From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 19E142C9C for ; Tue, 7 Feb 2023 13:05:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D309C433EF; Tue, 7 Feb 2023 13:05:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675775157; bh=49eVP3VvglhYDyZ+MybjCp1gHpBrluq4dXb3TC50YQg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kUnqZYsLiBItl3Yg0d57KTdUdybS+AGOLe461aSoqAWEIMRkHYTj8VcRboRoLwzz4 jizKV0FeKcqUOWTPz6q7mPejfvIyqJwFlIs3e5/7Isv+hvvcZ5QO/Rd8kLjGfFvJ+B 0KedBIzvr5nM3RAeVzSgy5rTFwc5jPPOLEmtEp90= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yu Zhao , msizanoen , Andrew Morton Subject: [PATCH 6.1 156/208] mm: multi-gen LRU: fix crash during cgroup migration Date: Tue, 7 Feb 2023 13:56:50 +0100 Message-Id: <20230207125641.519933289@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230207125634.292109991@linuxfoundation.org> References: <20230207125634.292109991@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Yu Zhao commit de08eaa6156405f2e9369f06ba5afae0e4ab3b62 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- mm/vmscan.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3290,13 +3290,16 @@ 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);