ALSA: usb-audio: Fix races at disconnection
Close some races at disconnection of a USB audio device by adding the
chip->shutdown_mutex and chip->shutdown check at appropriate places.
The spots to put bandaids are:
- PCM prepare, hw_params and hw_free
- where the usb device is accessed for communication or get speed, in
mixer.c and others; the device speed is now cached in subs->speed
instead of accessing to chip->dev
The accesses in PCM open and close don't need the mutex protection
because these are already handled in the core PCM disconnection code.
The autosuspend/autoresume codes are still uncovered by this patch
because of possible mutex deadlocks. They'll be covered by the
upcoming change to rwsem.
Also the mixer codes are untouched, too. These will be fixed in
another patch, too.
Reported-by: Matthieu CASTET <matthieu.castet@parrot.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 55e19e1..55e741c 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -71,6 +71,8 @@
unsigned int hwptr_done;
subs = (struct snd_usb_substream *)substream->runtime->private_data;
+ if (subs->stream->chip->shutdown)
+ return SNDRV_PCM_POS_XRUN;
spin_lock(&subs->lock);
hwptr_done = subs->hwptr_done;
substream->runtime->delay = snd_usb_pcm_delay(subs,
@@ -444,7 +446,6 @@
{
int ret;
- mutex_lock(&subs->stream->chip->shutdown_mutex);
/* format changed */
stop_endpoints(subs, 0, 0, 0);
ret = snd_usb_endpoint_set_params(subs->data_endpoint,
@@ -455,7 +456,7 @@
subs->cur_audiofmt,
subs->sync_endpoint);
if (ret < 0)
- goto unlock;
+ return ret;
if (subs->sync_endpoint)
ret = snd_usb_endpoint_set_params(subs->data_endpoint,
@@ -465,9 +466,6 @@
subs->cur_rate,
subs->cur_audiofmt,
NULL);
-
-unlock:
- mutex_unlock(&subs->stream->chip->shutdown_mutex);
return ret;
}
@@ -505,7 +503,13 @@
return -EINVAL;
}
- if ((ret = set_format(subs, fmt)) < 0)
+ mutex_lock(&subs->stream->chip->shutdown_mutex);
+ if (subs->stream->chip->shutdown)
+ ret = -ENODEV;
+ else
+ ret = set_format(subs, fmt);
+ mutex_unlock(&subs->stream->chip->shutdown_mutex);
+ if (ret < 0)
return ret;
subs->interface = fmt->iface;
@@ -528,8 +532,10 @@
subs->cur_rate = 0;
subs->period_bytes = 0;
mutex_lock(&subs->stream->chip->shutdown_mutex);
- stop_endpoints(subs, 0, 1, 1);
- deactivate_endpoints(subs);
+ if (!subs->stream->chip->shutdown) {
+ stop_endpoints(subs, 0, 1, 1);
+ deactivate_endpoints(subs);
+ }
mutex_unlock(&subs->stream->chip->shutdown_mutex);
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
@@ -552,12 +558,19 @@
return -ENXIO;
}
- if (snd_BUG_ON(!subs->data_endpoint))
- return -EIO;
+ mutex_lock(&subs->stream->chip->shutdown_mutex);
+ if (subs->stream->chip->shutdown) {
+ ret = -ENODEV;
+ goto unlock;
+ }
+ if (snd_BUG_ON(!subs->data_endpoint)) {
+ ret = -EIO;
+ goto unlock;
+ }
ret = set_format(subs, subs->cur_audiofmt);
if (ret < 0)
- return ret;
+ goto unlock;
iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
@@ -567,12 +580,12 @@
subs->cur_audiofmt,
subs->cur_rate);
if (ret < 0)
- return ret;
+ goto unlock;
if (subs->need_setup_ep) {
ret = configure_endpoint(subs);
if (ret < 0)
- return ret;
+ goto unlock;
subs->need_setup_ep = false;
}
@@ -592,9 +605,11 @@
/* for playback, submit the URBs now; otherwise, the first hwptr_done
* updates for all URBs would happen at the same time when starting */
if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
- return start_endpoints(subs, 1);
+ ret = start_endpoints(subs, 1);
- return 0;
+ unlock:
+ mutex_unlock(&subs->stream->chip->shutdown_mutex);
+ return ret;
}
static struct snd_pcm_hardware snd_usb_hardware =
@@ -647,7 +662,7 @@
return 0;
}
/* check whether the period time is >= the data packet interval */
- if (snd_usb_get_speed(subs->dev) != USB_SPEED_FULL) {
+ if (subs->speed != USB_SPEED_FULL) {
ptime = 125 * (1 << fp->datainterval);
if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
hwc_debug(" > check: ptime %u > max %u\n", ptime, pt->max);
@@ -925,7 +940,7 @@
return err;
param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
- if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
+ if (subs->speed == USB_SPEED_FULL)
/* full speed devices have fixed data packet interval */
ptmin = 1000;
if (ptmin == 1000)