Commit 4f65ebcf authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Greg Kroah-Hartman

driver core: Don't ignore class_dir_create_and_add() failure.

commit 84d0c27d6233a9ba0578b20f5a09701eb66cee42 upstream.

syzbot is hitting WARN() at kernfs_add_one() [1].
This is because kernfs_create_link() is confused by previous device_add()
call which continued without setting dev->kobj.parent field when
get_device_parent() failed by memory allocation fault injection.
Fix this by propagating the error from class_dir_create_and_add() to
the calllers of get_device_parent().

[1] https://syzkaller.appspot.com/bug?id=fae0fb607989ea744526d1c082a5b8de6529116fSigned-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: default avatarsyzbot <syzbot+df47f81c226b31d89fb1@syzkaller.appspotmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e45ab2d6
......@@ -759,7 +759,7 @@ class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
dir = kzalloc(sizeof(*dir), GFP_KERNEL);
if (!dir)
return NULL;
return ERR_PTR(-ENOMEM);
dir->class = class;
kobject_init(&dir->kobj, &class_dir_ktype);
......@@ -769,7 +769,7 @@ class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
if (retval < 0) {
kobject_put(&dir->kobj);
return NULL;
return ERR_PTR(retval);
}
return &dir->kobj;
}
......@@ -1076,6 +1076,10 @@ int device_add(struct device *dev)
parent = get_device(dev->parent);
kobj = get_device_parent(dev, parent);
if (IS_ERR(kobj)) {
error = PTR_ERR(kobj);
goto parent_error;
}
if (kobj)
dev->kobj.parent = kobj;
......@@ -1174,6 +1178,7 @@ done:
kobject_del(&dev->kobj);
Error:
cleanup_glue_dir(dev, glue_dir);
parent_error:
put_device(parent);
name_error:
kfree(dev->p);
......@@ -1991,6 +1996,11 @@ int device_move(struct device *dev, struct device *new_parent,
device_pm_lock();
new_parent = get_device(new_parent);
new_parent_kobj = get_device_parent(dev, new_parent);
if (IS_ERR(new_parent_kobj)) {
error = PTR_ERR(new_parent_kobj);
put_device(new_parent);
goto out;
}
pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
__func__, new_parent ? dev_name(new_parent) : "<NULL>");
......
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