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>

1 files changed, 12 insertions, 8 deletions

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index febadc9ed593..5689393f8da7 100644
--- 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);
                 }
         }