From ab605544f62b5151c2cb276f6771a8c423378926 Mon Sep 17 00:00:00 2001 From: Pingfan Liu Date: Thu, 19 Jul 2018 13:14:58 +0800 Subject: [PATCH] drivers/base: stop new probing during shutdown [ Upstream commit 3297c8fc65af5d40501ea7cddff1b195cae57e4e ] There is a race window in device_shutdown(), which may cause -1. parent device shut down before child or -2. no shutdown on a new probing device. For 1st, taking the following scenario: device_shutdown new plugin device list_del_init(parent_dev); spin_unlock(list_lock); device_add(child) probe child shutdown parent_dev --> now child is on the tail of devices_kset For 2nd, taking the following scenario: device_shutdown new plugin device device_add(dev) device_lock(dev); ... device_unlock(dev); probe dev --> now, the new occurred dev has no opportunity to shutdown To fix this race issue, just prevent the new probing request. With this logic, device_shutdown() is more similar to dpm_prepare(). Signed-off-by: Pingfan Liu Reviewed-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index b054cb2..eb066cc 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2783,6 +2783,9 @@ void device_shutdown(void) { struct device *dev, *parent; + wait_for_device_probe(); + device_block_probing(); + spin_lock(&devices_kset->list_lock); /* * Walk the devices list backward, shutting down each in turn. -- 2.7.4