Date:   Mon, 18 Feb 2019 18:11:27 +0100
From:   "Frank Wunderlich" <frank-w@...lic-files.de>
To:     "Florian Fainelli" <f.fainelli@...il.com>
Cc:     netdev@...r.kernel.org, "Andrew Lunn" <andrew@...n.ch>,
        "Vivien Didelot" <vivien.didelot@...il.com>
Subject: Aw: Re: [BUG] [FIX] net: dsa: oops in br_vlan_enabled

Hi,

tried your Patch but crashes the same way:

[  107.416972] [<bf0fde88>] (br_vlan_enabled [bridge]) from [<bf14e234>] (dsa_po
rt_vlan_add+0x60/0xbc [dsa_core])                                               
[  107.426939] [<bf14e234>] (dsa_port_vlan_add [dsa_core]) from [<bf14eba4>] (ds
a_slave_port_obj_add+0x64/0x68 [dsa_core])                                      
[  107.437666] [<bf14eba4>] (dsa_slave_port_obj_add [dsa_core]) from [<c0b4e684>
] (__switchdev_port_obj_add+0x50/0xc4)                                          
[  107.448029] [<c0b4e684>] (__switchdev_port_obj_add) from [<c0b4e6d4>] (__swit
chdev_port_obj_add+0xa0/0xc4)                                                   
[  107.457612] [<c0b4e6d4>] (__switchdev_port_obj_add) from [<c0b4e758>] (switch
dev_port_obj_add_now+0x60/0x130)                                                
[  107.467453] [<c0b4e758>] (switchdev_port_obj_add_now) from [<c0b4eb94>] (swit
chdev_port_obj_add+0x44/0x190)                                                  
[  107.477181] [<c0b4eb94>] (switchdev_port_obj_add) from [<bf1013d0>] (br_switc
hdev_port_vlan_add+0x60/0x7c [bridge])                                          
[  107.487644] [<bf1013d0>] (br_switchdev_port_vlan_add [bridge]) from [<bf0ff25
0>] (__vlan_add+0xb0/0x620 [bridge])

