hmmm, new patch is the same as the old one and so will not work any
better.
On Sat, 26 Aug 2017 13:15:13 -0400,
Okash Khawaja wrote:
>
> When cursor is at beginning of an empty or whitespace-only line and
> speakup-r typed, kernel locks up. This happens because deadlock of in
> input_event function over dev->event_lock, as demonstrated by lockdep
> logs. The reason for that is speakup simulates a down arrow - because
> cursor is at an empty line - while inside key press notifier handler
> which is ultimately triggered from input_event function. The simulated
> key press leads to input_event being called again, this time under its
> own context. So the spinlock is dev->event_lock is acquired while still
> being held.
>
> This patch ensures that key press is not simulated from inside key press
> notifier handler. Instead it delegates to cursor_timer. It starts the
> timer and passes RA_DOWN_ARROW as argument. When timer handler runs and
> sees RA_DOWN_ARROW, it will then call kbd_fakekey2(RA_DOWN_ARROW) which
> will correctly simulate the keypress inside timer context.
>
> When not inside key press notifier callback, the behaviour will remain
> the same as before this patch.
>
> Signed-off-by: Okash Khawaja <okash.khawaja@xxxxxxxxx>
>
> ---
> drivers/staging/speakup/main.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> --- a/drivers/staging/speakup/main.c
> +++ b/drivers/staging/speakup/main.c
> @@ -1376,6 +1376,8 @@ static void reset_highlight_buffers(stru
>
> static int read_all_key;
>
> +static volatile int in_keyboard_notifier = 0;
> +
> static void start_read_all_timer(struct vc_data *vc, int command);
>
> enum {
> @@ -1408,7 +1410,10 @@ static void read_all_doc(struct vc_data
> cursor_track = read_all_mode;
> spk_reset_index_count(0);
> if (get_sentence_buf(vc, 0) == -1) {
> - kbd_fakekey2(vc, RA_DOWN_ARROW);
> + del_timer(&cursor_timer);
> + if (!in_keyboard_notifier)
> + speakup_fake_down_arrow();
> + start_read_all_timer(vc, RA_DOWN_ARROW);
> } else {
> say_sentence_num(0, 0);
> synth_insert_next_index(0);
> @@ -2212,8 +2217,10 @@ static int keyboard_notifier_call(struct
> int ret = NOTIFY_OK;
> static int keycode; /* to hold the current keycode */
>
> + in_keyboard_notifier = 1;
> +
> if (vc->vc_mode == KD_GRAPHICS)
> - return ret;
> + goto out;
>
> /*
> * First, determine whether we are handling a fake keypress on
> @@ -2225,7 +2232,7 @@ static int keyboard_notifier_call(struct
> */
>
> if (speakup_fake_key_pressed())
> - return ret;
> + goto out;
>
> switch (code) {
> case KBD_KEYCODE:
> @@ -2266,6 +2273,8 @@ static int keyboard_notifier_call(struct
> break;
> }
> }
> +out:
> + in_keyboard_notifier = 0;
> return ret;
> }
>
--
Your life is like a penny. You're going to lose it. The question is:
How do
you spend it?
John Covici
covici@xxxxxxxxxxxxxx
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