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From:   Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To:     "RaghuramChary.Jallipalli@microchip.com" 
        <RaghuramChary.Jallipalli@microchip.com>
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Subject: Re: [PATCH] net: lan78xx: fix "enabled interrupts" warninig
Thread-Topic: [PATCH] net: lan78xx: fix "enabled interrupts" warninig
Thread-Index: AQHU7dHNU1pmmx19ukWi008Ht4Z+BqYx4peAgACJ84D//6iSAIABfFmAgAGQOQCAAAb8AIAKnOQAgABJ0IA=
Date:   Wed, 17 Apr 2019 08:22:07 +0000
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On Wed, 17 Apr 2019 03:49:46 +0000 <RaghuramChary.Jallipalli@microchip.com>=
 wrote:

>=20
> Hi Jisheng,

Hi,

>=20
> > > I want to understand if there is any functionality impact with this w=
arning? =20
> > Because I'm afraid if the current changes are removed we might hit some
> > other issues (or older ones). We have to go through rigorous testing be=
fore
> > going ahead.
> >
> > Warning indicates there's something wrong in the code. =20
>=20
> Agree that the code is incorrect. Just wanted to understand if you had an=
y functionality impact too.
>=20
> >
> > IMHO phy_mac_interrupt() and PHY_IGNORE_INTERRUPT is the correct
> > solution. If the phy_mac_interrupt() poll is fixed, I think maybe old i=
ssue
> > which commit cc89c323a30e want to fix won't exist.
> > =20
>=20
> I tried to reproduce the problem in PC environment but did not see the wa=
rnings.
> However, I tried your patch and did plug/unplug tests(rmmod/insmod contin=
uously) and observed call traces from kernel. I don't see these traces with=
out your patch.
> Attached log.

I believe this is another bug in lan78xx driver: after phy_disconnect() if
there's intr urb coming, we will call phy_mac_interrupt, so trigger
phy_state_machine(), but now the phydev->attached_dev is NULL, so NULL
pointer deference. Can you please try below patch:

--->8
diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 246a0d1bbc6c..27d6fbdd58c1 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3467,6 +3467,8 @@ static void lan78xx_disconnect(struct usb_interface *=
intf)
 	net =3D dev->net;
 	phydev =3D net->phydev;
=20
+	usb_kill_urb(dev->urb_intr);
+
 	phy_unregister_fixup_for_uid(PHY_KSZ9031RNX, 0xfffffff0);
 	phy_unregister_fixup_for_uid(PHY_LAN8835, 0xfffffff0);
=20
@@ -3483,7 +3485,6 @@ static void lan78xx_disconnect(struct usb_interface *=
intf)
=20
 	lan78xx_unbind(dev, intf);
=20
-	usb_kill_urb(dev->urb_intr);
 	usb_free_urb(dev->urb_intr);
=20
 	free_netdev(net);