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| author | Alexander Usyskin <alexander.usyskin@intel.com> | 2016-07-26 01:06:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-22 12:06:47 +0200 |
| commit | 97a19db65f50137bfffa38543add724f5222c6ae (patch) | |
| tree | 09edfafb006084bd1687c464e22b968585445c9b | |
| parent | 21fe8c7da71620f52fefef1cac94cc2180502d75 (diff) | |
| download | linux-stable-97a19db65f50137bfffa38543add724f5222c6ae.tar.gz linux-stable-97a19db65f50137bfffa38543add724f5222c6ae.tar.bz2 linux-stable-97a19db65f50137bfffa38543add724f5222c6ae.zip | |
mei: amthif: fix deadlock in initialization during a reset
commit e728ae271f4cf71218ec06a6daf61b79466cb466 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 025fb792bac3 ("mei: split amthif client init from end of clients enumeration")
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/misc/mei/amthif.c | 12 | ||||
| -rw-r--r-- | drivers/misc/mei/bus.c | 2 |
2 files changed, 9 insertions, 5 deletions
diff --git a/drivers/misc/mei/amthif.c b/drivers/misc/mei/amthif.c index a039a5df6f21..fd9271bc1a11 100644 --- a/drivers/misc/mei/amthif.c +++ b/drivers/misc/mei/amthif.c @@ -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; } diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c index 1f33fea9299f..e094df3cf2d5 100644 --- a/drivers/misc/mei/bus.c +++ b/drivers/misc/mei/bus.c @@ -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); } |