From: Dan Carpenter <dan.carpenter@oracle.com> To: Dongliang Mu <mudongliangabcd@gmail.com> Cc: perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com Subject: Re: [PATCH v2] ALSA: control led: fix memory leak in snd_ctl_led_register Date: Wed, 2 Jun 2021 09:35:43 +0300 [thread overview] Message-ID: <20210602063543.GB10983@kadam> (raw) In-Reply-To: <20210602034136.2762497-1-mudongliangabcd@gmail.com> 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
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com> To: Dongliang Mu <mudongliangabcd@gmail.com> Cc: syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com, linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org, tiwai@suse.com Subject: Re: [PATCH v2] ALSA: control led: fix memory leak in snd_ctl_led_register Date: Wed, 2 Jun 2021 09:35:43 +0300 [thread overview] Message-ID: <20210602063543.GB10983@kadam> (raw) In-Reply-To: <20210602034136.2762497-1-mudongliangabcd@gmail.com> 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
next prev parent reply other threads:[~2021-06-02 6:37 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-02 3:41 [PATCH v2] ALSA: control led: fix memory leak in snd_ctl_led_register Dongliang Mu 2021-06-02 6:35 ` Dan Carpenter [this message] 2021-06-02 6:35 ` Dan Carpenter 2021-06-02 6:47 ` Jaroslav Kysela 2021-06-02 6:59 ` Takashi Iwai 2021-06-02 6:59 ` Takashi Iwai
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