mei: amthif: fix deadlock in initialization during a reset (e728ae27) · Commits · 戴 / test

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 ("mei: split amthif client init from end of clients enumeration") Cc: <stable@vger.kernel.org> # 4.6+ 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>

drivers/misc/mei/amthif.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -66,8 +66,12 @@ 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;

		@@ -76,11 +80,13 @@ 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;
		}

drivers/misc/mei/bus.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -984,12 +984,10 @@ 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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