[src/trunk]: src/sys/dev Ensure we still have a virtual channel after sleepin...

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

details:   https://anonhg.NetBSD.org/src/rev/261d1d35e1a2
branches:  trunk
changeset: 351665:261d1d35e1a2
user:      nat <nat%NetBSD.org@localhost>
date:      Tue Feb 21 20:23:37 2017 +0000

description:
Ensure we still have a virtual channel after sleeping on sc_lock.

Addresses PR kern/51746: Panics from audio.

diffstat:

 sys/dev/audio.c |  29 +++++++++++++++++++++--------
 1 files changed, 21 insertions(+), 8 deletions(-)

diffs (93 lines):

diff -r b357b8d3162c -r 261d1d35e1a2 sys/dev/audio.c
--- a/sys/dev/audio.c   Tue Feb 21 19:53:49 2017 +0000
+++ b/sys/dev/audio.c   Tue Feb 21 20:23:37 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.306 2017/02/14 09:41:29 nat Exp $  */
+/*     $NetBSD: audio.c,v 1.307 2017/02/21 20:23:37 nat Exp $  */
 
 /*-
  * Copyright (c) 2016 Nathanial Sloss <nathanialsloss%yahoo.com.au@localhost>
@@ -148,7 +148,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.306 2017/02/14 09:41:29 nat Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.307 2017/02/21 20:23:37 nat Exp $");
 
 #include "audio.h"
 #if NAUDIO > 0
@@ -339,7 +339,8 @@
 
 static int     audio_enter(dev_t, krw_t, struct audio_softc **);
 static void    audio_exit(struct audio_softc *);
-static int     audio_waitio(struct audio_softc *, kcondvar_t *);
+static int     audio_waitio(struct audio_softc *, kcondvar_t *,
+                            struct virtual_channel *);
 
 int audioclose(struct file *);
 int audioread(struct file *, off_t *, struct uio *, kauth_cred_t, int);
@@ -1516,8 +1517,10 @@
  * Wait for I/O to complete, releasing device lock.
  */
 static int
-audio_waitio(struct audio_softc *sc, kcondvar_t *chan)
+audio_waitio(struct audio_softc *sc, kcondvar_t *chan, struct virtual_channel *vc)
 {
+       struct audio_chan *vchan;
+       bool found = false;
        int error;
 
        KASSERT(mutex_owned(sc->sc_lock));
@@ -1526,6 +1529,16 @@
        /* Wait for pending I/O to complete. */
        error = cv_wait_sig(chan, sc->sc_lock);
 
+       found = false;
+       SIMPLEQ_FOREACH(vchan, &sc->sc_audiochan, entries) {
+               if (vchan->vc == vc) {
+                       found = true;
+                       break;
+               }
+       }
+       if (found == false)
+               error = EIO;
+
        return error;
 }
 
@@ -2325,7 +2338,7 @@
                        audio_stream_get_used(&vc->sc_mpr.s),
                        cb->drops));
                mutex_exit(sc->sc_intr_lock);
-               error = audio_waitio(sc, &sc->sc_wchan);
+               error = audio_waitio(sc, &sc->sc_wchan, vc);
                mutex_enter(sc->sc_intr_lock);
                if (sc->sc_dying)
                        error = EIO;
@@ -2476,7 +2489,7 @@
                                         vc->sc_mpr.stamp, vc->sc_wstamp));
                                if (ioflag & IO_NDELAY)
                                        return EWOULDBLOCK;
-                               error = audio_waitio(sc, &sc->sc_rchan);
+                               error = audio_waitio(sc, &sc->sc_rchan, vc);
                                if (sc->sc_dying)
                                        error = EIO;
                                if (error)
@@ -2504,7 +2517,7 @@
                        if (ioflag & IO_NDELAY)
                                return EWOULDBLOCK;
                        DPRINTFN(2, ("audio_read: sleep used=%d\n", used));
-                       error = audio_waitio(sc, &sc->sc_rchan);
+                       error = audio_waitio(sc, &sc->sc_rchan, vc);
                        if (sc->sc_dying)
                                error = EIO;
                        if (error)
@@ -2832,7 +2845,7 @@
                        mutex_exit(sc->sc_intr_lock);
                        if (ioflag & IO_NDELAY)
                                return EWOULDBLOCK;
-                       error = audio_waitio(sc, &sc->sc_wchan);
+                       error = audio_waitio(sc, &sc->sc_wchan, vc);
                        if (sc->sc_dying)
                                error = EIO;
                        if (error)