regards Frank


> Gesendet: Montag, 18. Februar 2019 um 00:20 Uhr
> Von: "Florian Fainelli" <f.fainelli@...il.com>
> An: "Frank Wunderlich" <frank-w@...lic-files.de>, netdev@...r.kernel.org, "Andrew Lunn" <andrew@...n.ch>, "Vivien Didelot" <vivien.didelot@...il.com>
> Betreff: Re: [BUG] [FIX] net: dsa: oops in br_vlan_enabled
>
> 
> 
> On 2/17/2019 9:13 AM, Florian Fainelli wrote:
> > Hi Frank,
> > 
> > On 2/16/2019 8:22 AM, Frank Wunderlich wrote:
> >> Hi,
> >>
> >> i've found an oops in 4.19.23/10, seems to be fixed anyhow in 5.0 (also works in 4.14.101)
> >>
> >> root@...-r2:~# ip link add link lan0 name lan0.5 type vlan id 5
> >> root@...-r2:~# ip addr add 192.168.5.200/24 brd 192.168.5.255 dev lan0.5
> >> root@...-r2:~# ip link set dev lan0 up
> >> root@...-r2:~# ip link set dev lan0.5 up
> > 
> > So that these steps don't involve a bridge, and because we don't (yet)
> > implment ndo_vlan_rx_{add,kill}_vid() netdevice_ops, there is no VLAN
> > programming, it's all software
> > 
> >>
> >> 12: lan0.5@...0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state LOWERLAYERDOWN group default qlen 1000
> >>     link/ether 02:02:02:02:02:02 brd ff:ff:ff:ff:ff:ff
> >>     inet 192.168.5.200/24 brd 192.168.5.255 scope global lan0.5
> >>        valid_lft forever preferred_lft forever
> >>
> >> root@...-r2:~# brctl addbr bridge_name
> >> root@...-r2:~# brctl addif bridge_name lan0.5
> > 
> > Unless you changed the bridge to have VLAN filtering/awareness with:
> > 
> > echo 1 > /sys/class/net/bridge_name/bridge/vlan_filtering
> > 
> > There will be no VLAN configuration/objects pushed to DSA since commit
> > 2ea7a679ca2abd251c1ec03f20508619707e1749 ("net: dsa: Don't add vlans
> > when vlan filtering is disabled") so I am not sure how you got into that
> > situation because prior to pushing a VLAN object, the port must be part
> > of a bridge, so the steps typically look like:
> > 
> > - port_bridge_join which assigns dp->bridge_dev
> > - port_vlan_add
> > 
> > Does your 4.19.23 kernel somehow change how VLAN objects are pushed down
> > the switch driver?
> > 
> >> [  352.057128] bridge_name: port 1(lan0.5) entered blocking state
> >> [  352.063065] bridge_name: port 1(lan0.5) entered disabled state
> >> [  352.069181] device lan0.5 entered promiscuous mode
> >> [  352.074018] device lan0 entered promiscuous mode
> >> [  352.078906] Unable to handle kernel NULL pointer dereference at virtual address 00000558
> >> ...
> >> [  352.493085] [<bf0fde88>] (br_vlan_enabled [bridge]) from [<bf12c234>] (dsa_port_vlan_add+0x60/0xbc [dsa_core])
> >> [  352.503050] [<bf12c234>] (dsa_port_vlan_add [dsa_core]) from [<bf12cb64>] (dsa_slave_port_obj_add+0x4c/0x50 [dsa_core])
> >> [  352.513776] [<bf12cb64>] (dsa_slave_port_obj_add [dsa_core]) from [<c0b4e2d4>] (__switchdev_port_obj_add+0x50/0xc4)
> >> [  352.524138] [<c0b4e2d4>] (__switchdev_port_obj_add) from [<c0b4e324>] (__switchdev_port_obj_add+0xa0/0xc4)
> >> [  352.533721] [<c0b4e324>] (__switchdev_port_obj_add) from [<c0b4e3a8>] (switchdev_port_obj_add_now+0x60/0x130)
> >> [  352.543562] [<c0b4e3a8>] (switchdev_port_obj_add_now) from [<c0b4e7e4>] (switchdev_port_obj_add+0x44/0x190)
> >> [  352.553284] [<c0b4e7e4>] (switchdev_port_obj_add) from [<bf1013d0>] (br_switchdev_port_vlan_add+0x60/0x7c [bridge])
> >> [  352.563733] [<bf1013d0>] (br_switchdev_port_vlan_add [bridge]) from [<bf0ff250>] (__vlan_add+0xb0/0x620 [bridge])
> >> [  352.574007] [<bf0ff250>] (__vlan_add [bridge]) from [<bf0ffd04>] (nbp_vlan_add+0xc4/0x150 [bridge])
> >> [  352.583073] [<bf0ffd04>] (nbp_vlan_add [bridge]) from [<bf0ffec4>] (nbp_vlan_init+0x134/0x164 [bridge])
> >> [  352.592482] [<bf0ffec4>] (nbp_vlan_init [bridge]) from [<bf0edd4c>] (br_add_if+0x40c/0x5fc [bridge])
> >> [  352.601632] [<bf0edd4c>] (br_add_if [bridge]) from [<bf0eeb14>] (add_del_if+0x6c/0x80 [bridge])
> >> [  352.610351] [<bf0eeb14>] (add_del_if [bridge]) from [<bf0ef5b0>] (br_dev_ioctl+0x7c/0x9c [bridge])
> >> [  352.619290] [<bf0ef5b0>] (br_dev_ioctl [bridge]) from [<c09583d4>] (dev_ifsioc+0x184/0x324)
> >> [  352.627582] [<c09583d4>] (dev_ifsioc) from [<c09589e8>] (dev_ioctl+0x32c/0x5cc)
> >> [  352.634837] [<c09589e8>] (dev_ioctl) from [<c090913c>] (sock_ioctl+0x3bc/0x580)
> >>
> >>
> >> since my 4.19.23 kernel is modified a bit i tried with 4.19.10 without my net modifications and it is still reproducable with steps above (create a vlan on dsa-user-port and then use it in a bridge)
> >>
> >> i fixed it with these changes:
> 
> Your fix is undoing the commit from Andrew I just referenced, so it is
> definitively not the right fix because it will push VLAN objects down to
> a non-VLAN aware bridge, not that this is really a problem, but it
> should not be happening anyway.
> 
> The problem appears to be the following though: you are enslaving a VLAN
> device, which does not have switchdev_ops, so we recurse into the lower
> device, which is the DSA network device, which does have switchdev_ops
> defined. Once we are there we check the orig_dev against being a bridge
> master network device, but we are not checking that it's a VLAN device
> so we end-up assuming it is a DSA network device, we de-reference
> garbage by checking br_vlan_enabled(dp->bridge_dev) because there is
> simply no such data structure associated with the VLAN device.
> 
> The attached patch should help.
> 
> This is no longer a problem in newer kernels because the switchdev
> operations use a notifier which checks the target network device to be DSA.
> -- 
> Florian
> 

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