ab605544f6
[ 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 <kernelfans@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.