[PATCH] : net : hso : do not call unregister_netdev if not registered

[PATCH] : net : hso : do not call unregister_netdev if not registered

[Yavuz, Tuba]

On an error path inside the hso_create_net_device function of the hso 
driver, hso_free_net_device gets called. This causes potentially a 
negative reference count in the net device if register_netdev has not 
been called yet as hso_free_net_device calls unregister_netdev 
regardless. I think the driver should distinguish these cases and call 
unregister_netdev only if register_netdev has been called.

Reported-by: Tuba Yavuz <tuba@ece.ufl.edu>
Signed-off-by: Tuba Yavuz <tuba@ece.ufl.edu>
---

--- drivers/net/usb/hso.c.orig	2019-01-27 14:45:58.232683119 -0500
+++ drivers/net/usb/hso.c	2019-01-27 14:47:43.592683629 -0500
@@ -2377,7 +2377,7 @@ static void hso_free_net_device(struct h
 
 	remove_net_device(hso_net->parent);
 
-	if (hso_net->net)
+	if (hso_net->net && hso_net->net->reg_state == NETREG_REGISTERED)
 		unregister_netdev(hso_net->net);
 
 	/* start freeing */

Re: [PATCH] : net : hso : do not call unregister_netdev if not registered

[David Miller]

From: "Yavuz, Tuba" <tuba@ece.ufl.edu>
Date: Mon, 28 Jan 2019 16:28:38 +0000

> On an error path inside the hso_create_net_device function of the hso 
> driver, hso_free_net_device gets called. This causes potentially a 
> negative reference count in the net device if register_netdev has not 
> been called yet as hso_free_net_device calls unregister_netdev 
> regardless. I think the driver should distinguish these cases and call 
> unregister_netdev only if register_netdev has been called.
> 
> Reported-by: Tuba Yavuz <tuba@ece.ufl.edu>
> Signed-off-by: Tuba Yavuz <tuba@ece.ufl.edu>

This does not apply cleanly to the net tree.

Also, please stop putting those spaces after the subsystem prefixes
in your Subject line.  Put the colon character immediately after
each subsystem prefix.

Thank you.

Re: [PATCH] : net : hso : do not call unregister_netdev if not registered

[Yavuz, Tuba]

Hi David,

I'll fix the spaces in the subject.

When I checked my patch it only had a p0 patch warning but I am not sure how to fix it. 

WARNING: patch prefix 'drivers' exists, appears to be a -p0 patch

total: 0 errors, 1 warnings, 0 checks, 8 lines checked

drivers/net/usb/hso.patch has style problems, please review.

So, please advise.

Best,


Tuba Yavuz, Ph.D.
Assistant Professor
Electrical and Computer Engineering Department
University of Florida
Gainesville, FL 32611
Webpage: http://www.tuba.ece.ufl.edu/
Email: tuba@ece.ufl.edu
Phone: (352) 846 0202

________________________________________
From: David Miller <davem@davemloft.net>
Sent: Wednesday, January 30, 2019 4:58 PM
To: Yavuz, Tuba
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] : net : hso : do not call unregister_netdev if not registered

From: "Yavuz, Tuba" <tuba@ece.ufl.edu>
Date: Mon, 28 Jan 2019 16:28:38 +0000

> On an error path inside the hso_create_net_device function of the hso
> driver, hso_free_net_device gets called. This causes potentially a
> negative reference count in the net device if register_netdev has not
> been called yet as hso_free_net_device calls unregister_netdev
> regardless. I think the driver should distinguish these cases and call
> unregister_netdev only if register_netdev has been called.
>
> Reported-by: Tuba Yavuz <tuba@ece.ufl.edu>
> Signed-off-by: Tuba Yavuz <tuba@ece.ufl.edu>

This does not apply cleanly to the net tree.

Also, please stop putting those spaces after the subsystem prefixes
in your Subject line.  Put the colon character immediately after
each subsystem prefix.

Thank you.