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.slawin...@linux.intel.com>
---
 include/sound/hdaudio.h   |  1 +
 sound/hda/hdac_sysfs.c    | 22 +++++++++++++++++++---
 sound/pci/hda/hda_codec.c |  2 ++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/include/sound/hdaudio.h b/include/sound/hdaudio.h
index 45f944d57982..85835d0c33cc 100644
--- a/include/sound/hdaudio.h
+++ b/include/sound/hdaudio.h
@@ -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 */
diff --git a/sound/hda/hdac_sysfs.c b/sound/hda/hdac_sysfs.c
index fb2aa344981e..5352e5db814c 100644
--- a/sound/hda/hdac_sysfs.c
+++ b/sound/hda/hdac_sysfs.c
@@ -399,21 +399,28 @@ int hda_widget_sysfs_init(struct hdac_device *codec)
 {
        int err;
 
-       if (codec->widgets)
+       mutex_lock(&codec->widget_lock);
+       if (codec->widgets) {
+               mutex_unlock(&codec->widget_lock);
                return 0; /* already created */
+       }
 
        err = widget_tree_create(codec);
        if (err < 0) {
                widget_tree_free(codec);
+               mutex_unlock(&codec->widget_lock);
                return err;
        }
 
+       mutex_unlock(&codec->widget_lock);
        return 0;
 }
 
 void hda_widget_sysfs_exit(struct hdac_device *codec)
 {
+       mutex_lock(&codec->widget_lock);
        widget_tree_free(codec);
+       mutex_unlock(&codec->widget_lock);
 }
 
 int hda_widget_sysfs_reinit(struct hdac_device *codec,
@@ -424,16 +431,23 @@ int hda_widget_sysfs_reinit(struct hdac_device *codec,
        hda_nid_t nid;
        int i;
 
-       if (!codec->widgets)
+       mutex_lock(&codec->widget_lock);
+
+       if (!codec->widgets) {
+               mutex_unlock(&codec->widget_lock);
                return hda_widget_sysfs_init(codec);
+       }
 
        tree = kmemdup(codec->widgets, sizeof(*tree), GFP_KERNEL);
-       if (!tree)
+       if (!tree) {
+               mutex_unlock(&codec->widget_lock);
                return -ENOMEM;
+       }
 
        tree->nodes = kcalloc(num_nodes + 1, sizeof(*tree->nodes), GFP_KERNEL);
        if (!tree->nodes) {
                kfree(tree);
+               mutex_unlock(&codec->widget_lock);
                return -ENOMEM;
        }
 
@@ -460,5 +474,7 @@ int hda_widget_sysfs_reinit(struct hdac_device *codec,
        codec->widgets = tree;
 
        kobject_uevent(tree->root, KOBJ_CHANGE);
+
+       mutex_unlock(&codec->widget_lock);
        return 0;
 }
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 701a69d856f5..a5746df5c94b 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -870,6 +870,8 @@ static int snd_hda_codec_device_init(struct hda_bus *bus, 
struct snd_card *card,
        if (!codec)
                return -ENOMEM;
 
+       mutex_init(&codec->widget_lock);
+
        sprintf(name, "hdaudioC%dD%d", card->number, codec_addr);
        err = snd_hdac_device_init(&codec->core, &bus->core, name, codec_addr);
        if (err < 0) {
-- 
2.17.1

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