==================================================================
BUG: KASAN: slab-use-after-free in __mutex_lock+0x147/0x1350
Read of size 8 at addr ffff888026d32eb0 by task kworker/u8:1/13

CPU: 0 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: udp_tunnel_nic udp_tunnel_nic_device_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 __mutex_lock+0x147/0x1350
 udp_tunnel_nic_device_sync_work+0x39/0xa50
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 7003:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x27a/0x4f0
 udp_tunnel_nic_netdevice_event+0x854/0x19f0
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 nsim_create+0xae8/0xf10
 __nsim_dev_port_add+0x6b6/0xb10
 nsim_dev_port_add_all+0x37/0xf0
 nsim_dev_reload_up+0x451/0x780
 devlink_reload+0x4ec/0x8d0
 devlink_nl_reload_doit+0xb35/0xd50
 genl_family_rcv_msg_doit+0x215/0x300
 genl_rcv_msg+0x60e/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 7002:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kfree+0x18e/0x440
 udp_tunnel_nic_netdevice_event+0x1332/0x19f0
 notifier_call_chain+0x1b6/0x3e0
 unregister_netdevice_many_notify+0x14d7/0x1ff0
 unregister_netdevice_queue+0x33c/0x380
 nsim_destroy+0x1dd/0x670
 __nsim_dev_port_del+0x14d/0x1b0
 nsim_dev_reload_destroy+0x288/0x490
 nsim_dev_reload_down+0x8a/0xc0
 devlink_reload+0x1b6/0x8d0
 devlink_nl_reload_doit+0xb35/0xd50
 genl_family_rcv_msg_doit+0x215/0x300
 genl_rcv_msg+0x60e/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 insert_work+0x3d/0x330
 __queue_work+0xbaf/0xfb0
 queue_work_on+0x181/0x270
 __udp_tunnel_nic_add_port+0xb71/0xd60
 udp_tunnel_push_rx_port+0x180/0x200
 geneve_offload_rx_ports+0xd7/0x160
 geneve_netdevice_event+0x6a/0x80
 notifier_call_chain+0x1b6/0x3e0
 call_netdevice_notifiers+0x88/0xc0
 udp_tunnel_nic_netdevice_event+0x134d/0x19f0
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 nsim_create+0xae8/0xf10
 __nsim_dev_port_add+0x6b6/0xb10
 nsim_dev_port_add_all+0x37/0xf0
 nsim_dev_reload_up+0x451/0x780
 devlink_reload+0x4ec/0x8d0
 devlink_nl_reload_doit+0xb35/0xd50
 genl_family_rcv_msg_doit+0x215/0x300
 genl_rcv_msg+0x60e/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Second to last potentially related work creation:
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 insert_work+0x3d/0x330
 __queue_work+0xcd2/0xfb0
 queue_work_on+0x181/0x270
 __udp_tunnel_nic_add_port+0xb71/0xd60
 udp_tunnel_push_rx_port+0x180/0x200
 vxlan_offload_rx_ports+0x139/0x200
 vxlan_netdevice_event+0x111/0x470
 notifier_call_chain+0x1b6/0x3e0
 call_netdevice_notifiers+0x88/0xc0
 udp_tunnel_nic_netdevice_event+0x134d/0x19f0
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 nsim_create+0xae8/0xf10
 __nsim_dev_port_add+0x6b6/0xb10
 nsim_dev_port_add_all+0x37/0xf0
 nsim_dev_reload_up+0x451/0x780
 devlink_reload+0x4ec/0x8d0
 devlink_nl_reload_doit+0xb35/0xd50
 genl_family_rcv_msg_doit+0x215/0x300
 genl_rcv_msg+0x60e/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888026d32e00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 176 bytes inside of
 freed 256-byte region [ffff888026d32e00, ffff888026d32f00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26d32
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a441b40 ffffea00009c8c00 dead000000000003
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a441b40 ffffea00009c8c00 dead000000000003
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea00009b4c81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5847, tgid 5847 (syz-executor), ts 46954910656, free_ts 46918676139
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x370
 ___slab_alloc+0xbeb/0x1410
 __kmalloc_noprof+0x305/0x4f0
 __register_sysctl_table+0xba1/0x1340
 neigh_sysctl_register+0x9a2/0xa80
 addrconf_sysctl_register+0xb3/0x1c0
 addrconf_notify+0x82b/0x1010
 notifier_call_chain+0x1b6/0x3e0
 netif_change_name+0x5e9/0x960
 do_setlink+0x9f6/0x41c0
 rtnl_newlink+0x160b/0x1c70
 rtnetlink_rcv_msg+0x7cf/0xb70
page last free pid 5847 tgid 5847 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __slab_free+0x303/0x3c0
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 __kmalloc_cache_noprof+0x1be/0x3d0
 dropmon_net_event+0x221/0x2b0
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 nsim_create+0xae8/0xf10
 __nsim_dev_port_add+0x6b6/0xb10
 nsim_dev_port_add_all+0x37/0xf0
 nsim_drv_probe+0x88e/0xba0
 really_probe+0x26d/0x9e0
 __driver_probe_device+0x18c/0x2f0
 driver_probe_device+0x4f/0x430

Memory state around the buggy address:
 ffff888026d32d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888026d32e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888026d32e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888026d32f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888026d32f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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