ALSA: usb-audio: Avoid autopm calls after disconnection

Add a similar protection against the disconnection race and the
invalid use of usb instance after disconnection, as well as we've done
for the USB audio PCM.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=51201

Reviewd-by: Clemens Ladisch <clemens@ladisch.de>
Tested-by: Clemens Ladisch <clemens@ladisch.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 22 insertions, 1 deletions

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index eeefbce3873c..c0054ee9389b 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -116,6 +116,7 @@ struct snd_usb_midi {
         struct list_head list;
         struct timer_list error_timer;
         spinlock_t disc_lock;
+        struct rw_semaphore disc_rwsem;
         struct mutex mutex;
         u32 usb_id;
         int next_midi_device;
@@ -1038,6 +1039,12 @@ static void substream_open(struct snd_rawmidi_substream *substream, int open)
         struct snd_usb_midi* umidi = substream->rmidi->private_data;
         struct snd_kcontrol *ctl;
 
+        down_read(&umidi->disc_rwsem);
+        if (umidi->disconnected) {
+                up_read(&umidi->disc_rwsem);
+                return;
+        }
+
         mutex_lock(&umidi->mutex);
         if (open) {
                 if (umidi->opened++ == 0 && umidi->roland_load_ctl) {
@@ -1056,6 +1063,7 @@ static void substream_open(struct snd_rawmidi_substream *substream, int open)
                 }
         }
         mutex_unlock(&umidi->mutex);
+        up_read(&umidi->disc_rwsem);
 }
 
 static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
@@ -1076,8 +1084,15 @@ static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
                 snd_BUG();
                 return -ENXIO;
         }
+
+        down_read(&umidi->disc_rwsem);
+        if (umidi->disconnected) {
+                up_read(&umidi->disc_rwsem);
+                return -ENODEV;
+        }
         err = usb_autopm_get_interface(umidi->iface);
         port->autopm_reference = err >= 0;
+        up_read(&umidi->disc_rwsem);
         if (err < 0 && err != -EACCES)
                 return -EIO;
         substream->runtime->private_data = port;
@@ -1092,8 +1107,10 @@ static int snd_usbmidi_output_close(struct snd_rawmidi_substream *substream)
         struct usbmidi_out_port *port = substream->runtime->private_data;
 
         substream_open(substream, 0);
-        if (port->autopm_reference)
+        down_read(&umidi->disc_rwsem);
+        if (!umidi->disconnected && port->autopm_reference)
                 usb_autopm_put_interface(umidi->iface);
+        up_read(&umidi->disc_rwsem);
         return 0;
 }
 
@@ -1403,9 +1420,12 @@ void snd_usbmidi_disconnect(struct list_head* p)
          * a timer may submit an URB. To reliably break the cycle
          * a flag under lock must be used
          */
+        down_write(&umidi->disc_rwsem);
         spin_lock_irq(&umidi->disc_lock);
         umidi->disconnected = 1;
         spin_unlock_irq(&umidi->disc_lock);
+        up_write(&umidi->disc_rwsem);
+
         for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
                 struct snd_usb_midi_endpoint* ep = &umidi->endpoints[i];
                 if (ep->out)
@@ -2117,6 +2137,7 @@ int snd_usbmidi_create(struct snd_card *card,
         umidi->usb_protocol_ops = &snd_usbmidi_standard_ops;
         init_timer(&umidi->error_timer);
         spin_lock_init(&umidi->disc_lock);
+        init_rwsem(&umidi->disc_rwsem);
         mutex_init(&umidi->mutex);
         umidi->usb_id = USB_ID(le16_to_cpu(umidi->dev->descriptor.idVendor),
                                le16_to_cpu(umidi->dev->descriptor.idProduct));