Commit f439696c authored Apr 17, 2019 by Ian Abbott Committed by Greg Kroah-Hartman Apr 19, 2019

staging: comedi: don't release mutex too early in comedi_auto_config()



`comedi_auto_config()` uses `dev->class_dev` for logging a kernel
message after releasing `dev->mutex`.  There is an unlikely possibility
that the Comedi device `dev` will have been removed by the
`COMEDI_DEVCONFIG` ioctl() command.  Keep hold of the mutex until the
kernel message has been sent to prevent that.  The function can call
`comedi_release_hardware_device()` on error.  In that case, the mutex
must be unlocked before that.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 2e299cc9

drivers/staging/comedi/drivers.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1059,12 +1059,12 @@ int comedi_auto_config(struct device *hardware_device,
		ret = driver->auto_attach(dev, context);
		if (ret >= 0)
		ret = comedi_device_postconfig(dev);
		mutex_unlock(&dev->mutex);

		if (ret < 0) {
		dev_warn(hardware_device,
		"driver '%s' failed to auto-configure device.\n",
		driver->driver_name);
		mutex_unlock(&dev->mutex);
		comedi_release_hardware_device(hardware_device);
		} else {
		/*
		@@ -1074,6 +1074,7 @@ int comedi_auto_config(struct device *hardware_device,
		dev_info(dev->class_dev,
		"driver '%s' has successfully auto-configured '%s'.\n",
		driver->driver_name, dev->board_name);
		mutex_unlock(&dev->mutex);
		}
		return ret;
		}