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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-02 13:47:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-02 13:47:49 -0700
commitc89ff23960f3e0b72f593a48c808c25f9e7f5a93 (patch)
tree42d3a1ce13f59eec365a1a0b1a596ef50c78641c
parent529acf58981440eefeaf1451387e2a0aa4825c12 (diff)
parent84f904ecd3aa2ccb5779b815b69c1cb592f07bb5 (diff)
Merge tag 'tty-3.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull a TTY fix from Greg Kroah-Hartman: "This is a deadlock bugfix that was easy to hit, and that the vt layer lock rework got wrong, so it reverts the logic back to the way it was in 3.3 and earlier kernels to prevent problems." * tag 'tty-3.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: vt: Fix deadlock on scroll-lock
-rw-r--r--drivers/tty/vt/keyboard.c26
1 files changed, 19 insertions, 7 deletions
diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index 86dd1e302bb..29ca20dbd33 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -1085,15 +1085,21 @@ void vt_set_led_state(int console, int leds)
*
* Handle console start. 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_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(&kbd_event_lock, flags); */
clr_vc_kbd_led(kbd, VC_SCROLLOCK);
set_leds();
- spin_unlock_irqrestore(&kbd_event_lock, flags);
+/* spin_unlock_irqrestore(&kbd_event_lock, flags); */
}
/**
@@ -1102,22 +1108,28 @@ void vt_kbd_con_start(int console)
*
* 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(&kbd_event_lock, flags); */
set_vc_kbd_led(kbd, VC_SCROLLOCK);
set_leds();
- spin_unlock_irqrestore(&kbd_event_lock, flags);
+/* spin_unlock_irqrestore(&kbd_event_lock, flags); */
}
/*
* This is the tasklet that updates LED state on all keyboards
* attached to the box. The reason we use tasklet is that we
* need to handle the scenario when keyboard handler is not
- * registered yet but we already getting updates form VT to
+ * registered yet but we already getting updates from the VT to
* update led state.
*/
static void kbd_bh(unsigned long dummy)