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BUG: KASAN: slab-use-after-free in __mutex_lock+0x157/0x1300
Read of size 8 at addr ffff88816aec2ab0 by task kworker/u8:2/5820

CPU: 1 UID: 0 PID: 5820 Comm: kworker/u8:2 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+0xe8/0x150
 print_report+0xba/0x230
 kasan_report+0x117/0x150
 __mutex_lock+0x157/0x1300
 udp_tunnel_nic_device_sync_work+0x39/0xa10
 process_scheduled_works+0xb02/0x1830
 worker_thread+0xa50/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 13072:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x35c/0x760
 udp_tunnel_nic_netdevice_event+0x4c3/0x17d0
 notifier_call_chain+0x1be/0x400
 register_netdevice+0x173a/0x1cf0
 nsim_create+0xb92/0x1100
 __nsim_dev_port_add+0x72a/0xb50
 nsim_dev_port_add_all+0x37/0xf0
 nsim_dev_reload_up+0x45f/0x7c0
 devlink_reload+0x505/0x8d0
 devlink_nl_reload_doit+0xaaa/0xc80
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x80f/0x9b0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0xa68/0xad0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13073:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c1/0x630
 udp_tunnel_nic_netdevice_event+0x11ed/0x17d0
 notifier_call_chain+0x1be/0x400
 unregister_netdevice_many_notify+0x186a/0x2370
 unregister_netdevice_queue+0x31f/0x360
 nsim_destroy+0x1e5/0x680
 __nsim_dev_port_del+0x14d/0x1b0
 nsim_dev_reload_destroy+0x288/0x490
 nsim_dev_reload_down+0x8a/0xc0
 devlink_reload+0x1d1/0x8d0
 devlink_nl_reload_doit+0xaaa/0xc80
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x80f/0x9b0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0xa68/0xad0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x14d/0xf80
 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+0xbe1/0x1020
 queue_work_on+0x106/0x1d0
 __udp_tunnel_nic_add_port+0xb71/0xd60
 udp_tunnel_push_rx_port+0x186/0x210
 geneve_offload_rx_ports+0xc7/0x150
 geneve_netdevice_event+0x6a/0x80
 notifier_call_chain+0x1be/0x400
 call_netdevice_notifiers+0x90/0xd0
 udp_tunnel_nic_netdevice_event+0xdef/0x17d0
 notifier_call_chain+0x1be/0x400
 register_netdevice+0x173a/0x1cf0
 nsim_create+0xb92/0x1100
 __nsim_dev_port_add+0x72a/0xb50
 nsim_dev_port_add_all+0x37/0xf0
 nsim_dev_reload_up+0x45f/0x7c0
 devlink_reload+0x505/0x8d0
 devlink_nl_reload_doit+0xaaa/0xc80
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x80f/0x9b0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0xa68/0xad0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x14d/0xf80
 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+0xd03/0x1020
 queue_work_on+0x106/0x1d0
 __udp_tunnel_nic_add_port+0xb71/0xd60
 udp_tunnel_push_rx_port+0x186/0x210
 vxlan_offload_rx_ports+0x129/0x1f0
 vxlan_netdevice_event+0x111/0x480
 notifier_call_chain+0x1be/0x400
 call_netdevice_notifiers+0x90/0xd0
 udp_tunnel_nic_netdevice_event+0xdef/0x17d0
 notifier_call_chain+0x1be/0x400
 register_netdevice+0x173a/0x1cf0
 nsim_create+0xb92/0x1100
 __nsim_dev_port_add+0x72a/0xb50
 nsim_dev_port_add_all+0x37/0xf0
 nsim_dev_reload_up+0x45f/0x7c0
 devlink_reload+0x505/0x8d0
 devlink_nl_reload_doit+0xaaa/0xc80
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x80f/0x9b0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0xa68/0xad0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816aec2a00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 176 bytes inside of
 freed 256-byte region [ffff88816aec2a00, ffff88816aec2b00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16aec2
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 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff888100041b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 057ff00000000001 ffffea0005abb081 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 9653, tgid 9643 (syz.2.1032), ts 138325250885, free_ts 115521845804
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x24dc/0x2580
 __alloc_frozen_pages_noprof+0x18d/0x380
 allocate_slab+0x77/0x660
 refill_objects+0x331/0x3c0
 __pcs_replace_empty_main+0x2b9/0x620
 __kmalloc_noprof+0x474/0x760
 __register_sysctl_table+0xba1/0x1340
 __addrconf_sysctl_register+0x331/0x4d0
 addrconf_sysctl_register+0x168/0x1c0
 ipv6_add_dev+0xd26/0x13a0
 addrconf_notify+0x771/0x1050
 notifier_call_chain+0x1be/0x400
 register_netdevice+0x173a/0x1cf0
 register_netdev+0x40/0x60
 vti6_init_net+0x238/0x370
page last free pid 5873 tgid 5873 stack trace:
 __free_frozen_pages+0xc2b/0xdb0
 vfree+0x25a/0x400
 delayed_vfree_work+0x55/0x80
 process_scheduled_works+0xb02/0x1830
 worker_thread+0xa50/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

Memory state around the buggy address:
 ffff88816aec2980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816aec2a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88816aec2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88816aec2b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816aec2b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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