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ALSA: x86: Fix racy access to chmap 

The access to chmap can be racy against the hotplug process, where it
recreates the chmap on the fly.  For protecting against it, a mutex is
introduced in this patch.  It's also used for protecting the change /
reference of eld and state fields, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2017-02-01 17:24:02 +01:00
parent bcce775ca8
commit 8f8d1d7fe0
2 changed files with 24 additions and 9 deletions
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32
sound/x86/intel_hdmi_audio.c
View File

@ -555,11 +555,17 @@ static int had_chmap_ctl_get(struct snd_kcontrol *kcontrol,
if (intelhaddata->drv_status == HAD_DRV_DISCONNECTED)
return -ENODEV;
if (!intelhaddata->chmap->chmap)
mutex_lock(&intelhaddata->mutex);
if (!intelhaddata->chmap->chmap) {
mutex_unlock(&intelhaddata->mutex);
return -ENODATA;
}
chmap = intelhaddata->chmap->chmap;
for (i = 0; i < chmap->channels; i++)
ucontrol->value.integer.value[i] = chmap->map[i];
mutex_unlock(&intelhaddata->mutex);
return 0;
}
@ -1352,6 +1358,7 @@ static int snd_intelhad_pcm_mmap(struct snd_pcm_substream *substream,
vma->vm_end - vma->vm_start, vma->vm_page_prot);
}
/* process mode change of the running stream; called in mutex */
static int hdmi_audio_mode_change(struct snd_intelhad *intelhaddata)
{
struct snd_pcm_substream *substream;
@ -1642,7 +1649,7 @@ static int had_process_buffer_underrun(struct snd_intelhad *intelhaddata)
return 0;
}
/* process hot plug, called from wq */
/* process hot plug, called from wq with mutex locked */
static int had_process_hot_plug(struct snd_intelhad *intelhaddata)
{
enum intel_had_aud_buf_type buf_id;
@ -1682,7 +1689,7 @@ static int had_process_hot_plug(struct snd_intelhad *intelhaddata)
return 0;
}
/* process hot unplug, called from wq */
/* process hot unplug, called from wq with mutex locked */
static int had_process_hot_unplug(struct snd_intelhad *intelhaddata)
{
enum intel_had_aud_buf_type buf_id;
@ -1751,12 +1758,14 @@ static int had_iec958_get(struct snd_kcontrol *kcontrol,
{
struct snd_intelhad *intelhaddata = snd_kcontrol_chip(kcontrol);
mutex_lock(&intelhaddata->mutex);
ucontrol->value.iec958.status[0] = (intelhaddata->aes_bits >> 0) & 0xff;
ucontrol->value.iec958.status[1] = (intelhaddata->aes_bits >> 8) & 0xff;
ucontrol->value.iec958.status[2] =
(intelhaddata->aes_bits >> 16) & 0xff;
ucontrol->value.iec958.status[3] =
(intelhaddata->aes_bits >> 24) & 0xff;
mutex_unlock(&intelhaddata->mutex);
return 0;
}
@ -1775,16 +1784,19 @@ static int had_iec958_put(struct snd_kcontrol *kcontrol,
{
unsigned int val;
struct snd_intelhad *intelhaddata = snd_kcontrol_chip(kcontrol);
int changed = 0;
val = (ucontrol->value.iec958.status[0] << 0) |
(ucontrol->value.iec958.status[1] << 8) |
(ucontrol->value.iec958.status[2] << 16) |
(ucontrol->value.iec958.status[3] << 24);
mutex_lock(&intelhaddata->mutex);
if (intelhaddata->aes_bits != val) {
intelhaddata->aes_bits = val;
return 1;
changed = 1;
}
return 1;
mutex_unlock(&intelhaddata->mutex);
return changed;
}
static struct snd_kcontrol_new had_control_iec958_mask = {
@ -1837,6 +1849,7 @@ static void had_audio_wq(struct work_struct *work)
container_of(work, struct snd_intelhad, hdmi_audio_wq);
struct intel_hdmi_lpe_audio_pdata *pdata = ctx->dev->platform_data;
mutex_lock(&ctx->mutex);
if (!pdata->hdmi_connected) {
dev_dbg(ctx->dev, "%s: Event: HAD_NOTIFY_HOT_UNPLUG\n",
__func__);
@ -1844,12 +1857,11 @@ static void had_audio_wq(struct work_struct *work)
if (ctx->state != hdmi_connector_status_connected) {
dev_dbg(ctx->dev, "%s: Already Unplugged!\n",
__func__);
return;
} else {
ctx->state = hdmi_connector_status_disconnected;
had_process_hot_unplug(ctx);
}
ctx->state = hdmi_connector_status_disconnected;
had_process_hot_unplug(ctx);
} else {
struct intel_hdmi_lpe_audio_eld *eld = &pdata->eld;
@ -1888,6 +1900,7 @@ static void had_audio_wq(struct work_struct *work)
hdmi_audio_mode_change(ctx);
}
}
mutex_unlock(&ctx->mutex);
}
/* release resources */
@ -1948,6 +1961,7 @@ static int hdmi_lpe_audio_probe(struct platform_device *pdev)
ctx = card->private_data;
spin_lock_init(&ctx->had_spinlock);
mutex_init(&ctx->mutex);
ctx->drv_status = HAD_DRV_DISCONNECTED;
ctx->dev = &pdev->dev;
ctx->card = card;

1
sound/x86/intel_hdmi_audio.h
View File

@ -139,6 +139,7 @@ struct snd_intelhad {
void __iomem *mmio_start;
unsigned int had_config_offset;
struct work_struct hdmi_audio_wq;
struct mutex mutex; /* for protecting chmap, state and eld */
};
#endif /* _INTEL_HDMI_AUDIO_ */