From 0defbd9aca4620a135f08b0f9073c168e8263c80 Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastradh@NetBSD.org>
Date: Sat, 25 Dec 2021 14:04:55 +0000
Subject: [PATCH] ukbd(4): Avoid races in LED setting on attach.
- Don't reuse sc_delay for LED task -- a keyboard interrupt shortly
after attach might reset sc_delay so that the LEDs never get turned
back off.
- Don't turn the LEDs back off after attach if something else has
already changed them by the time the callout fires.
(And make sure to callout_halt before done this time!)
---
sys/dev/usb/ukbd.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/sys/dev/usb/ukbd.c b/sys/dev/usb/ukbd.c
index 90db0bccf05d..45a92535c38c 100644
--- a/sys/dev/usb/ukbd.c
+++ b/sys/dev/usb/ukbd.c
@@ -270,6 +270,8 @@ struct ukbd_softc {
struct hid_location sc_compose;
int sc_leds;
struct usb_task sc_ledtask;
+ struct callout sc_ledreset;
+ int sc_leds_set;
device_t sc_wskbddev;
#if defined(WSDISPLAY_COMPAT_RAWKBD)
@@ -483,11 +485,13 @@ ukbd_attach(device_t parent, device_t self, void *aux)
sc->sc_data_r = 0;
usb_init_task(&sc->sc_ledtask, ukbd_set_leds_task, sc, 0);
+ callout_init(&sc->sc_ledreset, 0);
/* Flash the leds; no real purpose, just shows we're alive. */
ukbd_set_leds(sc, WSKBD_LED_SCROLL | WSKBD_LED_NUM | WSKBD_LED_CAPS
| WSKBD_LED_COMPOSE);
- callout_reset(&sc->sc_delay, mstohz(400), ukbd_delayed_leds_off, sc);
+ callout_reset(&sc->sc_ledreset, mstohz(400), ukbd_delayed_leds_off,
+ sc);
sc->sc_wskbddev = config_found(self, &a, wskbddevprint, CFARGS_NONE);
@@ -573,6 +577,7 @@ ukbd_detach(device_t self, int flags)
rv = config_detach(sc->sc_wskbddev, flags);
callout_halt(&sc->sc_delay, NULL);
+ callout_halt(&sc->sc_ledreset, NULL);
usb_rem_task_wait(sc->sc_hdev.sc_parent->sc_udev, &sc->sc_ledtask,
USB_TASKQ_DRIVER, NULL);
@@ -715,6 +720,13 @@ ukbd_delayed_leds_off(void *addr)
{
struct ukbd_softc *sc = addr;
+ /*
+ * If the LEDs have already been set after attach, other than
+ * by our initial flashing of them, leave them be.
+ */
+ if (sc->sc_leds_set)
+ return;
+
ukbd_set_leds(sc, 0);
}
@@ -880,6 +892,8 @@ ukbd_set_leds(void *v, int leds)
if (sc->sc_dying)
return;
+ sc->sc_leds_set = 1;
+
if (sc->sc_leds == leds)
return;