Date: Wed, 18 Mar 2009 09:16:22 -0700 From: Julian Elischer <julian@elischer.org> To: Ash Gokhale <ash@aeria.net> Cc: freebsd-net@freebsd.org Subject: Re: netgraph modules won't unload after use Message-ID: <49C11E56.7090809@elischer.org> In-Reply-To: <6CBA0923-DAF1-4FD5-A670-F5888BCA47B1@aeria.net> References: <6CBA0923-DAF1-4FD5-A670-F5888BCA47B1@aeria.net>
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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@trafmon1:kldload ng_ether root@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@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@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@trafmon1:klunload ng_hole klunload: Command not found. root@trafmon1:kldunload ng_hole root@trafmon1:kldunload ng_ether kldunload: can't unload file: Device busy root@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@trafmon1: this is expected. ng-ether is not unloadable as the connections are too complicated to unwind easily.. one day.... root@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. > > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
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