On Tue, Nov 14, 2017 at 08:14:34PM +0000, Ben Hutchings wrote:
On Mon, 2017-11-13 at 13:55 +0100, Greg Kroah-Hartman wrote:
4.4-stable review patch. If anyone has any objections, please let me know.
From: Alison Schofield amsfield22@gmail.com
[ Upstream commit 10e840dfb0b7fc345082dd9e5fff3c1c02e7690e ]
These stand-alone trigger drivers were using iio_trigger_put() where they should have been using iio_trigger_free(). The iio_trigger_put() adds a module_put which is bad since they never did a module_get.
In the sysfs driver, module_get/put's are used as triggers are added & removed. This extra module_put() occurs on an error path in the probe routine (probably rare).
In the bfin-timer & interrupt trigger drivers, the module resources are not explicitly managed, so it's doing a put on something that was never get'd. It occurs on the probe error path and on the remove path (not so rare).
Tested with the sysfs trigger driver. The bfin & interrupt drivers were build tested & inspected only.
In 4.4 the iio-trig-periodic-rtc seems to have the same bug (it has been removed upstream). Would it make sense to fix it in 4.4?
Probably, or if it has been removed for a good reason, we can always remove it in 4.4 :)
thanks,
greg k-h