mei: nfc: fix deadlock on shutdown/suspend path (4f273959) · Commits · 戴 / test

In function mei_nfc_host_exit mei_cl_remove_device cannot be called under the device mutex as device removing flow invokes the device driver remove handler that calls in turn to mei_cl_disable_device which naturally acquires the device mutex. Also remove mei_cl_bus_remove_devices which has the same issue, but is never executed as currently the only device on the mei client bus is NFC and a new device cannot be easily added till the bus revamp is completed. This fixes regression caused by commit ("mei_phy: move all nfc logic from mei driver to nfc") Prior to this change the nfc driver remove handler called to no-op disable function while actual nfc device was disabled directly from the mei driver. Reported-by:

Linus Torvalds <torvalds@linux-foundation.org> Acked-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by:

Tomas Winkler <tomas.winkler@intel.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/mei/bus.c

+0 −16

Original line number	Diff line number	Diff line
		@@ -552,22 +552,6 @@ void mei_cl_bus_rx_event(struct mei_cl *cl)
		schedule_work(&device->event_work);
		}

		void mei_cl_bus_remove_devices(struct mei_device *dev)
		{
		struct mei_cl cl, next;

		mutex_lock(&dev->device_lock);
		list_for_each_entry_safe(cl, next, &dev->device_list, device_link) {
		if (cl->device)
		mei_cl_remove_device(cl->device);

		list_del(&cl->device_link);
		mei_cl_unlink(cl);
		kfree(cl);
		}
		mutex_unlock(&dev->device_lock);
		}

		int __init mei_cl_bus_init(void)
		{
		return bus_register(&mei_cl_bus_type);

drivers/misc/mei/init.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -333,8 +333,6 @@ void mei_stop(struct mei_device *dev)

		mei_nfc_host_exit(dev);

		mei_cl_bus_remove_devices(dev);

		mutex_lock(&dev->device_lock);

		mei_wd_stop(dev);

drivers/misc/mei/nfc.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -402,11 +402,12 @@ void mei_nfc_host_exit(struct mei_device *dev)

		cldev->priv_data = NULL;

		mutex_lock(&dev->device_lock);
		/* Need to remove the device here
		* since mei_nfc_free will unlink the clients
		*/
		mei_cl_remove_device(cldev);

		mutex_lock(&dev->device_lock);
		mei_nfc_free(ndev);
		mutex_unlock(&dev->device_lock);
		}

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