vt: fix the keyboard/led locking
We touch the LED from both keyboard callback and direct paths. In
one case we've got the lock held way up the call chain and in the
other we haven't. This leads to complete insanity so fix it by giving
the LED bits their own lock.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index 9b4f60a..681765b 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -119,6 +119,7 @@
static struct input_handler kbd_handler;
static DEFINE_SPINLOCK(kbd_event_lock);
+static DEFINE_SPINLOCK(led_lock);
static unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; /* keyboard key bitmap */
static unsigned char shift_down[NR_SHIFT]; /* shift state counters.. */
static bool dead_key_next;
@@ -984,7 +985,7 @@
* or (ii) whatever pattern of lights people want to show using KDSETLED,
* or (iii) specified bits of specified words in kernel memory.
*/
-unsigned char getledstate(void)
+static unsigned char getledstate(void)
{
return ledstate;
}
@@ -992,7 +993,7 @@
void setledstate(struct kbd_struct *kbd, unsigned int led)
{
unsigned long flags;
- spin_lock_irqsave(&kbd_event_lock, flags);
+ spin_lock_irqsave(&led_lock, flags);
if (!(led & ~7)) {
ledioctl = led;
kbd->ledmode = LED_SHOW_IOCTL;
@@ -1000,7 +1001,7 @@
kbd->ledmode = LED_SHOW_FLAGS;
set_leds();
- spin_unlock_irqrestore(&kbd_event_lock, flags);
+ spin_unlock_irqrestore(&led_lock, flags);
}
static inline unsigned char getleds(void)
@@ -1051,8 +1052,11 @@
{
struct kbd_struct * kbd = kbd_table + console;
int ret;
+ unsigned long flags;
+ spin_lock_irqsave(&led_lock, flags);
ret = vc_kbd_led(kbd, flag);
+ spin_unlock_irqrestore(&led_lock, flags);
return ret;
}
@@ -1088,11 +1092,11 @@
void vt_kbd_con_start(int console)
{
struct kbd_struct * kbd = kbd_table + console;
-/* unsigned long flags; */
-/* spin_lock_irqsave(&kbd_event_lock, flags); */
+ unsigned long flags;
+ spin_lock_irqsave(&led_lock, flags);
clr_vc_kbd_led(kbd, VC_SCROLLOCK);
set_leds();
-/* spin_unlock_irqrestore(&kbd_event_lock, flags); */
+ spin_unlock_irqrestore(&led_lock, flags);
}
/**
@@ -1101,21 +1105,15 @@
*
* Handle console stop. This is a wrapper for the VT layer
* so that we can keep kbd knowledge internal
- *
- * FIXME: We eventually need to hold the kbd lock here to protect
- * the LED updating. We can't do it yet because fn_hold calls stop_tty
- * and start_tty under the kbd_event_lock, while normal tty paths
- * don't hold the lock. We probably need to split out an LED lock
- * but not during an -rc release!
*/
void vt_kbd_con_stop(int console)
{
struct kbd_struct * kbd = kbd_table + console;
-/* unsigned long flags; */
-/* spin_lock_irqsave(&kbd_event_lock, flags); */
+ unsigned long flags;
+ spin_lock_irqsave(&led_lock, flags);
set_vc_kbd_led(kbd, VC_SCROLLOCK);
set_leds();
-/* spin_unlock_irqrestore(&kbd_event_lock, flags); */
+ spin_unlock_irqrestore(&led_lock, flags);
}
/*
@@ -1127,7 +1125,12 @@
*/
static void kbd_bh(unsigned long dummy)
{
- unsigned char leds = getleds();
+ unsigned char leds;
+ unsigned long flags;
+
+ spin_lock_irqsave(&led_lock, flags);
+ leds = getleds();
+ spin_unlock_irqrestore(&led_lock, flags);
if (leds != ledstate) {
input_handler_for_each_handle(&kbd_handler, &leds,
@@ -2032,11 +2035,11 @@
return -EPERM;
if (arg & ~0x77)
return -EINVAL;
- spin_lock_irqsave(&kbd_event_lock, flags);
+ spin_lock_irqsave(&led_lock, flags);
kbd->ledflagstate = (arg & 7);
kbd->default_ledflagstate = ((arg >> 4) & 7);
set_leds();
- spin_unlock_irqrestore(&kbd_event_lock, flags);
+ spin_unlock_irqrestore(&led_lock, flags);
return 0;
/* the ioctls below only set the lights, not the functions */
@@ -2131,8 +2134,10 @@
clr_vc_kbd_mode(kbd, VC_CRLF);
kbd->lockstate = 0;
kbd->slockstate = 0;
+ spin_lock(&led_lock);
kbd->ledmode = LED_SHOW_FLAGS;
kbd->ledflagstate = kbd->default_ledflagstate;
+ spin_unlock(&led_lock);
/* do not do set_leds here because this causes an endless tasklet loop
when the keyboard hasn't been initialized yet */
spin_unlock_irqrestore(&kbd_event_lock, flags);