ALSA: hda - Avoid access of amp cache element outside mutex

The access to a cache array element could be invalid outside the
mutex, so copy locally for the later references.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index febadc9..5689393 100644 (file)
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -1807,7 +1807,7 @@ update_amp_hash(struct hda_codec *codec, hda_nid_t nid, int ch,
 /*
  * write the current volume in info to the h/w
  */
-static void put_vol_mute(struct hda_codec *codec, struct hda_amp_info *info,
+static void put_vol_mute(struct hda_codec *codec, unsigned int amp_caps,
                         hda_nid_t nid, int ch, int direction, int index,
                         int val)
 {
@@ -1816,8 +1816,8 @@ static void put_vol_mute(struct hda_codec *codec, struct hda_amp_info *info,
        parm = ch ? AC_AMP_SET_RIGHT : AC_AMP_SET_LEFT;
        parm |= direction == HDA_OUTPUT ? AC_AMP_SET_OUTPUT : AC_AMP_SET_INPUT;
        parm |= index << AC_AMP_SET_INDEX_SHIFT;
-       if ((val & HDA_AMP_MUTE) && !(info->amp_caps & AC_AMPCAP_MUTE) &&
-           (info->amp_caps & AC_AMPCAP_MIN_MUTE))
+       if ((val & HDA_AMP_MUTE) && !(amp_caps & AC_AMPCAP_MUTE) &&
+           (amp_caps & AC_AMPCAP_MIN_MUTE))
                ; /* set the zero value as a fake mute */
        else
                parm |= val;
@@ -1854,6 +1854,7 @@ static int codec_amp_update(struct hda_codec *codec, hda_nid_t nid, int ch,
                            bool init_only)
 {
        struct hda_amp_info *info;
+       unsigned int caps;
        unsigned int cache_only;
 
        if (snd_BUG_ON(mask & ~0xff))
@@ -1873,9 +1874,10 @@ static int codec_amp_update(struct hda_codec *codec, hda_nid_t nid, int ch,
        }
        info->vol[ch] = val;
        cache_only = info->head.dirty = codec->cached_write;
+       caps = info->amp_caps;
        mutex_unlock(&codec->hash_mutex);
        if (!cache_only)
-               put_vol_mute(codec, info, nid, ch, direction, idx, val);
+               put_vol_mute(codec, caps, nid, ch, direction, idx, val);
        return 1;
 }
 
@@ -1967,23 +1969,25 @@ void snd_hda_codec_resume_amp(struct hda_codec *codec)
                u32 key;
                hda_nid_t nid;
                unsigned int idx, dir, ch;
+               struct hda_amp_info info;
 
                buffer = snd_array_elem(&codec->amp_cache.buf, i);
                if (!buffer->head.dirty)
                        continue;
                buffer->head.dirty = 0;
-               key = buffer->head.key;
+               info = *buffer;
+               key = info.head.key;
                if (!key)
                        continue;
                nid = key & 0xff;
                idx = (key >> 16) & 0xff;
                dir = (key >> 24) & 0xff;
                for (ch = 0; ch < 2; ch++) {
-                       if (!(buffer->head.val & INFO_AMP_VOL(ch)))
+                       if (!(info.head.val & INFO_AMP_VOL(ch)))
                                continue;
                        mutex_unlock(&codec->hash_mutex);
-                       put_vol_mute(codec, buffer, nid, ch, dir, idx,
-                                    buffer->vol[ch]);
+                       put_vol_mute(codec, info.amp_caps, nid, ch, dir, idx,
+                                    info.vol[ch]);
                        mutex_lock(&codec->hash_mutex);
                }
        }