==================================================================
BUG: KASAN: slab-use-after-free in __mutex_lock+0x147/0x1350
Read of size 8 at addr ffff8881616b24b0 by task kworker/u8:3/5836

CPU: 1 UID: 0 PID: 5836 Comm: kworker/u8:3 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+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 13369:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x411/0x7f0
 udp_tunnel_nic_netdevice_event+0x4c3/0x1810
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 nsim_create+0xb3f/0x1050
 __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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13371:
 kasan_save_track+0x3e/0x80
 __kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x19a/0x6d0
 udp_tunnel_nic_netdevice_event+0x11ab/0x1810
 notifier_call_chain+0x1b6/0x3e0
 unregister_netdevice_many_notify+0x1860/0x2390
 unregister_netdevice_queue+0x33c/0x380
 nsim_destroy+0x1e5/0x680
 __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/0xfa0
 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+0xdff/0x1810
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 nsim_create+0xb3f/0x1050
 __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/0xfa0
 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+0xdff/0x1810
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 nsim_create+0xb3f/0x1050
 __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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8881616b2400
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 176 bytes inside of
 freed 256-byte region [ffff8881616b2400, ffff8881616b2500)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1616b2
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff888100041b40 ffffea0005ce3280 dead000000000004
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff888100041b40 ffffea0005ce3280 dead000000000004
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 057ff00000000001 ffffea000585ac81 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 5950, tgid 5949 (syz.1.18), ts 60365471095, free_ts 60335113879
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x2365/0x2440
 __alloc_frozen_pages_noprof+0x181/0x370
 allocate_slab+0x71/0x3a0
 ___slab_alloc+0xe94/0x18a0
 __slab_alloc+0x65/0x100
 __kmalloc_node_noprof+0x5cc/0x800
 allocate_slab+0x179/0x3a0
 ___slab_alloc+0xe94/0x18a0
 __slab_alloc+0x65/0x100
 __kvmalloc_node_noprof+0x6ba/0x910
 alloc_fdtable+0x169/0x2c0
 dup_fd+0x86c/0xb60
 ksys_unshare+0x450/0x8c0
 __x64_sys_unshare+0x38/0x50
 do_syscall_64+0xfa/0xfa0
page last free pid 47 tgid 47 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 rcu_core+0xcab/0x1770
 handle_softirqs+0x286/0x870
 do_softirq+0xec/0x180
 __local_bh_enable_ip+0x17d/0x1c0
 ipv6_get_lladdr+0x2aa/0x3f0
 mld_newpack+0x420/0xc40
 add_grhead+0x5a/0x2a0
 add_grec+0x1452/0x1740
 mld_send_initial_cr+0x288/0x550
 mld_dad_work+0x46/0x490
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30

Memory state around the buggy address:
 ffff8881616b2380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881616b2400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881616b2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8881616b2500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881616b2580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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