From nobody Thu Feb 12 10:55:43 2026 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 87F7B13D273 for ; Thu, 13 Jun 2024 08:21:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.132 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718266899; cv=none; b=vE+0KHgFFYIzXa87Tv38KOl/b0WUQTN+gKozy1ChMDvDYZEuhdu6OknKyoogbRlYoOhhrwHDlxFU61VJBdEPYKeo5oXUtPjFuO7G5pXv9fKvm0DZdYATvPsiDAmYSEk1W85uPvNzpJc4nRR/JK+n9TtewRtMA2tNH9+eKpeuYM4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718266899; c=relaxed/simple; bh=rrXcE+O9VN4XI0wCp0Jqru/S9cQsl0yPrjLzUve4IeU=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=tWh15gRy9c7y64XKPA9oTIvs+FAjkmFRzGLkVM38pxA4YPm0GP80JwzCrkoqLmEeqoXnO8He1gELZ7a3tGs680MRxRT+T8cGQj1ukyAYRD/fZJh8GMrQwNITcf0IYDflB4OHW8Nd7W4u64D244RUgsKvAkfKuzMtmGJ/P6eXkEQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=x97J06L5; arc=none smtp.client-ip=115.124.30.132 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="x97J06L5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1718266887; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=0QrNpcoNy4k31Qxi3z0ZW2oJXA9rvfY0thkoxU4Y00M=; b=x97J06L5rUOfMEXaIn8DKz60p5ZhveRfjlSeBDLCikNDLvOgdmta0rAEnmA5Wubb8AiEng8bbmtpGWc3PmdrIKjPjHAbMSgMG955mvlYJ7xo9myVOUDYh1z5BOPwko2kvXJXstsCfQBOZMOkaOArHuxHPlAH5mxD9ZnFVInnruw= X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R711e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037067110;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0W8NU4tU_1718266886; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W8NU4tU_1718266886) by smtp.aliyun-inc.com; Thu, 13 Jun 2024 16:21:27 +0800 From: Baolin Wang To: akpm@linux-foundation.org, hughd@google.com Cc: hannes@cmpxchg.org, nphamcs@gmail.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm: shmem: fix getting incorrect lruvec when replacing a shmem folio Date: Thu, 13 Jun 2024 16:21:19 +0800 Message-Id: <3c11000dd6c1df83015a8321a859e9775ebbc23e.1718266112.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 2.39.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When testing shmem swapin, I encountered the warning below on my machine. The reason is that replacing an old shmem folio with a new one causes mem_cgroup_migrate() to clear the old folio's memcg data. As a result, the old folio cannot get the correct memcg's lruvec needed to remove itself from the LRU list when it is being freed. This could lead to possible serio= us problems, such as LRU list crashes due to holding the wrong LRU lock, and incorrect LRU statistics. To fix this issue, we can fallback to use the mem_cgroup_replace_folio() to replace the old shmem folio. [ 5241.100311] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0= x0 pfn:0x5d9960 [ 5241.100317] head: order:4 mapcount:0 entire_mapcount:0 nr_pages_mapped:0= pincount:0 [ 5241.100319] flags: 0x17fffe0000040068(uptodate|lru|head|swapbacked|node= =3D0|zone=3D2|lastcpupid=3D0x3ffff) [ 5241.100323] raw: 17fffe0000040068 fffffdffd6687948 fffffdffd69ae008 0000= 000000000000 [ 5241.100325] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000= 000000000000 [ 5241.100326] head: 17fffe0000040068 fffffdffd6687948 fffffdffd69ae008 000= 0000000000000 [ 5241.100327] head: 0000000000000000 0000000000000000 00000000ffffffff 000= 0000000000000 [ 5241.100328] head: 17fffe0000000204 fffffdffd6665801 ffffffffffffffff 000= 0000000000000 [ 5241.100329] head: 0000000a00000010 0000000000000000 00000000ffffffff 000= 0000000000000 [ 5241.100330] page dumped because: VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cg= roup_disabled()) [ 5241.100338] ------------[ cut here ]------------ [ 5241.100339] WARNING: CPU: 19 PID: 78402 at include/linux/memcontrol.h:77= 5 folio_lruvec_lock_irqsave+0x140/0x150 [...] [ 5241.100374] pc : folio_lruvec_lock_irqsave+0x140/0x150 [ 5241.100375] lr : folio_lruvec_lock_irqsave+0x138/0x150 [ 5241.100376] sp : ffff80008b38b930 [...] [ 5241.100398] Call trace: [ 5241.100399] folio_lruvec_lock_irqsave+0x140/0x150 [ 5241.100401] __page_cache_release+0x90/0x300 [ 5241.100404] __folio_put+0x50/0x108 [ 5241.100406] shmem_replace_folio+0x1b4/0x240 [ 5241.100409] shmem_swapin_folio+0x314/0x528 [ 5241.100411] shmem_get_folio_gfp+0x3b4/0x930 [ 5241.100412] shmem_fault+0x74/0x160 [ 5241.100414] __do_fault+0x40/0x218 [ 5241.100417] do_shared_fault+0x34/0x1b0 [ 5241.100419] do_fault+0x40/0x168 [ 5241.100420] handle_pte_fault+0x80/0x228 [ 5241.100422] __handle_mm_fault+0x1c4/0x440 [ 5241.100424] handle_mm_fault+0x60/0x1f0 [ 5241.100426] do_page_fault+0x120/0x488 [ 5241.100429] do_translation_fault+0x4c/0x68 [ 5241.100431] do_mem_abort+0x48/0xa0 [ 5241.100434] el0_da+0x38/0xc0 [ 5241.100436] el0t_64_sync_handler+0x68/0xc0 [ 5241.100437] el0t_64_sync+0x14c/0x150 [ 5241.100439] ---[ end trace 0000000000000000 ]--- Fixes: 85ce2c517ade ("memcontrol: only transfer the memcg data for migratio= n") Signed-off-by: Baolin Wang Reviewed-by: Shakeel Butt --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index 99bd3c34f0fb..4acaf02bfe44 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1908,7 +1908,7 @@ static int shmem_replace_folio(struct folio **foliop,= gfp_t gfp, xa_lock_irq(&swap_mapping->i_pages); error =3D shmem_replace_entry(swap_mapping, swap_index, old, new); if (!error) { - mem_cgroup_migrate(old, new); + mem_cgroup_replace_folio(old, new); __lruvec_stat_mod_folio(new, NR_FILE_PAGES, 1); __lruvec_stat_mod_folio(new, NR_SHMEM, 1); __lruvec_stat_mod_folio(old, NR_FILE_PAGES, -1); --=20 2.39.3