Subject: Re: [PATCH net] vlan: Fix VLAN 0 memory leak

From: Vlad Buslov <[email-masked]>
Date: Mon, 31 Jul 2023 22:11:04 +0300

On Mon 31 Jul 2023 at 18:45, Ido Schimmel <[email-masked]> wrote:
> On Mon, Jul 31, 2023 at 11:52:19AM +0200, Simon Horman wrote:
>> perhaps it would be worth including the information added
>> by Ido above in the patch description. Not a hard requirement
>> from my side, just an idea.
>
> I agree (assuming my analysis is correct).

Sorry for making it more convoluted than necessary. Just disabling HW
vlan feature on the device and removing the module is enough for repro:

# modprobe 8021q
# ip l set dev eth2 up
# ethtool -K eth2 rx-vlan-filter off
# modprobe -r mlx5_ib
# modprobe -r mlx5_core
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff888103dcd900 (size 256):
  comm "ip", pid 1490, jiffies 4294907305 (age 325.364s)
  hex dump (first 32 bytes):
    00 80 5d 03 81 88 ff ff 00 00 00 00 00 00 00 00  ..].............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000899f3bb9>] kmalloc_trace+0x25/0x80
    [<000000002889a7a2>] vlan_vid_add+0xa0/0x210
    [<000000007177800e>] vlan_device_event+0x374/0x760 [8021q]
    [<000000009a0716b1>] notifier_call_chain+0x35/0xb0
    [<00000000bbf3d162>] __dev_notify_flags+0x58/0xf0
    [<0000000053d2b05d>] dev_change_flags+0x4d/0x60
    [<00000000982807e9>] do_setlink+0x28d/0x10a0
    [<0000000058c1be00>] __rtnl_newlink+0x545/0x980
    [<00000000e66c3bd9>] rtnl_newlink+0x44/0x70
    [<00000000a2cc5970>] rtnetlink_rcv_msg+0x29c/0x390
    [<00000000d307d1e4>] netlink_rcv_skb+0x54/0x100
    [<00000000259d16f9>] netlink_unicast+0x1f6/0x2c0
    [<000000007ce2afa1>] netlink_sendmsg+0x232/0x4a0
    [<00000000f3f4bb39>] sock_sendmsg+0x38/0x60
    [<000000002f9c0624>] ____sys_sendmsg+0x1e3/0x200
    [<00000000d6ff5520>] ___sys_sendmsg+0x80/0xc0
unreferenced object 0xffff88813354fde0 (size 32):
  comm "ip", pid 1490, jiffies 4294907305 (age 325.364s)
  hex dump (first 32 bytes):
    a0 d9 dc 03 81 88 ff ff a0 d9 dc 03 81 88 ff ff  ................
    81 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000899f3bb9>] kmalloc_trace+0x25/0x80
    [<000000002da64724>] vlan_vid_add+0xdf/0x210
    [<000000007177800e>] vlan_device_event+0x374/0x760 [8021q]
    [<000000009a0716b1>] notifier_call_chain+0x35/0xb0
    [<00000000bbf3d162>] __dev_notify_flags+0x58/0xf0
    [<0000000053d2b05d>] dev_change_flags+0x4d/0x60
    [<00000000982807e9>] do_setlink+0x28d/0x10a0
    [<0000000058c1be00>] __rtnl_newlink+0x545/0x980
    [<00000000e66c3bd9>] rtnl_newlink+0x44/0x70
    [<00000000a2cc5970>] rtnetlink_rcv_msg+0x29c/0x390
    [<00000000d307d1e4>] netlink_rcv_skb+0x54/0x100
    [<00000000259d16f9>] netlink_unicast+0x1f6/0x2c0
    [<000000007ce2afa1>] netlink_sendmsg+0x232/0x4a0
    [<00000000f3f4bb39>] sock_sendmsg+0x38/0x60
    [<000000002f9c0624>] ____sys_sendmsg+0x1e3/0x200
    [<00000000d6ff5520>] ___sys_sendmsg+0x80/0xc0