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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CD02C38142 for ; Wed, 1 Feb 2023 00:45:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231829AbjBAApN (ORCPT ); Tue, 31 Jan 2023 19:45:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231835AbjBAApD (ORCPT ); Tue, 31 Jan 2023 19:45:03 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D0F64FC2E; Tue, 31 Jan 2023 16:45:02 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D758AB81FC6; Wed, 1 Feb 2023 00:45:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 775A0C433D2; Wed, 1 Feb 2023 00:44:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1675212299; bh=r3/kiPjbOX6tK6bXj9ZUjARQpn0TaD3qLbA4VnfBUko=; h=Date:To:From:Subject:From; b=JXoJUCyUc0678OHqDr9xJ6/wRofbVjzIOKMM5b1ar6dm/4QVUqjvQiXV4Qnl1GURU YeXyW1EVOjluRQVCRVNAisn6dW6p8bUJjasylIiCdESnNxz43FFlW2Mb522vHxPn8v tTVD8Cobv1m9v5vju3lIbiczp5wO792HmKgVztJo= Date: Tue, 31 Jan 2023 16:44:59 -0800 To: mm-commits@vger.kernel.org, stable@vger.kernel.org, msizanoen@qtmlabs.xyz, yuzhao@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-multi-gen-lru-fix-crash-during-cgroup-migration.patch removed from -mm tree Message-Id: <20230201004459.775A0C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm: multi-gen LRU: fix crash during cgroup migration has been removed from the -mm tree. Its filename was mm-multi-gen-lru-fix-crash-during-cgroup-migration.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Yu Zhao Subject: mm: multi-gen LRU: fix crash during cgroup migration Date: Sun, 15 Jan 2023 20:44:05 -0700 lru_gen_migrate_mm() assumes lru_gen_add_mm() runs prior to itself. This isn't true for the following scenario: CPU 1 CPU 2 clone() cgroup_can_fork() cgroup_procs_write() cgroup_post_fork() task_lock() lru_gen_migrate_mm() task_unlock() task_lock() lru_gen_add_mm() task_unlock() And when the above happens, kernel crashes because of linked list corruption (mm_struct->lru_gen.list). Link: https://lore.kernel.org/r/20230115134651.30028-1-msizanoen@qtmlabs.xyz/ Link: https://lkml.kernel.org/r/20230116034405.2960276-1-yuzhao@google.com Fixes: bd74fdaea146 ("mm: multi-gen LRU: support page table walks") Signed-off-by: Yu Zhao Reported-by: msizanoen Tested-by: msizanoen Cc: [6.1+] Signed-off-by: Andrew Morton --- mm/vmscan.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/vmscan.c~mm-multi-gen-lru-fix-crash-during-cgroup-migration +++ a/mm/vmscan.c @@ -3323,13 +3323,16 @@ void lru_gen_migrate_mm(struct mm_struct if (mem_cgroup_disabled()) return; + /* migration can happen before addition */ + if (!mm->lru_gen.memcg) + return; + rcu_read_lock(); memcg = mem_cgroup_from_task(task); rcu_read_unlock(); if (memcg == mm->lru_gen.memcg) return; - VM_WARN_ON_ONCE(!mm->lru_gen.memcg); VM_WARN_ON_ONCE(list_empty(&mm->lru_gen.list)); lru_gen_del_mm(mm); _ Patches currently in -mm which might be from yuzhao@google.com are