ALSA: hda - Fix endless loop of codec configure

azx_codec_configure() loops over the codecs found on the given
controller via a linked list.  The code used to work in the past, but
in the current version, this may lead to an endless loop when a codec
binding returns an error.

The culprit is that the snd_hda_codec_configure() unregisters the
device upon error, and this eventually deletes the given codec object
from the bus.  Since the list is initialized via list_del_init(), the
next object points to the same device itself.  This behavior change
was introduced at splitting the HD-audio code code, and forgotten to
adapt it here.

For fixing this bug, just use a *_safe() version of list iteration.

Fixes: d068ebc25e6e ("ALSA: hda - Move some codes up to hdac_bus struct")
Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index d6fb2d5d01a70ef21eb533f1b86cb9c9c8f2be84..60ce1cfc300f9cb419acbc67425076c120829f13 100644 (file)
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -295,6 +295,8 @@ struct hda_codec {
 
 #define list_for_each_codec(c, bus) \
        list_for_each_entry(c, &(bus)->core.codec_list, core.list)
+#define list_for_each_codec_safe(c, n, bus)                            \
+       list_for_each_entry_safe(c, n, &(bus)->core.codec_list, core.list)
 
 /* snd_hda_codec_read/write optional flags */
 #define HDA_RW_NO_RESPONSE_FALLBACK    (1 << 0)

diff --git a/sound/pci/hda/hda_controller.c b/sound/pci/hda/hda_controller.c
index 3715a5725613bd8b8bdbcafc79b380044cacb491..1c60beb5b70a63a0ab25a828392a3cb175a4da8b 100644 (file)
--- a/sound/pci/hda/hda_controller.c
+++ b/sound/pci/hda/hda_controller.c
@@ -1337,8 +1337,12 @@ EXPORT_SYMBOL_GPL(azx_probe_codecs);
 /* configure each codec instance */
 int azx_codec_configure(struct azx *chip)
 {
-       struct hda_codec *codec;
-       list_for_each_codec(codec, &chip->bus) {
+       struct hda_codec *codec, *next;
+
+       /* use _safe version here since snd_hda_codec_configure() deregisters
+        * the device upon error and deletes itself from the bus list.
+        */
+       list_for_each_codec_safe(codec, next, &chip->bus) {
                snd_hda_codec_configure(codec);
        }
        return 0;