The following reply was made to PR kern/53447; it has been noted by GNATS.
From: christos%zoulas.com@localhost (Christos Zoulas)
To: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost,
gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Cc:
Subject: Re: kern/53447: usb lock problem, mutex_enter
Date: Thu, 12 Jul 2018 17:51:34 -0400
On Jul 12, 9:25pm, phil%netbsd.org@localhost (phil%netbsd.org@localhost) wrote:
-- Subject: kern/53447: usb lock problem, mutex_enter
| >Number: 53447
| >Category: kern
| >Synopsis: usb lock problem, mutex_enter
| >Confidential: no
| >Severity: serious
| >Priority: medium
| >Responsible: kern-bug-people
| >State: open
| >Class: sw-bug
| >Submitter-Id: net
| >Arrival-Date: Thu Jul 12 21:25:00 +0000 2018
| >Originator: Phil Nelson
| >Release: NetBSD HEAD 8.99.21
| >Organization:
| >Environment:
| 8.99.21 NetBSD 8.99.21 (STEELHEAD) #8: Thu Jul 12 13:34:13 PDT 2018 amd64
| >Description:
| When asking for the root device using a USB console keyboard, typing a character to answer the root device name causes a Mutex_error, mutex_vector_enter 528: spin lock held.
Try this:
Index: xhci.c
===================================================================
RCS file: /cvsroot/src/sys/dev/usb/xhci.c,v
retrieving revision 1.93
diff -u -u -r1.93 xhci.c
--- xhci.c 29 Jun 2018 17:48:24 -0000 1.93
+++ xhci.c 12 Jul 2018 21:50:51 -0000
@@ -1206,7 +1206,7 @@
static inline bool
xhci_polling_p(struct xhci_softc * const sc)
{
- return sc->sc_bus.ub_usepolling || sc->sc_bus2.ub_usepolling;
+ return cold || sc->sc_bus.ub_usepolling || sc->sc_bus2.ub_usepolling;
}
int
@@ -3983,6 +3983,7 @@
struct xhci_ring * const tr = &xs->xs_ep[dci].xe_tr;
struct xhci_xfer * const xx = XHCI_XFER2XXFER(xfer);
const uint32_t len = xfer->ux_length;
+ const bool polling = xhci_polling_p(sc);
usb_dma_t * const dma = &xfer->ux_dmabuf;
uint64_t parameter;
uint32_t status;
@@ -4009,13 +4010,15 @@
XHCI_TRB_3_IOC_BIT;
xhci_trb_put(&xx->xx_trb[i++], parameter, status, control);
- mutex_enter(&tr->xr_lock);
+ if (!polling)
+ mutex_enter(&tr->xr_lock);
xhci_ring_put(sc, tr, xfer, xx->xx_trb, i);
- mutex_exit(&tr->xr_lock);
+ if (!polling)
+ mutex_exit(&tr->xr_lock);
xhci_db_write_4(sc, XHCI_DOORBELL(xs->xs_idx), dci);
- if (xfer->ux_timeout && !xhci_polling_p(sc)) {
+ if (xfer->ux_timeout && !polling) {
callout_reset(&xfer->ux_callout, mstohz(xfer->ux_timeout),
xhci_timeout, xfer);
}