| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 03/54] staging/speakup: Use tty_ldisc_ref() for paste kworker | Date | Tue, 23 Feb 2016 19:33:20 -0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Peter Hurley <peter@hurleysoftware.com>
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 <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 @@ -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); }
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