Messages in this thread | | | Subject | Re: [PATCH v2] ALSA: control led: fix memory leak in snd_ctl_led_register | From | Jaroslav Kysela <> | Date | Wed, 2 Jun 2021 08:47:04 +0200 |
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On 02. 06. 21 5:41, Dongliang Mu wrote: > The snd_ctl_led_sysfs_add and snd_ctl_led_sysfs_remove should contain > the refcount operations in pair. However, snd_ctl_led_sysfs_remove fails > to decrease the refcount to zero, which causes device_release never to > be invoked. This leads to memory leak to some resources, like struct > device_private. In addition, we also free some other similar memory > leaks in snd_ctl_led_init/snd_ctl_led_exit. > > Fix this by replacing device_del to device_unregister > in snd_ctl_led_sysfs_remove/snd_ctl_led_init/snd_ctl_led_exit. > > Note that, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device will > call kobject_release and delay the release of kobject, which will cause > use-after-free when the memory backing the kobject is freed at once. > > Reported-by: syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com > Fixes: a135dfb5de1 ("ALSA: led control - add sysfs kcontrol LED marking layer") > Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Many thanks to you and Dan to cover this.
Revieved-by: Jaroslav Kysela <perex@perex.cz>
-- Jaroslav Kysela <perex@perex.cz> Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
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