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author | Pingfan Liu <kernelfans@gmail.com> | 2018-07-19 13:14:58 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-26 08:36:34 +0200 |
commit | e6f55802bac406cd1894351ac8b13aa5d5459da6 (patch) | |
tree | aed9c60868e4657a268ec90a33eecebf181561b7 | |
parent | 0a10ce961bb34a0a42e60534479d8a79fc46d927 (diff) | |
download | linux-stable-e6f55802bac406cd1894351ac8b13aa5d5459da6.tar.gz linux-stable-e6f55802bac406cd1894351ac8b13aa5d5459da6.tar.bz2 linux-stable-e6f55802bac406cd1894351ac8b13aa5d5459da6.zip |
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 <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>
-rw-r--r-- | drivers/base/core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index a0ed957d738f..f43caad30e1e 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2072,6 +2072,9 @@ 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. |