From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f172.google.com (mail-ig0-f172.google.com [209.85.213.172]) by kanga.kvack.org (Postfix) with ESMTP id 3B8566B0069 for ; Thu, 9 Oct 2014 01:04:58 -0400 (EDT) Received: by mail-ig0-f172.google.com with SMTP id r2so10668797igi.11 for ; Wed, 08 Oct 2014 22:04:58 -0700 (PDT) Received: from fgwmail5.fujitsu.co.jp (fgwmail5.fujitsu.co.jp. [192.51.44.35]) by mx.google.com with ESMTPS id r8si7899630icz.31.2014.10.08.22.04.56 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 08 Oct 2014 22:04:56 -0700 (PDT) Received: from kw-mxoi2.gw.nic.fujitsu.com (unknown [10.0.237.143]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id B22803EE1B6 for ; Thu, 9 Oct 2014 14:04:54 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by kw-mxoi2.gw.nic.fujitsu.com (Postfix) with ESMTP id C044AAC026A for ; Thu, 9 Oct 2014 14:04:53 +0900 (JST) Received: from g01jpfmpwkw02.exch.g01.fujitsu.local (g01jpfmpwkw02.exch.g01.fujitsu.local [10.0.193.56]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 59A991DB8041 for ; Thu, 9 Oct 2014 14:04:53 +0900 (JST) Message-ID: <5436173A.1050002@jp.fujitsu.com> Date: Thu, 9 Oct 2014 14:03:54 +0900 From: Yasuaki Ishimatsu MIME-Version: 1.0 Subject: Re: [PATCH] driver/base/node: remove unnecessary kfree of node struct from unregister_one_node References: <542E750B.4000508@jp.fujitsu.com> <54360ABF.9030302@huawei.com> In-Reply-To: <54360ABF.9030302@huawei.com> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Xishi Qiu Cc: gregkh@linuxfoundation.org, akpm@linux-foundation.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org (2014/10/09 13:10), Xishi Qiu wrote: > On 2014/10/3 18:06, Yasuaki Ishimatsu wrote: > >> Commit 92d585ef067d ("numa: fix NULL pointer access and memory >> leak in unregister_one_node()") added kfree() of node struct in >> unregister_one_node(). But node struct is freed by node_device_release() >> which is called in unregister_node(). So by adding the kfree(), > > Hi, > > Is this path? > unregister_node() > device_unregister() > device_del() > bus_remove_device() > device_release_driver() > __device_release_driver() > devres_release_all() > release_nodes() > dr->node.release(dev, dr->data); > then which function is be called? node_device_release is called as follows: unregister_one_node() -> unregister_node() -> device_unregister() -> put_device() -> kobject_put() -> kref_put() -> kref_sub() -> kobject_release() -> kobject_cleanup() -> device_release() -> node_device_release() Thanks, Yasuaki Ishimatsu > > Thanks, > Xishi Qiu > >> node struct is freed two times. >> >> While hot removing memory, the commit leads the following BUG_ON(): >> >> kernel BUG at mm/slub.c:3346! >> invalid opcode: 0000 [#1] SMP >> [...] >> Call Trace: >> [...] unregister_one_node >> [...] try_offline_node >> [...] remove_memory >> [...] acpi_memory_device_remove >> [...] acpi_bus_trim >> [...] acpi_bus_trim >> [...] acpi_device_hotplug >> [...] acpi_hotplug_work_fn >> [...] process_one_work >> [...] worker_thread >> [...] ? rescuer_thread >> [...] kthread >> [...] ? kthread_create_on_node >> [...] ret_from_fork >> [...] ? kthread_create_on_node >> >> This patch removes unnecessary kfree() from unregister_one_node(). >> >> Signed-off-by: Yasuaki Ishimatsu >> Cc: Xishi Qiu >> Cc: Greg Kroah-Hartman >> Cc: Andrew Morton >> Cc: stable@vger.kernel.org # v3.16+ >> Fixes: 92d585ef067d "numa: fix NULL pointer access and memory leak in unregister_one_node()" >> --- >> drivers/base/node.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/drivers/base/node.c b/drivers/base/node.c >> index c6d3ae0..d51c49c 100644 >> --- a/drivers/base/node.c >> +++ b/drivers/base/node.c >> @@ -603,7 +603,6 @@ void unregister_one_node(int nid) >> return; >> >> unregister_node(node_devices[nid]); >> - kfree(node_devices[nid]); >> node_devices[nid] = NULL; >> } >> > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org