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authorOkash Khawaja <okash.khawaja@gmail.com>2017-09-05 12:51:59 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-09-18 12:25:31 +0200
commite5f5d0e20b6cecc0ebe6fc8e7df6f8823ad2d594 (patch)
tree807859644cdcbfbdd37853c8e5ec1da741dbd673 /drivers/staging/speakup
parentb72703e26b9478da531144ce5c4552dd22f1103d (diff)
staging: speakup: fix speakup-r empty line lockup
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@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/speakup')
-rw-r--r--drivers/staging/speakup/main.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/staging/speakup/main.c b/drivers/staging/speakup/main.c
index 67956e24779c..56f7be6af1f6 100644
--- a/drivers/staging/speakup/main.c
+++ b/drivers/staging/speakup/main.c
@@ -1376,6 +1376,8 @@ static void reset_highlight_buffers(struct vc_data *);
static int read_all_key;
+static int in_keyboard_notifier;
+
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 *vc)
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 notifier_block *nb,
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 notifier_block *nb,
*/
if (speakup_fake_key_pressed())
- return ret;
+ goto out;
switch (code) {
case KBD_KEYCODE:
@@ -2266,6 +2273,8 @@ static int keyboard_notifier_call(struct notifier_block *nb,
break;
}
}
+out:
+ in_keyboard_notifier = 0;
return ret;
}