=====================================================
BUG: KMSAN: uninit-value in __ipv6_dev_mc_dec+0x3c6/0xdd0 net/ipv6/mcast.c:974
 __ipv6_dev_mc_dec+0x3c6/0xdd0 net/ipv6/mcast.c:974
 addrconf_leave_solict net/ipv6/addrconf.c:2191 [inline]
 __ipv6_ifa_notify+0xbb5/0x1f90 net/ipv6/addrconf.c:6130
 addrconf_ifdown+0x19f6/0x2b90 net/ipv6/addrconf.c:3840
 addrconf_notify+0x2f7/0x1ce0
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x12b/0x2a0 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2002 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2014 [inline]
 call_netdevice_notifiers net/core/dev.c:2028 [inline]
 dev_close_many+0x738/0xb60 net/core/dev.c:1603
 vlan_device_event+0x267c/0x3570 net/8021q/vlan.c:450
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x12b/0x2a0 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2002 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2014 [inline]
 call_netdevice_notifiers net/core/dev.c:2028 [inline]
 dev_close_many+0x738/0xb60 net/core/dev.c:1603
 unregister_netdevice_many+0x8ea/0x31f0 net/core/dev.c:11054
 unregister_netdevice_queue+0x58c/0x740 net/core/dev.c:11011
 unregister_netdevice include/linux/netdevice.h:2989 [inline]
 __tun_detach+0x27dc/0x3350 drivers/net/tun.c:670
 tun_detach drivers/net/tun.c:687 [inline]
 tun_chr_close+0xda/0x1c0 drivers/net/tun.c:3402
 __fput+0x7c4/0x10a0 fs/file_table.c:280
 ____fput+0x37/0x40 fs/file_table.c:313
 task_work_run+0x173/0x2b0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x3f0/0x490 kernel/entry/common.c:176
 exit_to_user_mode_prepare kernel/entry/common.c:208 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x7e/0xc0 kernel/entry/common.c:302
 __do_fast_syscall_32+0xa5/0xf0 arch/x86/entry/common.c:183
 do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable maddr.i created at:
 addrconf_leave_solict net/ipv6/addrconf.c:2185 [inline]
 __ipv6_ifa_notify+0x95f/0x1f90 net/ipv6/addrconf.c:6130
 addrconf_ifdown+0x19f6/0x2b90 net/ipv6/addrconf.c:3840

CPU: 1 PID: 24067 Comm: syz-executor.1 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================