On Tue, Jul 02, 2019 at 05:51:39PM +0200, Nicolas Dichtel wrote:
> The following commands produce a backtrace and return an error but the xfrm
> interface is created (in the wrong netns):
> $ ip netns add foo
> $ ip netns add bar
> $ ip -n foo netns set bar 0
> $ ip -n foo link add xfrmi0 link-netnsid 0 type xfrm dev lo if_id 23
> RTNETLINK answers: Invalid argument
> $ ip -n bar link ls xfrmi0
> 2: xfrmi0@lo: <NOARP,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT
> group default qlen 1000
> link/none 00:00:00:00:00:00 brd 00:00:00:00:00:00
>
> Here is the backtrace:
> [ 79.879174] WARNING: CPU: 0 PID: 1178 at net/core/dev.c:8172
> rollback_registered_many+0x86/0x3c1
> [ 79.880260] Modules linked in: xfrm_interface nfsv3 nfs_acl auth_rpcgss
> nfsv4 nfs lockd grace sunrpc fscache button parport_pc parport serio_raw
> evdev pcspkr loop ext4 crc16 mbcache jbd2 crc32c_generic ide_cd_mod
> ide_gd_mod cdrom ata_$
> eneric ata_piix libata scsi_mod 8139too piix psmouse i2c_piix4 ide_core
> 8139cp mii i2c_core floppy
> [ 79.883698] CPU: 0 PID: 1178 Comm: ip Not tainted 5.2.0-rc6+ #106
> [ 79.884462] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 1.10.2-1 04/01/2014
> [ 79.885447] RIP: 0010:rollback_registered_many+0x86/0x3c1
> [ 79.886120] Code: 01 e8 d7 7d c6 ff 0f 0b 48 8b 45 00 4c 8b 20 48 8d 58 90
> 49 83 ec 70 48 8d 7b 70 48 39 ef 74 44 8a 83 d0 04 00 00 84 c0 75 1f <0f> 0b
> e8 61 cd ff ff 48 b8 00 01 00 00 00 00 ad de 48 89 43 70 66
> [ 79.888667] RSP: 0018:ffffc900015ab740 EFLAGS: 00010246
> [ 79.889339] RAX: ffff8882353e5700 RBX: ffff8882353e56a0 RCX:
> ffff8882353e5710
> [ 79.890174] RDX: ffffc900015ab7e0 RSI: ffffc900015ab7e0 RDI:
> ffff8882353e5710
> [ 79.891029] RBP: ffffc900015ab7e0 R08: ffffc900015ab7e0 R09:
> ffffc900015ab7e0
> [ 79.891866] R10: ffffc900015ab7a0 R11: ffffffff82233fec R12:
> ffffc900015ab770
> [ 79.892728] R13: ffffffff81eb7ec0 R14: ffff88822ed6cf00 R15:
> 00000000ffffffea
> [ 79.893557] FS: 00007ff350f31740(0000) GS:ffff888237a00000(0000)
> knlGS:0000000000000000
> [ 79.894581] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 79.895317] CR2: 00000000006c8580 CR3: 000000022c272000 CR4:
> 00000000000006f0
> [ 79.896137] Call Trace:
> [ 79.896464] unregister_netdevice_many+0x12/0x6c
> [ 79.896998] __rtnl_newlink+0x6e2/0x73b
> [ 79.897446] ? __kmalloc_node_track_caller+0x15e/0x185
> [ 79.898039] ? pskb_expand_head+0x5f/0x1fe
> [ 79.898556] ? stack_access_ok+0xd/0x2c
> [ 79.899009] ? deref_stack_reg+0x12/0x20
> [ 79.899462] ? stack_access_ok+0xd/0x2c
> [ 79.899927] ? stack_access_ok+0xd/0x2c
> [ 79.900404] ? __module_text_address+0x9/0x4f
> [ 79.900910] ? is_bpf_text_address+0x5/0xc
> [ 79.901390] ? kernel_text_address+0x67/0x7b
> [ 79.901884] ? __kernel_text_address+0x1a/0x25
> [ 79.902397] ? unwind_get_return_address+0x12/0x23
> [ 79.903122] ? __cmpxchg_double_slab.isra.37+0x46/0x77
> [ 79.903772] rtnl_newlink+0x43/0x56
> [ 79.904217] rtnetlink_rcv_msg+0x200/0x24c
>
> In fact, each time a xfrm interface was created, a netdev was allocated
> by __rtnl_newlink()/rtnl_create_link() and then another one by
> xfrmi_newlink()/xfrmi_create(). Only the second one was registered, it's
> why the previous commands produce a backtrace: dev_change_net_namespace()
> was called on a netdev with reg_state set to NETREG_UNINITIALIZED (the
> first one).
>
> CC: Lorenzo Colitti <lore...@google.com>
> CC: Benedict Wong <benedictw...@google.com>
> CC: Steffen Klassert <steffen.klass...@secunet.com>
> CC: Shannon Nelson <shannon.nel...@oracle.com>
> CC: Antony Antony <ant...@phenome.org>
> CC: Eyal Birger <eyal.bir...@gmail.com>
> Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
> Reported-by: Julien Floret <julien.flo...@6wind.com>
> Signed-off-by: Nicolas Dichtel <nicolas.dich...@6wind.com>
Applied, thanks a lot!
