commit 7f84ff68 upstream.

The line6 toneport driver has code for some delayed initialization,
and this hits the kernel Oops because mutex and other sleepable
functions are used in the timer callback.  Fix the abuse by a delayed
work instead so that everything works gracefully.

Reported-by: syzbot+a07d0142e74fdd595cfb@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>