This is a note to let you know that I've just added the patch titled
ALSA: hda - Fix endless loop of codec configure
to the 4.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-hda-fix-endless-loop-of-codec-configure.patch
and it can be found in the queue-4.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d94815f917da770d42c377786dc428f542e38f71 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@xxxxxxx>
Date: Wed, 28 Jun 2017 12:02:02 +0200
Subject: ALSA: hda - Fix endless loop of codec configure
From: Takashi Iwai <tiwai@xxxxxxx>
commit d94815f917da770d42c377786dc428f542e38f71 upstream.
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@xxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/pci/hda/hda_codec.h | 2 ++
sound/pci/hda/hda_controller.c | 8 ++++++--
2 files changed, 8 insertions(+), 2 deletions(-)
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -294,6 +294,8 @@ 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)
--- 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;
Patches currently in stable-queue which might be from tiwai@xxxxxxx are
queue-4.11/alsa-hda-fix-endless-loop-of-codec-configure.patch
queue-4.11/alsa-hda-set-input_path-bitmap-to-zero-after-moving-it-to-new-place.patch