From: Peter Hurley Date: Mon, 11 Jan 2016 06:40:58 +0000 (-0800) Subject: staging/speakup: Use tty_ldisc_ref() for paste kworker X-Git-Tag: v4.1.18~70 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d515d710883d98ee77819fe9b4848bfdcfd0a324;p=thirdparty%2Fkernel%2Fstable.git staging/speakup: Use tty_ldisc_ref() for paste kworker [ Upstream commit f4f9edcf9b5289ed96113e79fa65a7bf27ecb096 ] As the function documentation for tty_ldisc_ref_wait() notes, it is only callable from a tty file_operations routine; otherwise there is no guarantee the ref won't be NULL. The key difference with the VT's paste_selection() is that is an ioctl, where __speakup_paste_selection() is completely async kworker, kicked off from interrupt context. Fixes: 28a821c30688 ("Staging: speakup: Update __speakup_paste_selection() tty (ab)usage to match vt") Cc: Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- diff --git a/drivers/staging/speakup/selection.c b/drivers/staging/speakup/selection.c index a0315701c7d96..ed68b2cfe0311 100644 --- a/drivers/staging/speakup/selection.c +++ b/drivers/staging/speakup/selection.c @@ -141,7 +141,9 @@ static void __speakup_paste_selection(struct work_struct *work) struct tty_ldisc *ld; DECLARE_WAITQUEUE(wait, current); - ld = tty_ldisc_ref_wait(tty); + ld = tty_ldisc_ref(tty); + if (!ld) + goto tty_unref; tty_buffer_lock_exclusive(&vc->port); add_wait_queue(&vc->paste_wait, &wait); @@ -161,6 +163,7 @@ static void __speakup_paste_selection(struct work_struct *work) tty_buffer_unlock_exclusive(&vc->port); tty_ldisc_deref(ld); +tty_unref: tty_kref_put(tty); }