Messages in this thread | | | Date | Wed, 2 Jun 2021 09:35:43 +0300 | From | Dan Carpenter <> | Subject | Re: [PATCH v2] ALSA: control led: fix memory leak in snd_ctl_led_register |
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On Wed, Jun 02, 2021 at 11:41:36AM +0800, 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.
(Hopefully it's clear to everyone that this is in the original code and fixed in your patch).
> > 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> > ---
Looks perfect to me!
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
regards, dan carpenter
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