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/card.h b/sound/usb/card.h
index afa4f9e9b27a2673b1fc955d680859cb7f964f02..814cb357ff88235dd87f37425985602867e3f5d5 100644 (file)
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -126,6 +126,7 @@ struct snd_usb_substream {
        struct snd_usb_endpoint *sync_endpoint;
        unsigned long flags;
        bool need_setup_ep;             /* (re)configure EP at prepare? */
+       unsigned int speed;             /* USB_SPEED_XXX */
 
        u64 formats;                    /* format bitmasks (all or'ed) */
        unsigned int num_formats;               /* number of supported audio formats (list) */

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index fe56c9da38e9e6c78cdd6706f09e9639d8a502ab..c2ef11ccd66a4ff16710a6e4239ca6c3b55f5d9e 100644 (file)
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -287,25 +287,32 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request, int v
        unsigned char buf[2];
        int val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
        int timeout = 10;
-       int err;
+       int idx = 0, err;
 
        err = snd_usb_autoresume(cval->mixer->chip);
        if (err < 0)
                return -EIO;
+       mutex_lock(&chip->shutdown_mutex);
        while (timeout-- > 0) {
+               if (chip->shutdown)
+                       break;
+               idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
                if (snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), request,
                                    USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
-                                   validx, snd_usb_ctrl_intf(chip) | (cval->id << 8),
-                                   buf, val_len) >= val_len) {
+                                   validx, idx, buf, val_len) >= val_len) {
                        *value_ret = convert_signed_value(cval, snd_usb_combine_bytes(buf, val_len));
-                       snd_usb_autosuspend(cval->mixer->chip);
-                       return 0;
+                       err = 0;
+                       goto out;
                }
        }
-       snd_usb_autosuspend(cval->mixer->chip);
        snd_printdd(KERN_ERR "cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
-                   request, validx, snd_usb_ctrl_intf(chip) | (cval->id << 8), cval->val_type);
-       return -EINVAL;
+                   request, validx, idx, cval->val_type);
+       err = -EINVAL;
+
+ out:
+       mutex_unlock(&chip->shutdown_mutex);
+       snd_usb_autosuspend(cval->mixer->chip);
+       return err;
 }
 
 static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int validx, int *value_ret)
@@ -313,7 +320,7 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
        struct snd_usb_audio *chip = cval->mixer->chip;
        unsigned char buf[2 + 3*sizeof(__u16)]; /* enough space for one range */
        unsigned char *val;
-       int ret, size;
+       int idx = 0, ret, size;
        __u8 bRequest;
 
        if (request == UAC_GET_CUR) {
@@ -330,16 +337,22 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
        if (ret)
                goto error;
 
-       ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), bRequest,
+       mutex_lock(&chip->shutdown_mutex);
+       if (chip->shutdown)
+               ret = -ENODEV;
+       else {
+               idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
+               ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), bRequest,
                              USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
-                             validx, snd_usb_ctrl_intf(chip) | (cval->id << 8),
-                             buf, size);
+                             validx, idx, buf, size);
+       }
+       mutex_unlock(&chip->shutdown_mutex);
        snd_usb_autosuspend(chip);
 
        if (ret < 0) {
 error:
                snd_printk(KERN_ERR "cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
-                          request, validx, snd_usb_ctrl_intf(chip) | (cval->id << 8), cval->val_type);
+                          request, validx, idx, cval->val_type);
                return ret;
        }
 
@@ -417,7 +430,7 @@ int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
 {
        struct snd_usb_audio *chip = cval->mixer->chip;
        unsigned char buf[2];
-       int val_len, err, timeout = 10;
+       int idx = 0, val_len, err, timeout = 10;
 
