From d94815f917da770d42c377786dc428f542e38f71 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Wed, 28 Jun 2017 12:02:02 +0200 Subject: [PATCH] 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 Cc: Signed-off-by: Takashi Iwai --- sound/pci/hda/hda_codec.h | 2 ++ sound/pci/hda/hda_controller.c | 8 ++++++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h index d6fb2d5..60ce1cf 100644 --- 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 3715a57..1c60beb 100644 --- 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; -- 2.7.4