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?
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 <isimatu.yasu...@jp.fujitsu.com>
> Cc: Xishi Qiu <qiuxi...@huawei.com>
> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
> Cc: Andrew Morton <a...@linux-foundation.org>
> Cc: sta...@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;
> }
>
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