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* [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject
@ 2019-12-17  8:44 jouni.hogander
  2019-12-17 11:09 ` Tetsuo Handa
  2019-12-17 22:20 ` David Miller
  0 siblings, 2 replies; 6+ messages in thread
From: jouni.hogander @ 2019-12-17  8:44 UTC (permalink / raw)
  To: netdev; +Cc: Jouni Hogander, Tetsuo Handa, David Miller, Lukas Bulwahn

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


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject
  2019-12-17  8:44 [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject jouni.hogander
@ 2019-12-17 11:09 ` Tetsuo Handa
  2019-12-17 22:20 ` David Miller
  1 sibling, 0 replies; 6+ messages in thread
From: Tetsuo Handa @ 2019-12-17 11:09 UTC (permalink / raw)
  To: jouni.hogander, netdev; +Cc: David Miller, Lukas Bulwahn

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>" ?

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject
  2019-12-17  8:44 [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject jouni.hogander
  2019-12-17 11:09 ` Tetsuo Handa
@ 2019-12-17 22:20 ` David Miller
  2019-12-18  1:36   ` Tetsuo Handa
  1 sibling, 1 reply; 6+ messages in thread
From: David Miller @ 2019-12-17 22:20 UTC (permalink / raw)
  To: jouni.hogander; +Cc: netdev, penguin-kernel, lukas.bulwahn

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?

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject
  2019-12-17 22:20 ` David Miller
@ 2019-12-18  1:36   ` Tetsuo Handa
  0 siblings, 0 replies; 6+ messages in thread
From: Tetsuo Handa @ 2019-12-18  1:36 UTC (permalink / raw)
  To: David Miller; +Cc: jouni.hogander, netdev, penguin-kernel, lukas.bulwahn

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>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject
  2019-12-17 11:46 jouni.hogander
@ 2019-12-18  6:57 ` David Miller
  0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2019-12-18  6:57 UTC (permalink / raw)
  To: jouni.hogander; +Cc: netdev, penguin-kernel, lukas.bulwahn

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.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject
@ 2019-12-17 11:46 jouni.hogander
  2019-12-18  6:57 ` David Miller
  0 siblings, 1 reply; 6+ messages in thread
From: jouni.hogander @ 2019-12-17 11:46 UTC (permalink / raw)
  To: netdev; +Cc: Jouni Hogander, Tetsuo Handa, David Miller, Lukas Bulwahn

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


^ permalink raw reply	[flat|nested] 6+ messages in thread

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2019-12-17  8:44 [PATCH] net-sysfs: Call dev_hold always in rx_queue_add_kobject jouni.hogander
2019-12-17 11:09 ` Tetsuo Handa
2019-12-17 22:20 ` David Miller
2019-12-18  1:36   ` Tetsuo Handa
2019-12-17 11:46 jouni.hogander
2019-12-18  6:57 ` David Miller

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