From: Jouni Hogander <jouni.hogander@unikie.com> Dev_hold has to be called always in rx_queue_add_kobject. Otherwise usage count drops below 0 in case of failure in kobject_init_and_add. Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject") Reported-by: Hulk Robot <hulkci@huawei.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Miller <davem@davemloft.net> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com> --- net/core/net-sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 5c4624298996..4c826b8bf9b1 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -919,14 +919,17 @@ static int rx_queue_add_kobject(struct net_device *dev, int index) struct kobject *kobj = &queue->kobj; int error = 0; + /* Kobject_put later will trigger rx_queue_release call which + * decreases dev refcount: Take that reference here + */ + dev_hold(queue->dev); + kobj->kset = dev->queues_kset; error = kobject_init_and_add(kobj, &rx_queue_ktype, NULL, "rx-%u", index); if (error) goto err; - dev_hold(queue->dev); - if (dev->sysfs_rx_queue_group) { error = sysfs_create_group(kobj, dev->sysfs_rx_queue_group); if (error) -- 2.17.1
On 2019/12/17 17:44, jouni.hogander@unikie.com wrote:
> From: Jouni Hogander <jouni.hogander@unikie.com>
>
> Dev_hold has to be called always in rx_queue_add_kobject.
> Otherwise usage count drops below 0 in case of failure in
> kobject_init_and_add.
>
> Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject")
> Reported-by: Hulk Robot <hulkci@huawei.com>
This bug was originally reported by
syzbot <syzbot+30209ea299c09d8785c9@syzkaller.appspotmail.com>
and forwarded by me. Who is "Hulk Robot <hulkci@huawei.com>" ?
From: Jouni Hogander <jouni.hogander@unikie.com> Dev_hold has to be called always in rx_queue_add_kobject. Otherwise usage count drops below 0 in case of failure in kobject_init_and_add. Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject") Reported-by: syzbot <syzbot+30209ea299c09d8785c9@syzkaller.appspotmail.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Miller <davem@davemloft.net> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com> --- net/core/net-sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 5c4624298996..4c826b8bf9b1 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -919,14 +919,17 @@ static int rx_queue_add_kobject(struct net_device *dev, int index) struct kobject *kobj = &queue->kobj; int error = 0; + /* Kobject_put later will trigger rx_queue_release call which + * decreases dev refcount: Take that reference here + */ + dev_hold(queue->dev); + kobj->kset = dev->queues_kset; error = kobject_init_and_add(kobj, &rx_queue_ktype, NULL, "rx-%u", index); if (error) goto err; - dev_hold(queue->dev); - if (dev->sysfs_rx_queue_group) { error = sysfs_create_group(kobj, dev->sysfs_rx_queue_group); if (error) -- 2.17.1
From: jouni.hogander@unikie.com
Date: Tue, 17 Dec 2019 10:44:29 +0200
> From: Jouni Hogander <jouni.hogander@unikie.com>
>
> Dev_hold has to be called always in rx_queue_add_kobject.
> Otherwise usage count drops below 0 in case of failure in
> kobject_init_and_add.
>
> Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: David Miller <davem@davemloft.net>
> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com>
Why are you posting this again, the change is already in my tree?
David Miller wrote:
> From: jouni.hogander@unikie.com
> Date: Tue, 17 Dec 2019 10:44:29 +0200
>
> > From: Jouni Hogander <jouni.hogander@unikie.com>
> >
> > Dev_hold has to be called always in rx_queue_add_kobject.
> > Otherwise usage count drops below 0 in case of failure in
> > kobject_init_and_add.
> >
> > Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject")
> > Reported-by: Hulk Robot <hulkci@huawei.com>
> > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> > Cc: David Miller <davem@davemloft.net>
> > Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> > Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com>
>
> Why are you posting this again, the change is already in my tree?
>
Not posting again. Previous patch was for "netdev_queue_add_kobject" and
this patch is for "rx_queue_add_kobject". Also, Reported-by: in this patch
is wrong. Please apply an updated patch shown below.
Date: Tue, 17 Dec 2019 13:46:34 +0200
Message-Id: <20191217114634.9428-1-jouni.hogander@unikie.com>
From: jouni.hogander@unikie.com
Date: Tue, 17 Dec 2019 13:46:34 +0200
> From: Jouni Hogander <jouni.hogander@unikie.com>
>
> Dev_hold has to be called always in rx_queue_add_kobject.
> Otherwise usage count drops below 0 in case of failure in
> kobject_init_and_add.
>
> Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject")
> Reported-by: syzbot <syzbot+30209ea299c09d8785c9@syzkaller.appspotmail.com>
> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: David Miller <davem@davemloft.net>
> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com>
Applied and queued up for -stable.