From: Ian Abbott Date: Wed, 11 Dec 2013 14:51:02 +0000 (+0000) Subject: staging/comedi: keep reference to class device after destroyed X-Git-Tag: v3.14-rc1~150^2~254 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8f988d8784e3fa4bb50dabeec516cd3fbdb4ea73;p=pandora-kernel.git staging/comedi: keep reference to class device after destroyed When a dynamically allocated `struct comedi_device` gets automatically unconfigured by a call to `comedi_auto_unconfig()` from a lower-level driver's bus removal function (e.g. when a USB device is disconnected), the class device in `dev->class_dev` (where `dev` points to the `struct comedi_device`) is destroyed by a call to `device_destroy()` that matches a previous call to `device_create()`. However, if the `struct comedi_device` is still associated with an open file object, the now invalid `dev->class_dev` pointer may still be passed to `dev_printk()` (via `dev_dbg()` etc.), producing bogus output or worse. To fix this, call `get_device()` on the class device if `device_create()` was successful. Add a matching call to `put_device()` in `comedi_dev_kref_release()` when the `struct comedi_device` is freed. The calls to `dev_dbg()` etc. after the call to `device_destroy()` will still produce valid output, although the device will have been unregistered in sysfs. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed