Re: [PATCH net-next v4 0/7] bonding: Extend arp_ip_target format to allow for a list of vlan tags.

[Jakub Kicinski <kuba@kernel.org>]

On Fri, 27 Jun 2025 13:17:13 -0700 David Wilder wrote:
> The current implementation of the arp monitor builds a list of vlan-tags by
> following the chain of net_devices above the bond. See bond_verify_device_path().
> Unfortunately, with some configurations, this is not possible. One example is
> when an ovs switch is configured above the bond.
> 
> This change extends the "arp_ip_target" parameter format to allow for a list of
> vlan tags to be included for each arp target. This new list of tags is optional
> and may be omitted to preserve the current format and process of discovering
> vlans.
> 
> The new format for arp_ip_target is:
> arp_ip_target ipv4-address[vlan-tag\...],...
> 
> For example:
> arp_ip_target 10.0.0.1[10/20]
> arp_ip_target 10.0.0.1[] (used to disable vlan discovery)
> 
> The extended format of arp_ip_target is only supported by using the ip command when
> creating the bond. Module parameters and the sysfs file do not allow the use of the
> extended format.
> 
> Changes since V3:
> 
> 1) Moved the parsing of the extended arp_ip_target out of the kernel and into
>    userspace (ip command). A separate patch to iproute2 to follow shortly.
> 2) Split up the patch set to make review easier.

This appears to trigger the following warning when running the newly
added tests (BTW please run shellcheck on the test, too):

[ 1315.127007][ T9889] WARNING: CPU: 2 PID: 9889 at lib/vsprintf.c:2802 vsnprintf+0xa76/0x1050
[ 1315.127471][ T9889] Modules linked in: [last unloaded: netdevsim]
[ 1315.127908][ T9889] CPU: 2 UID: 0 PID: 9889 Comm: grep Not tainted 6.16.0-rc3-virtme #1 PREEMPT(full) 
[ 1315.128709][ T9889] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1315.129070][ T9889] RIP: 0010:vsnprintf+0xa76/0x1050
[ 1315.129378][ T9889] Code: 01 89 44 24 50 83 e8 01 89 44 24 7c 85 c0 7f c2 4c 89 f8 48 c1 e8 03 42 0f b6 04 08 84 c0 0f 85 72 fa ff ff e9 75 fa ff ff 90 <0f> 0b 90 e9 f1 f7 ff ff 48 8b 44 24 28 80 38 00 0f 85 a7 04 00 00
[ 1315.130388][ T9889] RSP: 0018:ffffc90001227970 EFLAGS: 00010286
[ 1315.130749][ T9889] RAX: 0000000000000000 RBX: fffff52000244f4c RCX: ffffc90001227a80
[ 1315.131233][ T9889] RDX: ffffffffb80db4e0 RSI: ffffffffffffffff RDI: 1ffff92000244f39
[ 1315.131654][ T9889] RBP: ffffc90001227a50 R08: ffffffffb80db4a1 R09: ffffffffb6e54d12
[ 1315.132073][ T9889] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[ 1315.132509][ T9889] R13: 000000000000000c R14: ffffffffb6e54ce0 R15: ffffc90001227ba0
[ 1315.132937][ T9889] FS:  00007f554d21e740(0000) GS:ffff88807bb4d000(0000) knlGS:0000000000000000
[ 1315.133437][ T9889] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1315.133794][ T9889] CR2: 000055c1198c67f8 CR3: 000000000ca1b001 CR4: 0000000000772ef0
[ 1315.134244][ T9889] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1315.134968][ T9889] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1315.135406][ T9889] PKRU: 55555554
[ 1315.135626][ T9889] Call Trace:
[ 1315.135843][ T9889]  <TASK>
[ 1315.136005][ T9889]  ? __pfx_vsnprintf+0x10/0x10
[ 1315.136310][ T9889]  ? __pfx_bond_opt_parse+0x10/0x10
[ 1315.136602][ T9889]  snprintf+0xa1/0xd0
[ 1315.136823][ T9889]  ? __pfx_snprintf+0x10/0x10
[ 1315.137133][ T9889]  ? bond_opt_parse+0x32/0x6e0
[ 1315.137414][ T9889]  ? bond_opt_parse+0x30/0x6e0
[ 1315.137696][ T9889]  bond_info_show_master+0x84c/0x1140
[ 1315.137977][ T9889]  ? bond_opt_parse+0x32/0x6e0
[ 1315.138276][ T9889]  ? __pfx_bond_info_show_master+0x10/0x10
[ 1315.138625][ T9889]  ? __pfx_seq_printf+0x10/0x10
[ 1315.138917][ T9889]  ? __pfx_bond_info_seq_start+0x10/0x10
[ 1315.139218][ T9889]  bond_info_seq_show+0x43/0x50
[ 1315.139507][ T9889]  seq_read_iter+0x40e/0x1090
[ 1315.139805][ T9889]  proc_reg_read_iter+0x1a3/0x270
[ 1315.140100][ T9889]  vfs_read+0x75a/0xce0
[ 1315.140324][ T9889]  ? vfs_getattr_nosec+0x2c0/0x3e0
[ 1315.140608][ T9889]  ? __pfx_vfs_read+0x10/0x10
[ 1315.140896][ T9889]  ? __do_sys_newfstat+0x7b/0xc0
[ 1315.141201][ T9889]  ksys_read+0xf7/0x1d0
-- 
pw-bot: cr