Commit 3ec2e370 authored by Alexander Usyskin's avatar Alexander Usyskin Committed by Greg Kroah-Hartman

mei: amthif: fix deadlock in initialization during a reset

commit e728ae27 upstream.

The device lock was unnecessary obtained in bus rescan work before the
amthif client search.  That causes incorrect lock ordering and task
hang:
...
[88004.613213] INFO: task kworker/1:14:21832 blocked for more than 120 seconds.
...
[88004.645934] Workqueue: events mei_cl_bus_rescan_work
...

The correct lock order is
 cl_bus_lock
  device_lock
   me_clients_rwsem

Move device_lock into amthif init function that called
after me_clients_rwsem is released.

This fixes regression introduced by commit:
commit 025fb792 ("mei: split amthif client init from end of clients enumeration")
Signed-off-by: default avatarAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: default avatarTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f22a8a5c
......@@ -67,8 +67,12 @@ int mei_amthif_host_init(struct mei_device *dev, struct mei_me_client *me_cl)
struct mei_cl *cl = &dev->iamthif_cl;
int ret;
if (mei_cl_is_connected(cl))
return 0;
mutex_lock(&dev->device_lock);
if (mei_cl_is_connected(cl)) {
ret = 0;
goto out;
}
dev->iamthif_state = MEI_IAMTHIF_IDLE;
......@@ -77,11 +81,13 @@ int mei_amthif_host_init(struct mei_device *dev, struct mei_me_client *me_cl)
ret = mei_cl_link(cl);
if (ret < 0) {
dev_err(dev->dev, "amthif: failed cl_link %d\n", ret);
return ret;
goto out;
}
ret = mei_cl_connect(cl, me_cl, NULL);
out:
mutex_unlock(&dev->device_lock);
return ret;
}
......
......@@ -983,12 +983,10 @@ void mei_cl_bus_rescan_work(struct work_struct *work)
container_of(work, struct mei_device, bus_rescan_work);
struct mei_me_client *me_cl;
mutex_lock(&bus->device_lock);
me_cl = mei_me_cl_by_uuid(bus, &mei_amthif_guid);
if (me_cl)
mei_amthif_host_init(bus, me_cl);
mei_me_cl_put(me_cl);
mutex_unlock(&bus->device_lock);
mei_cl_bus_rescan(bus);
}
......
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