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authorriastradh <riastradh@NetBSD.org>2022-04-19 09:19:53 +0000
committerriastradh <riastradh@NetBSD.org>2022-04-19 09:19:53 +0000
commita6fe4e24ed8a82d57e164cf81125322b032e8a0d (patch)
tree0d785721148e85c22c56b8d8e117316e6f1f7a5d /sys/dev/audio/audio.c
parentfed82111aa6892d74da251df870379681e3ba36a (diff)
audio(4): Wait for opens to drain in detach.
Otherwise detach may barge ahead and start freeing things before open has finished and is about to use them after free. Reported-by: syzbot+31d2619e72c2c8436cc9@syzkaller.appspotmail.com
Diffstat (limited to 'sys/dev/audio/audio.c')
-rw-r--r--sys/dev/audio/audio.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/sys/dev/audio/audio.c b/sys/dev/audio/audio.c
index 06aeec99070..625c5b63144 100644
--- a/sys/dev/audio/audio.c
+++ b/sys/dev/audio/audio.c
@@ -1,4 +1,4 @@
-/* $NetBSD: audio.c,v 1.123 2022/04/09 23:35:58 riastradh Exp $ */
+/* $NetBSD: audio.c,v 1.124 2022/04/19 09:19:53 riastradh Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -181,7 +181,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.123 2022/04/09 23:35:58 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.124 2022/04/19 09:19:53 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "audio.h"
@@ -1344,6 +1344,7 @@ audiodetach(device_t self, int flags)
{
struct audio_softc *sc;
struct audio_file *file;
+ int maj, mn;
int error;
sc = device_private(self);
@@ -1359,6 +1360,16 @@ audiodetach(device_t self, int flags)
return error;
/*
+ * Prevent new opens and wait for existing opens to complete.
+ */
+ maj = cdevsw_lookup_major(&audio_cdevsw);
+ mn = device_unit(self);
+ vdevgone(maj, mn|SOUND_DEVICE, mn|SOUND_DEVICE, VCHR);
+ vdevgone(maj, mn|AUDIO_DEVICE, mn|AUDIO_DEVICE, VCHR);
+ vdevgone(maj, mn|AUDIOCTL_DEVICE, mn|AUDIOCTL_DEVICE, VCHR);
+ vdevgone(maj, mn|MIXER_DEVICE, mn|MIXER_DEVICE, VCHR);
+
+ /*
* This waits currently running sysctls to finish if exists.
* After this, no more new sysctls will come.
*/