ALSA: hda: Fix connection list comparison in proc output
print_conn_list() compares the raw hardware connection list with the
connection list cached by the HDA driver. When they differ, it prints an
additional "In-driver Connection" line so that /proc/asound/card*/codec#*
shows the topology actually used by the driver.
The comparison currently passes conn_len directly to memcmp(). However,
conn_len is a number of connection-list entries, while memcmp() expects a
size in bytes. Both list and conn are arrays of hda_nid_t, which is u16,
so only half of the connection data is compared.
For example, for two-entry lists such as:
hardware: 0x0c 0x0d
cached: 0x0c 0x0e
conn_len is 2, and the current comparison checks only the first hda_nid_t.
The lists are therefore incorrectly treated as identical even though the
second connection differs.
This can happen legitimately when codec fixups replace a cached connection
list with snd_hda_override_conn_list(). The codec routing used by the
driver is not affected, but the proc output can hide the overridden
driver-visible routing and provide misleading topology information during
codec debugging.
Convert the entry count to a byte size so that memcmp() covers the
complete connection list.
Fixes: 8b2c7a5c404d ("ALSA: hda - Add In-driver connection info")
Signed-off-by: Xu Rao <raoxu@uniontech.com>
Link: https://patch.msgid.link/7B802A4E225CC808+20260818083808.2735120-1-raoxu@uniontech.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/hda/common/proc.c b/sound/hda/common/proc.c
index c83796b1..3dabdb4 100644
--- a/sound/hda/common/proc.c
+++ b/sound/hda/common/proc.c
@@ -624,7 +624,7 @@ static void print_conn_list(struct snd_info_buffer *buffer,
/* Get Cache connections info */
cache_len = snd_hda_get_conn_list(codec, nid, &list);
if (cache_len >= 0 && (cache_len != conn_len ||
- memcmp(list, conn, conn_len) != 0)) {
+ memcmp(list, conn, conn_len * sizeof(*conn)) != 0)) {
snd_iprintf(buffer, " In-driver Connection: %d\n", cache_len);
if (cache_len > 0) {
snd_iprintf(buffer, " ");
