Patch "staging/speakup: Use tty_ldisc_ref() for paste kworker" has been added to the 3.10-stable tree

This is a note to let you know that I've just added the patch titled

staging/speakup: Use tty_ldisc_ref() for paste kworker

to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
staging-speakup-use-tty_ldisc_ref-for-paste-kworker.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Peter Hurley <[email protected]>
Date: Sun, 10 Jan 2016 22:40:58 -0800
Subject: staging/speakup: Use tty_ldisc_ref() for paste kworker

From: Peter Hurley <[email protected]>

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.

tty (ab)usage to match vt")

---
 drivers/staging/speakup/selection.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

@@ -139,7 +139,9 @@ 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;
 
 	/* FIXME: this is completely unsafe */
 	add_wait_queue(&vc->paste_wait, &wait);

@@ -158,6 +160,7 @@ static void __speakup_paste_selection(st
 	current->state = TASK_RUNNING;
 
 	tty_ldisc_deref(ld);
+tty_unref:
 	tty_kref_put(tty);
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-3.10/staging-speakup-use-tty_ldisc_ref-for-paste-kworker.patch queue-3.10/wan-x25-fix-use-after-free-in-x25_asy_open_tty.patch queue-3.10/pty-make-sure-super_block-is-still-valid-in-final-dev-tty-close.patch queue-3.10/pty-fix-possible-use-after-free-of-tty-driver_data.patch