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ida_free called for id=1544 which is not allocated.
WARNING: CPU: 0 PID: 6532 at lib/idr.c:592 ida_free+0x280/0x310
Modules linked in:
CPU: 0 UID: 0 PID: 6532 Comm: syz.0.132 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
RIP: 0010:ida_free+0x280/0x310
Code: 00 00 00 00 fc ff df 48 8b 5c 24 10 48 8b 7c 24 40 48 89 de e8 d1 8a 0c 00 90 48 c7 c7 80 ee ba 8c 44 89 fe e8 11 87 12 f6 90 <0f> 0b 90 90 eb 34 e8 95 02 4f f6 49 bd 00 00 00 00 00 fc ff df eb
RSP: 0018:ffffc90006aa76a0 EFLAGS: 00010246
RAX: a7f6ac6f96879100 RBX: 0000000000000a06 RCX: ffff8880230f9cc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc90006aa7798 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa1f4 R12: 1ffff92000d54ed8
R13: dffffc0000000000 R14: ffff88810be9ce00 R15: 0000000000000608
FS:  0000555574980500(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c37aba3 CR3: 0000000027be4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 pde_put+0x7e/0x1b0
 remove_proc_subtree+0x3e8/0x530
 snmp6_unregister_dev+0xae/0xf0
 addrconf_ifdown+0x240/0x1880
 addrconf_notify+0x1bc/0x1010
 notifier_call_chain+0x1b6/0x3e0
 unregister_netdevice_many_notify+0x14d7/0x1ff0
 unregister_netdevice_queue+0x33c/0x380
 __tun_detach+0xda4/0x1560
 tun_chr_close+0x10a/0x1c0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c7578eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffb14f5db8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000000dfda RCX: 00007f0c7578eba9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f0c759d7da0 R08: 0000000000000001 R09: 0000001ab14f60af
R10: 0000001b30f20000 R11: 0000000000000246 R12: 00007f0c759d5fac
R13: 00007f0c759d5fa0 R14: ffffffffffffffff R15: 00007fffb14f5ed0
 </TASK>
