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ALSA: hda: Fix race between creating and refreshing sysfs entries

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hda_widget_sysfs_reinit() can free underlying codec->widgets structure
on which widget_tree_create() operates. Add locking to prevent such
issues from happening.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110382
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Amadeusz Sławiński 2019-05-13 11:18:01 +02:00 committed by Takashi Iwai
parent 891afcf246
commit ed180abba7
3 changed files with 11 additions and 0 deletions
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1
include/sound/hdaudio.h
View file

@ -81,6 +81,7 @@ struct hdac_device {
atomic_t in_pm; /* suspend/resume being performed */
/* sysfs */
struct mutex widget_lock;
struct hdac_widget_tree *widgets;
/* regmap */

7
sound/hda/hdac_device.c
View file

@ -55,6 +55,7 @@ int snd_hdac_device_init(struct hdac_device *codec, struct hdac_bus *bus,
codec->bus = bus;
codec->addr = addr;
codec->type = HDA_DEV_CORE;
mutex_init(&codec->widget_lock);
pm_runtime_set_active(&codec->dev);
pm_runtime_get_noresume(&codec->dev);
atomic_set(&codec->in_pm, 0);
@ -141,7 +142,9 @@ int snd_hdac_device_register(struct hdac_device *codec)
err = device_add(&codec->dev);
if (err < 0)
return err;
mutex_lock(&codec->widget_lock);
err = hda_widget_sysfs_init(codec);
mutex_unlock(&codec->widget_lock);
if (err < 0) {
device_del(&codec->dev);
return err;
@ -158,7 +161,9 @@ EXPORT_SYMBOL_GPL(snd_hdac_device_register);
void snd_hdac_device_unregister(struct hdac_device *codec)
{
if (device_is_registered(&codec->dev)) {
mutex_lock(&codec->widget_lock);
hda_widget_sysfs_exit(codec);
mutex_unlock(&codec->widget_lock);
device_del(&codec->dev);
snd_hdac_bus_remove_device(codec->bus, codec);
}
@ -404,7 +409,9 @@ int snd_hdac_refresh_widgets(struct hdac_device *codec, bool sysfs)
}
if (sysfs) {
mutex_lock(&codec->widget_lock);
err = hda_widget_sysfs_reinit(codec, start_nid, nums);
mutex_unlock(&codec->widget_lock);
if (err < 0)
return err;
}

3
sound/hda/hdac_sysfs.c
View file

@ -395,6 +395,7 @@ static int widget_tree_create(struct hdac_device *codec)
return 0;
}
/* call with codec->widget_lock held */
int hda_widget_sysfs_init(struct hdac_device *codec)
{
int err;
@ -411,11 +412,13 @@ int hda_widget_sysfs_init(struct hdac_device *codec)
return 0;
}
/* call with codec->widget_lock held */
void hda_widget_sysfs_exit(struct hdac_device *codec)
{
widget_tree_free(codec);
}
/* call with codec->widget_lock held */
int hda_widget_sysfs_reinit(struct hdac_device *codec,
hda_nid_t start_nid, int num_nodes)
{