVnPgd00ZHeari0pYKh3c1P3F/DcQapwwpccagNlN2jQt7CiKyp5sjvOtVEc78SoJ5LrIMNFt9yAeE7WS9NXjVMafiUPIPYujIsrPk2GKCCugaKhVajC7QgeVbjDdFZIy0DKnnrvbIv1utl9CnROa6tliSKnsClc9eOd5dKPcPslyAclH2x 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 zswap_compress(). Signed-off-by: Qi Zheng Acked-by: Johannes Weiner Acked-by: Shakeel Butt Acked-by: Muchun Song Reviewed-by: Harry Yoo --- mm/zswap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/zswap.c b/mm/zswap.c index a399f7a108304..fb525874a1b6b 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -893,11 +893,14 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, * to the active LRU list in the case. */ if (comp_ret || !dlen || dlen >= PAGE_SIZE) { + rcu_read_lock(); if (!mem_cgroup_zswap_writeback_enabled( folio_memcg(page_folio(page)))) { + rcu_read_unlock(); comp_ret = comp_ret ? comp_ret : -EINVAL; goto unlock; } + rcu_read_unlock(); comp_ret = 0; dlen = PAGE_SIZE; dst = kmap_local_page(page); -- 2.20.1