netgraph modules won't unload after use
Ash Gokhale
ash at aeria.net
Mon Mar 23 10:20:22 PDT 2009
>
Thanks for looking at it Julian, I still can't figure out which
resource it needs to release before exiting.
I've replaced the raw ether_input routine on the interface to
continue my module until I can figure out what's wrong with my
netgraph glue.
Again this minimal module demonstrates the trouble, I'd appreciate it
if some sage could say "there's your trouble"
http://pastebin.com/m31b6ece6
> netgraph modules won't unload after use
> Julian Elischer julian at elischer.org
> Wed Mar 18 09:16:15 PDT 2009
>
> * Previous message: netgraph modules won't unload after use
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> panic
> * Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
>
> Ash Gokhale wrote:
> > I'm developing a kernel module that will be doing inspection and
> needed
> > access to raw network frames,
> > so I turned to netgraph as the solution.However it seems that
> netgraph
> > will not permit a module
> > to unload once it's participated in a mkpeer/connect operation.
> > Rebooting to remove a module is
> > angrymaking (not like mtx/sleep crashes).
> >
> > This going into the kernel because my bpf based userland stuff
> is
> > probably not going to hold up to the packet rate.
> >
> > Should I file a PR? Or is there magic in the documentation I
> havn't found?
> >
> >
> > I've observed the trouble in 7.0 release, and tonight's 7_RELENG,
> with
> > GENERIC + WITNESS/INVARIANTS
> >
> > The module code ( cobbled together from netgraph/ng_sample.c /
> ng_echo.c)
> > http://pastebin.com/m31b6ece6
> >
> > The module loads and unloads fine until connected to a netgraph
> hook:
>
> hmm they are supposed to, and they did in the past..
> let me check...
>
> root at trafmon1:kldload ng_ether
> root at trafmon1:ifconfig
> bge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0
> mtu 1500
> options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> ether 00:11:43:30:fb:8a
> inet 10.7.2.3 netmask 0xffffff00 broadcast 10.7.2.255
> media: Ethernet autoselect (100baseTX <full-duplex>)
> status: active
> bge1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
> options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> ether 00:11:43:30:fb:8b
> media: Ethernet autoselect (none)
> status: no carrier
> fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0
> mtu 1500
> options=b<RXCSUM,TXCSUM,VLAN_MTU>
> ether 00:0e:0c:62:aa:14
> inet 10.7.0.101 netmask 0xffffff00 broadcast 10.7.0.255
> media: Ethernet autoselect (100baseTX <full-duplex>)
> status: active
> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
> inet 127.0.0.1 netmask 0xff000000
> root at trafmon1:ngctl
> + list
> There are 4 total nodes:
> Name: bge0 Type: ether ID: 00000002 Num
> hooks: 0
> Name: bge1 Type: ether ID: 00000003 Num
> hooks: 0
> Name: ngctl4252 Type: socket ID: 00000005 Num
> hooks: 0
> Name: fxp0 Type: ether ID: 00000004 Num
> hooks: 0
> + mkpeer bge0: hole lower hook
> + list
> There are 5 total nodes:
> Name: <unnamed> Type: hole ID: 00000006 Num
> hooks: 1
> Name: bge0 Type: ether ID: 00000002 Num
> hooks: 1
> Name: bge1 Type: ether ID: 00000003 Num
> hooks: 0
> Name: ngctl4252 Type: socket ID: 00000005 Num
> hooks: 0
> Name: fxp0 Type: ether ID: 00000004 Num
> hooks: 0
> + shutdown [6]:
> + list
> There are 4 total nodes:
> Name: bge0 Type: ether ID: 00000002 Num
> hooks: 0
> Name: bge1 Type: ether ID: 00000003 Num
> hooks: 0
> Name: ngctl4252 Type: socket ID: 00000005 Num
> hooks: 0
> Name: fxp0 Type: ether ID: 00000004 Num
> hooks: 0
> + quit
> root at trafmon1:kldstat -v
> Id Refs Address Size Name
> 1 36 0xc0400000 6a9c28 kernel (/boot/kernel/kernel)
>
> [...]
>
> 7 1 0xccb16000 4000 ng_ether.ko (/boot/kernel/ng_ether.ko)
> Contains modules:
> Id Name
> 246 ng_ether
> 8 1 0xccb1b000 2000 ng_hole.ko (/boot/kernel/ng_hole.ko)
> Contains modules:
> Id Name
> 247 ng_hole
> root at trafmon1:klunload ng_hole
> klunload: Command not found.
> root at trafmon1:kldunload ng_hole
> root at trafmon1:kldunload ng_ether
> kldunload: can't unload file: Device busy
> root at trafmon1:kldstat -v
> Id Refs Address Size Name
> 1 36 0xc0400000 6a9c28 kernel (/boot/kernel/kernel)
>
> [...]
>
> 7 1 0xccb16000 4000 ng_ether.ko (/boot/kernel/ng_ether.ko)
> Contains modules:
> Id Name
> 246 ng_ether
> root at trafmon1:
>
>
> this is expected. ng-ether is not unloadable as the connections are
> too complicated to unwind easily.. one day....
>
> root at trafmon1:
>
> >> Stop in /root/tmp/food.ko.
> >> Exit 1
> >> #Mar 18 03:14:31 kernel: quiesced
> >> :ro:~/tmp/food.ko:3:14:31:32
> >> Mar 18 03:14:31 kernel: foodmod unloaded
> >
> >
> > Seems that I can't unload some of the other netgraph types either
> ( it's
> > not just me):
> >
> >> #kldunload ng_ether
> >> :ro:~/tmp/food.ko:3:24:07:41
> >> kldunload: can't unload file: Device busy
> >> Exit 1
>
> try unloading a node that IS unloadable..
>
> see the following comment in ng_ehter.c:
> /*
> * Note that the base code won't try to unload us until
> * all nodes have been removed, and that can't happen
> * until all Ethernet interfaces are removed. In any
> * case, we know there are no nodes left if the action
> * is MOD_UNLOAD, so there's no need to detach any nodes.
> */
>
> so we can't run this unless you have removeable ethernet interfaces,
> and have removed them.
>
>
>
> >
> >
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