Thu Mar 3 05:50:31 2022 UTC ()
usbnet: Print diagnostic about refcnt stragglers.

I don't think there can be any, but this message, if printed, would
falsify my hypothesis!


(riastradh)
diff -r1.71 -r1.72 src/sys/dev/usb/usbnet.c
cvs diff -r1.71 -r1.72 src/sys/dev/usb/usbnet.c (expand / switch to unified diff)

--- src/sys/dev/usb/usbnet.c 2022/03/03 05:50:22 1.71
+++ src/sys/dev/usb/usbnet.c 2022/03/03 05:50:31 1.72
@@ -1,14 +1,14 @@ @@ -1,14 +1,14 @@
1/* $NetBSD: usbnet.c,v 1.71 2022/03/03 05:50:22 riastradh Exp $ */ 1/* $NetBSD: usbnet.c,v 1.72 2022/03/03 05:50:31 riastradh Exp $ */
2 2
3/* 3/*
4 * Copyright (c) 2019 Matthew R. Green 4 * Copyright (c) 2019 Matthew R. Green
5 * All rights reserved. 5 * All rights reserved.
6 * 6 *
7 * Redistribution and use in source and binary forms, with or without 7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions 8 * modification, are permitted provided that the following conditions
9 * are met: 9 * are met:
10 * 1. Redistributions of source code must retain the above copyright 10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer. 11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright 12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the 13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution. 14 * documentation and/or other materials provided with the distribution.
@@ -21,27 +21,27 @@ @@ -21,27 +21,27 @@
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE. 26 * SUCH DAMAGE.
27 */ 27 */
28 28
29/* 29/*
30 * Common code shared between USB network drivers. 30 * Common code shared between USB network drivers.
31 */ 31 */
32 32
33#include <sys/cdefs.h> 33#include <sys/cdefs.h>
34__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.71 2022/03/03 05:50:22 riastradh Exp $"); 34__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.72 2022/03/03 05:50:31 riastradh Exp $");
35 35
36#include <sys/param.h> 36#include <sys/param.h>
37#include <sys/kernel.h> 37#include <sys/kernel.h>
38#include <sys/kmem.h> 38#include <sys/kmem.h>
39#include <sys/module.h> 39#include <sys/module.h>
40#include <sys/atomic.h> 40#include <sys/atomic.h>
41 41
42#include <dev/usb/usbnet.h> 42#include <dev/usb/usbnet.h>
43#include <dev/usb/usbhist.h> 43#include <dev/usb/usbhist.h>
44 44
45struct usbnet_cdata { 45struct usbnet_cdata {
46 struct usbnet_chain *uncd_tx_chain; 46 struct usbnet_chain *uncd_tx_chain;
47 struct usbnet_chain *uncd_rx_chain; 47 struct usbnet_chain *uncd_rx_chain;
@@ -1661,26 +1661,30 @@ usbnet_detach(device_t self, int flags) @@ -1661,26 +1661,30 @@ usbnet_detach(device_t self, int flags)
1661 * coordination with if_mcast_op and doifioctl probably under a 1661 * coordination with if_mcast_op and doifioctl probably under a
1662 * new lock. So we'll use this kludge until that mechanism is 1662 * new lock. So we'll use this kludge until that mechanism is
1663 * invented. 1663 * invented.
1664 * 1664 *
1665 * [*] This is not exactly a documented property of the API, 1665 * [*] This is not exactly a documented property of the API,
1666 * but it is implied by the single lock in the task queue 1666 * but it is implied by the single lock in the task queue
1667 * serializing changes to the task state. 1667 * serializing changes to the task state.
1668 */ 1668 */
1669 usb_rem_task_wait(un->un_udev, &unp->unp_mcasttask, USB_TASKQ_DRIVER, 1669 usb_rem_task_wait(un->un_udev, &unp->unp_mcasttask, USB_TASKQ_DRIVER,
1670 NULL); 1670 NULL);
1671 1671
1672 mutex_enter(&unp->unp_core_lock); 1672 mutex_enter(&unp->unp_core_lock);
1673 unp->unp_refcnt--; 1673 unp->unp_refcnt--;
 1674 if (unp->unp_refcnt >= 0) {
 1675 aprint_error_dev(un->un_dev, "%d stragglers\n",
 1676 unp->unp_refcnt + 1);
 1677 }
1674 while (unp->unp_refcnt >= 0) { 1678 while (unp->unp_refcnt >= 0) {
1675 /* Wait for processes to go away */ 1679 /* Wait for processes to go away */
1676 cv_wait(&unp->unp_detachcv, &unp->unp_core_lock); 1680 cv_wait(&unp->unp_detachcv, &unp->unp_core_lock);
1677 } 1681 }
1678 mutex_exit(&unp->unp_core_lock); 1682 mutex_exit(&unp->unp_core_lock);
1679 1683
1680 usbnet_rx_list_free(un); 1684 usbnet_rx_list_free(un);
1681 usbnet_tx_list_free(un); 1685 usbnet_tx_list_free(un);
1682 1686
1683 rnd_detach_source(&unp->unp_rndsrc); 1687 rnd_detach_source(&unp->unp_rndsrc);
1684 1688
1685 cv_destroy(&unp->unp_detachcv); 1689 cv_destroy(&unp->unp_detachcv);
1686 mutex_destroy(&unp->unp_core_lock); 1690 mutex_destroy(&unp->unp_core_lock);