e0feaf14b1
When usb_log_enable() is called, the global apb1_log_task is used to hold the result of kthread_run(). It is possible for kthread_run() to return an error pointer, so tests of apb_log_task against NULL are insufficient to determine its validity. Note that kthread_run() never returns NULL so we don't have to check for that. But apb1_log_task is initially NULL, so that global must be both non-null and not an error in order to be considered valid. Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>