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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>
This commit is contained in:
Ian Abbott 2019-04-17 15:35:31 +01:00 committed by Greg Kroah-Hartman
parent 2e299cc969
commit f439696c81
1 changed files with 2 additions and 1 deletions
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3
drivers/staging/comedi/drivers.c
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@ -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;
}