        if (cval->mixer->protocol == UAC_VERSION_1) {
                val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
@@ -440,19 +453,27 @@ int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
        err = snd_usb_autoresume(chip);
        if (err < 0)
                return -EIO;
-       while (timeout-- > 0)
+       mutex_lock(&chip->shutdown_mutex);
+       while (timeout-- > 0) {
+               if (chip->shutdown)
+                       break;
+               idx = snd_usb_ctrl_intf(chip) | (cval->id << 8);
                if (snd_usb_ctl_msg(chip->dev,
                                    usb_sndctrlpipe(chip->dev, 0), request,
                                    USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
-                                   validx, snd_usb_ctrl_intf(chip) | (cval->id << 8),
-                                   buf, val_len) >= 0) {
-                       snd_usb_autosuspend(chip);
-                       return 0;
+                                   validx, idx, buf, val_len) >= 0) {
+                       err = 0;
+                       goto out;
                }
-       snd_usb_autosuspend(chip);
+       }
        snd_printdd(KERN_ERR "cannot set ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d, data = %#x/%#x\n",
-                   request, validx, snd_usb_ctrl_intf(chip) | (cval->id << 8), cval->val_type, buf[0], buf[1]);
-       return -EINVAL;
+                   request, validx, idx, cval->val_type, buf[0], buf[1]);
+       err = -EINVAL;
+
+ out:
+       mutex_unlock(&chip->shutdown_mutex);
+       snd_usb_autosuspend(chip);
+       return err;
 }
 
 static int set_cur_ctl_value(struct usb_mixer_elem_info *cval, int validx, int value)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 55e19e1b80ec4eeb282c91cea482ef7434cf8dce..55e741c5f2314bcc0e7242ddecf70c425f6fbde7 100644 (file)
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -71,6 +71,8 @@ static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream
        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 @@ static int configure_endpoint(struct snd_usb_substream *subs)
 {
        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 @@ static int configure_endpoint(struct snd_usb_substream *subs)
                                          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 @@ static int configure_endpoint(struct snd_usb_substream *subs)
                                                  subs->cur_rate,
                                                  subs->cur_audiofmt,
                                                  NULL);
-
-unlock:
-       mutex_unlock(&subs->stream->chip->shutdown_mutex);
        return ret;
 }
 
@@ -505,7 +503,13 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
                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 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
        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 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
                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 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
                                       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 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
        /* 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 @@ static int hw_check_valid_format(struct snd_usb_substream *subs,
                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 @@ static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substre
                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)

diff --git a/sound/usb/proc.c b/sound/usb/proc.c
index ebc1a5b5b3f1ba79c4c25ea66aadd34fd053e6d6..d218f763501fcdb9c4d038826a4bb12b14e4197b 100644 (file)
--- a/sound/usb/proc.c
+++ b/sound/usb/proc.c
@@ -108,7 +108,7 @@ static void proc_dump_substream_formats(struct snd_usb_substream *subs, struct s
                        }
                        snd_iprintf(buffer, "\n");
                }
-               if (snd_usb_get_speed(subs->dev) != USB_SPEED_FULL)
+               if (subs->speed != USB_SPEED_FULL)
                        snd_iprintf(buffer, "    Data packet interval: %d us\n",
                                    125 * (1 << fp->datainterval));
                // snd_iprintf(buffer, "    Max Packet Size = %d\n", fp->maxpacksize);
@@ -124,7 +124,7 @@ static void proc_dump_ep_status(struct snd_usb_substream *subs,
                return;
        snd_iprintf(buffer, "    Packet Size = %d\n", ep->curpacksize);
        snd_iprintf(buffer, "    Momentary freq = %u Hz (%#x.%04x)\n",
-                   snd_usb_get_speed(subs->dev) == USB_SPEED_FULL
+                   subs->speed == USB_SPEED_FULL
                    ? get_full_speed_hz(ep->freqm)
                    : get_high_speed_hz(ep->freqm),
                    ep->freqm >> 16, ep->freqm & 0xffff);

diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 083ed81160e58b094ee8f4fca637371aa5b5fff4..1de0c8c002a8a2d35bc80e7de9a9c764a5945fc2 100644 (file)
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -90,6 +90,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as,
        subs->direction = stream;
        subs->dev = as->chip->dev;
        subs->txfr_quirk = as->chip->txfr_quirk;
+       subs->speed = snd_usb_get_speed(subs->dev);
 
        snd_usb_set_pcm_ops(as->pcm, stream);