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 6D5FEF30951 for ; Thu, 5 Mar 2026 11:56:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D748C6B00A9; Thu, 5 Mar 2026 06:56:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D3B506B00AB; Thu, 5 Mar 2026 06:56:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C37316B00AC; Thu, 5 Mar 2026 06:56:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id AD6F66B00A9 for ; Thu, 5 Mar 2026 06:56:15 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 518DA160903 for ; Thu, 5 Mar 2026 11:56:15 +0000 (UTC) X-FDA: 84511856310.15.37552EF Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) by imf27.hostedemail.com (Postfix) with ESMTP id 9583A4000B for ; Thu, 5 Mar 2026 11:56:13 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=vDIj4tca; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.183 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1772711773; 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=s82tZFT3iNsr3WMx/4d8Ml9gjp1Ep9qgTy0gWjRVe+I=; b=3x8VPZdROag7/efRddST9FRdHRV8zhMxryCOwEzYfNspKdbhu+rLF8tiue3pn0/0nu0a74 F3cNcjtbjJVxmHfyN3Ld07iJ7V4uv+CVdsqkQG/DmEuPZFNF+GAQen5ssxE9C4Y4soK8Pw w7d3J9gMT4TcWgncrd7HLciWmIRIqAU= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=vDIj4tca; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.183 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772711773; a=rsa-sha256; cv=none; b=kykmr//q3bOHDRa/2vU8lz6/YkT5KzYX+I2XwqE18UmmUrnavLFXhDzkzeS714XgoLAAlz 8zUuBh6VpQYZKnP3VXieRFE2LcCDdhaApuAV4O2W6bt0gn/OcvPaU0lglb9GuGzyJ3Ccf3 8qryRD96hvopZD2qcbUKQiEIx4xq6z0= 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=1772711771; 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=s82tZFT3iNsr3WMx/4d8Ml9gjp1Ep9qgTy0gWjRVe+I=; b=vDIj4tcaixUxSqZBHWF4+YL7Up0TeXQdEYFI7em4v5qbgKuDZOuC1XTD7ewfFUcwVeAIMm TLAowdrnhkx6Q49+Fxgbj2oZ6OvyEkZ/8UJC8z7FIaT5wLfoJvdSVUKOGiXIbMEmGgKLxN BNvDvDiql5zp4WavFRG9F9e4VcBmnVg= 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, Muchun Song , Qi Zheng Subject: [PATCH v6 12/33] mm: page_io: prevent memory cgroup release in page_io module Date: Thu, 5 Mar 2026 19:52:30 +0800 Message-ID: <7c3708358412fb02c482d0985feb5e9513a863ef.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: rspam04 X-Rspamd-Queue-Id: 9583A4000B X-Stat-Signature: ddxj6w3u57d896yk5q7u4bkpgjinn6q1 X-Rspam-User: X-HE-Tag: 1772711773-404306 X-HE-Meta: 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 GoYuobQI slXuQpKTCHXoipkDJpWqRWDh5FE34idl4g5SJoPrKBYPuldHGxtw+xTfKx/bXFiXsOsF1wwTVcGW47JMjUdWrCmNfTZ5ZfLuq6xuEmgxMEscNJoErRrGX8Qg0c51iRfjk1IPU66HdS1CxwCGW2108u+zPZtuIwopcH62tw4Yfuat6iq82RjuoDtQwmUX8Dx+QgsWLIH0EhUt55KN6R9k3GlKilE63o+jpm3mZGPWyigKIFA3/ijQWU8o//tBNFoX7aFBxu6nEXBXE6bQT9EbVb2193gZC5KNXlsJw+J2jUayBnPBtsn9OSYW4B0Q4Ahu2EvLp Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Muchun Song 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 swap_writeout() and bio_associate_blkg_from_page(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng Reviewed-by: Harry Yoo Acked-by: Johannes Weiner Acked-by: Shakeel Butt --- mm/page_io.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index a2c034660c805..63b262f4c5a9b 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -276,10 +276,14 @@ int swap_writeout(struct folio *folio, struct swap_iocb **swap_plug) count_mthp_stat(folio_order(folio), MTHP_STAT_ZSWPOUT); goto out_unlock; } + + rcu_read_lock(); if (!mem_cgroup_zswap_writeback_enabled(folio_memcg(folio))) { + rcu_read_unlock(); folio_mark_dirty(folio); return AOP_WRITEPAGE_ACTIVATE; } + rcu_read_unlock(); __swap_writepage(folio, swap_plug); return 0; @@ -307,11 +311,11 @@ static void bio_associate_blkg_from_page(struct bio *bio, struct folio *folio) struct cgroup_subsys_state *css; struct mem_cgroup *memcg; - memcg = folio_memcg(folio); - if (!memcg) + if (!folio_memcg_charged(folio)) return; rcu_read_lock(); + memcg = folio_memcg(folio); css = cgroup_e_css(memcg->css.cgroup, &io_cgrp_subsys); bio_associate_blkg_from_css(bio, css); rcu_read_unlock(); -- 2.20.1