From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52348 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757448AbcBXEEz (ORCPT ); Tue, 23 Feb 2016 23:04:55 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Hurley Subject: [PATCH 4.4 012/137] staging/speakup: Use tty_ldisc_ref() for paste kworker Date: Tue, 23 Feb 2016 19:32:23 -0800 Message-Id: <20160224033417.725762136@linuxfoundation.org> In-Reply-To: <20160224033417.270530882@linuxfoundation.org> References: <20160224033417.270530882@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Hurley commit f4f9edcf9b5289ed96113e79fa65a7bf27ecb096 upstream. 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") Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/staging/speakup/selection.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/staging/speakup/selection.c +++ b/drivers/staging/speakup/selection.c @@ -142,7 +142,9 @@ static void __speakup_paste_selection(st 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); @@ -162,6 +164,7 @@ static void __speakup_paste_selection(st tty_buffer_unlock_exclusive(&vc->port); tty_ldisc_deref(ld); +tty_unref: tty_kref_put(tty); }