[src/trunk]: src/sys/dev/usb Don't allow open of /dev/usb if there are no att...

[skrll <skrll%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/32f56932c045
branches:  trunk
changeset: 933559:32f56932c045
user:      skrll <skrll%NetBSD.org@localhost>
date:      Wed May 27 07:17:45 2020 +0000

description:
Don't allow open of /dev/usb if there are no attached busses.

PR kern/55303 mutex_vector_enter,512: uninitialized lock

diffstat:

 sys/dev/usb/usb.c |  15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diffs (50 lines):

diff -r 24c07045bcd5 -r 32f56932c045 sys/dev/usb/usb.c
--- a/sys/dev/usb/usb.c Wed May 27 06:43:22 2020 +0000
+++ b/sys/dev/usb/usb.c Wed May 27 07:17:45 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: usb.c,v 1.186 2020/05/26 19:55:43 skrll Exp $  */
+/*     $NetBSD: usb.c,v 1.187 2020/05/27 07:17:45 skrll Exp $  */
 
 /*
  * Copyright (c) 1998, 2002, 2008, 2012 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: usb.c,v 1.186 2020/05/26 19:55:43 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: usb.c,v 1.187 2020/05/27 07:17:45 skrll Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -232,6 +232,11 @@
 Static void    usb_event_thread(void *);
 Static void    usb_task_thread(void *);
 
+/*
+ * Count of USB busses
+ */
+int nusbbusses = 0;
+
 #define USB_MAX_EVENTS 100
 struct usb_event_q {
        struct usb_event ue;
@@ -378,6 +383,9 @@
 
        USBHIST_FUNC(); USBHIST_CALLED(usbdebug);
 
+       /* Protected by KERNEL_LOCK */
+       nusbbusses++;
+
        sc->sc_bus->ub_usbctl = self;
        sc->sc_port.up_power = USB_MAX_POWER;
 
@@ -719,6 +727,9 @@
        int unit = minor(dev);
        struct usb_softc *sc;
 
+       if (nusbbusses == 0)
+               return ENXIO;
+
        if (unit == USB_DEV_MINOR) {
                if (usb_dev_open)
                        return EBUSY;